Posts on CX 的博客

Hugo 使用指南

Sat, 17 Oct 2026 00:00:00 +0000

Hugo v0.168.0 的安装、写作、主题、多语言、Git 子模块、构建与 Gitea Actions 实践。

中国秸秆禁烧政策的历史：从传统农耕到现代环境治理

Sat, 17 Oct 2026 17:47:18 +0800

中国秸秆禁烧政策的历史，实际上是中国农业现代化、农村能源转型、环境治理和基层行政管理方式演变的一个缩影。

最关键的历史结论是：中国并非自古存在大规模秸秆焚烧问题，也不是近年来才开始禁止烧秸秆。现代秸秆禁烧制度在20世纪90年代逐步建立，1999年形成全国性的管理规定，2008年前后明显强化，2013年以后进一步纳入大气污染防治体系。

更值得研究的，是政策治理目标与执行方式之间的变化：

最初的重点是公共安全。尤其是机场、铁路、公路附近的焚烧风险，同时兼顾大气污染。
后来逐渐转向区域空气质量管理。秸秆焚烧与城市雾霾、PM2.5治理建立了更紧密的政策联系。
再后来出现基层执行范围扩大和管理方式强化的问题。一些地方采取全面禁烧、网格巡查和责任追究，导致政策成本与农民生产需求之间的矛盾。
政策争论的核心不是焚烧是否产生污染，而是应当禁止到什么程度，以及由谁承担处理秸秆的经济成本。

一、历史时间线：秸秆禁烧如何一步步形成

20世纪80年代以前

秸秆是有使用价值的农业资源

主要用于烧饭取暖、牲畜饲料、垫圈积肥、堆肥和建材。露天焚烧存在，但大量秸秆并非没有用途。

1980年代末—1990年代

大规模集中焚烧成为社会问题

农业机械化、农村生活燃料转型、粮食增产及农业劳动力转移，使部分地区秸秆集中剩余，焚烧逐渐成为快速清田的方式。

1999—2000年

全国性禁烧管理制度确立

1999年六部门发布《秸秆禁烧和综合利用管理办法》；2000年修订《大气污染防治法》，明确特定区域的秸秆露天焚烧禁令。

2008年

奥运空气质量保障推动强化禁烧

京津冀及周边多个省份实施重点时段严格禁烧，城市及重点区域管控范围扩大。

2013—2017年

与PM2.5及大气污染防治绑定

大气污染防治行动全面推进。2015年修订《大气污染防治法》，规定由省级人民政府划定禁烧区域，并明确相关法律责任。

2018年至今

基层精细化监管与政策争议并存

网格监管、卫星火点监测及秸秆综合利用持续推进，部分地区也探索分区、分时段的焚烧管理。

上面的阶段划分依据国家层面的重要政策节点，而非认为每一年全国都同步改变。

二、1949—1980年代：为什么过去农民很少需要大规模集中烧秸秆？

要解释今天的禁烧政策，必须先理解一个历史变化：

秸秆从过去的生产生活资源，逐渐变成了部分地区需要付费处理的农业副产物。

1. 传统农村社会有较完整的秸秆利用体系

过去的小农经济中，秸秆具有多种实际用途。

用途	农村的典型做法
生活燃料	使用麦秸、稻草、玉米秆烧饭取暖
牲畜饲料	秸秆切碎后喂牛、羊等反刍动物
农业肥料	堆肥、沤肥、垫圈积肥、直接还田
生活材料	编织草席、制作草绳、屋顶覆盖
农业辅助	覆盖地面、保墒、防止部分土壤侵蚀

这并不意味着过去不存在焚烧。农民同样会焚烧残茬、杂草，或通过草木灰补充部分矿质养分。

一把火，三十年：中国秸秆禁烧为何从重点管控走向全域禁烧？（二）

Sat, 17 Oct 2026 12:00:00 +0800

深度回顾2008—2015年中国秸秆禁烧政策的关键转折：奥运空气质量保障、江苏全域禁烧、安徽财政奖补考核、湖北立法与卫星火点监测。

My First Post

Sat, 22 Mar 2025 20:00:42 +0800

Azure入门指南（一）

Sun, 18 Jun 2023 12:25:00 +0000

阅读前提：了解国内外云服务（如阿里云、Amazon Web Services），并有一定的使用经验

注册

注册一个微软账户即可，具体步骤可以参考知乎的这篇文章（如何白嫖微软Azure12个月及避坑指南 - 知乎 (zhihu.com)），

注意：这篇文章写了有很久了，azure的策略可能已经更改，由此可能产生费用，大家实践的时候一定要看清收费策略，或者提前咨询客服，避免不必要的损失。

Azure服务

以下是常用的azure服务：

以下表格是Azure、阿里云和AWS的云服务的对应关系

Azure	阿里云	AWS
订阅（Subscriptions）
资源组（Resource groups）	资源组
虚拟机（Virtual machine）	云服务器ECS	EC2
磁盘（Disk）	云盘	卷（Volume）
虚拟网络（Virtual network）	专有网络	VPC
网络接口（Network Interface）	交换机	网络接口（Network interface）
网络安全组（Network security group）	安全组	安全组（Security Group）
公共 IP 地址（Public IP address）	公网IP	公有 IPv4 /IPv6地址（Public IPv4/IPv6 address）
SSH 密钥（SSH key）	密钥对	密钥对（Key Pair）

虚拟机

创建

基本

Debian-Ubuntu使用Nexus的私有镜像源

Thu, 27 Oct 2022 15:24:18 +0000

# Debian/Ubuntu使用Nexus的私有镜像源

以Debian11为例

修改**/etc/apt/source.list**

vim /etc/apt/source.list

# deb cdrom:[Debian GNU/Linux 11.2.0 _Bullseye_ - Official amd64 DVD Binary-1 20211218-11:13]/ bullseye contrib main

#deb cdrom:[Debian GNU/Linux 11.2.0 _Bullseye_ - Official amd64 DVD Binary-1 20211218-11:13]/ bullseye contrib main

deb http://deb.debian.org/debian/ bullseye main
deb-src http://deb.debian.org/debian/ bullseye main

deb http://security.debian.org/debian-security bullseye-security main contrib
deb-src http://security.debian.org/debian-security bullseye-security main contrib

# bullseye-updates, to get updates before a point release is made;
# see https://www.debian.org/doc/manuals/debian-reference/ch02.en.html#_updates_and_backports
deb http://deb.debian.org/debian/ bullseye-updates main contrib
deb-src http://deb.debian.org/debian/ bullseye-updates main contrib

把其中的地址替换成你的私有镜像源地址

# deb cdrom:[Debian GNU/Linux 11.2.0 _Bullseye_ - Official amd64 DVD Binary-1 20211218-11:13]/ bullseye contrib main

#deb cdrom:[Debian GNU/Linux 11.2.0 _Bullseye_ - Official amd64 DVD Binary-1 20211218-11:13]/ bullseye contrib main

deb http://mirror.nfools.org:8081/repository/debian-bullseye/ bullseye main
deb-src http://mirror.nfools.org:8081/repository/debian-bullseye/ bullseye main

deb http://security.debian.org/debian-security bullseye-security main contrib
deb-src http://security.debian.org/debian-security bullseye-security main contrib

# bullseye-updates, to get updates before a point release is made;
# see https://www.debian.org/doc/manuals/debian-reference/ch02.en.html#_updates_and_backports
deb http://deb.debian.org/debian/ bullseye-updates main contrib
deb-src http://deb.debian.org/debian/ bullseye-updates main contrib

保存并退出

创建**/etc/apt/auth.conf.d/nexus.local.intranet.conf**（如果你的仓库允许匿名访问，则忽略这一步）
```
vim /etc/apt/auth.conf.d/nexus.local.intranet.conf
```
配置你的镜像源地址、登录名和密码
```
machine http://mirror.nfools.org:8081/
login public
password public
```
保存并退出
更新apt
```
apt update
```

mybatis xml的字符串表达式中不要包含in（因为in是关键字，除此之外，还有很多关键字都不要放在这里）！！！

Tue, 11 Oct 2022 15:09:00 +0000

假如你要使用**if**语句判断**Query**类的成员变量**in**是否为**null**，你可能会这么写： ``````（错误）

正确的做法是把Query类的in变量名改成其它名字，比如改成contains <if test="null != query.contains"></if>（正确）

群晖Gitlab开启https

Fri, 07 Oct 2022 14:06:00 +0000

1.在套件中心停用Gitlab。

2.打开docker，右键编辑synology_gitlab，在端口设置中将本地端口44333（自定义），映射到容器端口443，然后在环境变量中新增GITLAB_HTTPS true 完成以上步骤后，重启Gitlab，就可以在浏览器上使用https访问Gitlab了。但是当使用克隆代码时，仍然是使用原来的端口。 3.在环境变量中修改GITLAB_PORT的值为44333（自定义）然后重启Gitlab就完事了。

MySQL8.0主从同步

Fri, 09 Sep 2022 09:51:29 +0000

# MySQL8.0主从同步

参考：https://www.cnblogs.com/kylinlin/p/5258719.html

一、主数据库

1.修改配置文件

vim /etc/mysql/mysql.conf.d/mysqld.cnf

[mysqld]

log-bin=mysql-bin

server-id=1

2.锁表

mysql > flush tables with read lock;

3.备份

mysqldump -u root -p 'root' -S /var/run/mysqld/mysqld.sock kpc | gzip > /tmp/mysql_bak.$(date +%F).sql.gz

4.创建用户并授权

CREATE USER 'rep'@'%' IDENTIFIED WITH mysql_native_password BY 'rep';

GRANT REPLICATION SLAVE ON *.* TO 'rep'@'%';

5.记录信息

mysql > show master status;

6.重启

sudo systemctl restart mysql

二、从数据库

1.修改配置文件

vim /etc/mysql/mysql.conf.d/mysqld.cnf

[server-id != 1](# 1.修改配置文件)

[mysqld]

server-id=2

2.配置Master

[MASTER_USER](# 4.创建用户)

[MASTER_PASSWORD](# 4.创建用户)

[MASTER_LOG_FILE](# 5.记录信息)

[MASTER_LOG_POS](# 5.记录信息)

mysql> CHANGE MASTER TO

-> MASTER_HOST='master_host_name',

-> MASTER_USER='rep',

-> MASTER_PASSWORD='rep',

-> MASTER_LOG_FILE='mysql-bin.000001',

-> MASTER_LOG_POS=156

3.运行

mysql > start slave;

Spring Cloud Alibaba 2021.0.1.0 踩坑记录

Sun, 04 Sep 2022 15:27:00 +0000

我打算把**Spring Cloud Alibaba**升级个版本，看看有什么新特性，结果升级后死活启动不了。

事情是这样的，跟往常一样，我先去Spring官网找到Spring Cloud Alibaba的最新的版本号，如下图所示：

可以看到最新的版本是2021.0.1.0

我默默记下这个版本号… 然后点了右上角的那只章鱼猫 在Wiki里找到版本说明，如下图所示：现在我知道了Spring Cloud Alibaba Version、Spring Cloud Version和Spring Boot Version三者版本对应关系了！

我再次回到Spring官网，然后打开Spring Cloud Alibaba的Reference，根据文档，一顿操作。其实大概就只有三步：

添加依赖

<!--在父工程添加以下依赖-->
<properties>
 <spring.cloud.version>2021.0.1</spring.cloud.version>
 <spring-boot-dependencies.version>2.6.3</spring-boot-dependencies.version>
 <com.alibaba.cloud.spring-cloud-alibaba-dependencies.version>2021.0.1.0
 </com.alibaba.cloud.spring-cloud-alibaba-dependencies.version>
</properties>
<dependencyManagement>
 <dependencies>
 <!--官网里使用spring-boot-starter-parent作为父工程而没有导入这条依赖，实际作用相同-->
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-dependencies</artifactId>
 <version>${spring-boot-dependencies.version}</version>
 </dependency>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-dependencies</artifactId>
 <version>${spring.cloud.version}</version>
 <type>pom</type>
 <scope>import</scope>
 </dependency>
 <dependency>
 <groupId>com.alibaba.cloud</groupId>
 <artifactId>spring-cloud-alibaba-dependencies</artifactId>
 <version>${com.alibaba.cloud.spring-cloud-alibaba-dependencies.version}</version>
 <type>pom</type>
 <scope>import</scope>
 </dependency>
 </dependencies>
</dependencyManagement>

<!--在module中添加以下依赖-->
<dependency>
 <groupId>com.alibaba.cloud</groupId>
 <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

配置yaml

spring:
 cloud:
 nacos:
 discovery:
 server-addr: 127.0.0.1:8848

在主类上添加**@EnableDiscoveryClient**注解激动的心，颤抖的手，点击运行！（提前启动好了Nacos）

2022-09-05 00:04:32.047 INFO 37828 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2022-09-05 00:04:32.047 INFO 37828 --- [ restartedMain] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.56]
2022-09-05 00:04:32.109 INFO 37828 --- [ restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2022-09-05 00:04:32.109 INFO 37828 --- [ restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1320 ms
2022-09-05 00:04:32.504 WARN 37828 --- [ restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerAdapter' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageConverters' defined in class path resource [org/springframework/boot/autoconfigure/http/HttpMessageConvertersAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.autoconfigure.http.HttpMessageConverters]: Factory method 'messageConverters' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
2022-09-05 00:04:32.507 INFO 37828 --- [ restartedMain] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2022-09-05 00:04:32.523 INFO 37828 --- [ restartedMain] ConditionEvaluationReportLoggingListener :

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-09-05 00:04:32.551 ERROR 37828 --- [ restartedMain] o.s.boot.SpringApplication : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerAdapter' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageConverters' defined in class path resource [org/springframework/boot/autoconfigure/http/HttpMessageConvertersAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.autoconfigure.http.HttpMessageConverters]: Factory method 'messageConverters' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.15.jar:5.3.15]
 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.15.jar:5.3.15]
 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.3.jar:2.6.3]
 at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) ~[spring-boot-2.6.3.jar:2.6.3]
 at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:414) ~[spring-boot-2.6.3.jar:2.6.3]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:302) ~[spring-boot-2.6.3.jar:2.6.3]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1303) ~[spring-boot-2.6.3.jar:2.6.3]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1292) ~[spring-boot-2.6.3.jar:2.6.3]
 at cn.imcaoxuan.FileManagerApplication.main(FileManagerApplication.java:11) ~[classes/:na]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
 at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
 at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
 at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.6.3.jar:2.6.3]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageConverters' defined in class path resource [org/springframework/boot/autoconfigure/http/HttpMessageConvertersAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.autoconfigure.http.HttpMessageConverters]: Factory method 'messageConverters' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 24 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageConverters' defined in class path resource [org/springframework/boot/autoconfigure/http/HttpMessageConvertersAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.autoconfigure.http.HttpMessageConverters]: Factory method 'messageConverters' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1389) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.getIfAvailable(DefaultListableBeanFactory.java:2030) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.ifAvailable(DefaultListableBeanFactory.java:2041) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.configureMessageConverters(WebMvcAutoConfiguration.java:232) ~[spring-boot-autoconfigure-2.6.3.jar:2.6.3]
 at org.springframework.web.servlet.config.annotation.WebMvcConfigurerComposite.configureMessageConverters(WebMvcConfigurerComposite.java:137) ~[spring-webmvc-5.3.15.jar:5.3.15]
 at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration.configureMessageConverters(DelegatingWebMvcConfiguration.java:118) ~[spring-webmvc-5.3.15.jar:5.3.15]
 at org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.getMessageConverters(WebMvcConfigurationSupport.java:865) ~[spring-webmvc-5.3.15.jar:5.3.15]
 at org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.requestMappingHandlerAdapter(WebMvcConfigurationSupport.java:673) ~[spring-webmvc-5.3.15.jar:5.3.15]
 at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration.requestMappingHandlerAdapter(WebMvcAutoConfiguration.java:419) ~[spring-boot-autoconfigure-2.6.3.jar:2.6.3]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
 at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
 at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 25 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.autoconfigure.http.HttpMessageConverters]: Factory method 'messageConverters' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 49 common frames omitted
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mappingJackson2HttpMessageConverter' defined in class path resource [org/springframework/boot/autoconfigure/http/JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration.class]: Unsatisfied dependency expressed through method 'mappingJackson2HttpMessageConverter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:541) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1614) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1571) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveMultipleBeans(DefaultListableBeanFactory.java:1415) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1347) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.resolveStream(DefaultListableBeanFactory.java:2117) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.orderedStream(DefaultListableBeanFactory.java:2111) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration.messageConverters(HttpMessageConvertersAutoConfiguration.java:70) ~[spring-boot-autoconfigure-2.6.3.jar:2.6.3]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
 at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
 at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
 at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 50 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jacksonObjectMapper' defined in class path resource [org/springframework/boot/autoconfigure/jackson/JacksonAutoConfiguration$JacksonObjectMapperConfiguration.class]: Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:597) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1389) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1309) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:887) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 72 common frames omitted
Caused by: java.lang.IllegalStateException: Failed to introspect Class [com.fasterxml.jackson.databind.ObjectMapper] from ClassLoader [jdk.internal.loader.ClassLoaders$AppClassLoader@2437c6dc]
 at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:481) ~[spring-core-5.3.15.jar:5.3.15]
 at org.springframework.util.ReflectionUtils.doWithLocalMethods(ReflectionUtils.java:321) ~[spring-core-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.buildLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:232) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.findLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:210) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(InitDestroyAnnotationBeanPostProcessor.java:149) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(CommonAnnotationBeanPostProcessor.java:305) ~[spring-context-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:1116) ~[spring-beans-5.3.15.jar:5.3.15]
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.3.15.jar:5.3.15]
 ... 82 common frames omitted
Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/exc/StreamWriteException
 at java.base/java.lang.Class.getDeclaredMethods0(Native Method) ~[na:na]
 at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3167) ~[na:na]
 at java.base/java.lang.Class.getDeclaredMethods(Class.java:2310) ~[na:na]
 at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:463) ~[spring-core-5.3.15.jar:5.3.15]
 ... 89 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.core.exc.StreamWriteException
 at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582) ~[na:na]
 at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
 at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
 ... 93 common frames omitted

Disconnected from the target VM, address: '127.0.0.1:59002', transport: 'socket'

Process finished with exit code 0

报错提示ClassNotFoundException，很明显，这种问题一般都是出现在缺少依赖的情况下的，但是jackson这个东西，我之前一直用的好好的啊！怎么突然就说找不到了呢？我在密密麻麻的POM文件中看了半天，也没发现什么问题。我也没做多大改动啊，怎么就跑不起来了呢？我想了下，问题会不会是依赖冲突导致的？我去看看External Libraries：

Gradle 添加私有仓库

Thu, 25 Aug 2022 09:18:33 +0000

# Gradle 添加私有仓库

以Android Studio为例

在build.gradle(Project)中添加maven{…}，如下所示：

buildscript {
 repositories {
 maven {
 url "https://maven.imcaoxuan.cn:8443/repository/public/"
 credentials {
 username = 'public'
 password = 'public'
 }
 }
 google()
 mavenCentral()
 }
 dependencies {
 classpath 'com.android.tools.build:gradle:7.0.4'

 // NOTE: Do not place your application dependencies here; they belong
 // in the individual module build.gradle files
 }
}

在settings.gradle(Project)中添加maven{…}，如下所示：

dependencyResolutionManagement {
 repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
 repositories {
 maven {
 url "https://maven.imcaoxuan.cn:8443/repository/public/"
 credentials {
 username = 'public'
 password = 'public'
 }
 }
 google()
 mavenCentral()
 jcenter() // Warning: this repository is going to shut down soon
 }
}

3.Sync now!

转发：解决warning: LF will be replaced by CRLF in方法

Sun, 21 Aug 2022 07:03:21 +0000

[https://blog.csdn.net/chenxijie1985/article/details/107759826][1]

在windows下add代码时一直提示：warning: LF will be replaced by CRLF in，虽然没多大影响，但是看得不爽。

解决办法：

git config –global core.autocrlf false

转发：Ubuntu 创建 RAID1 阵列

Sun, 24 Jul 2022 15:55:00 +0000

转发：https://www.jianshu.com/p/3e6d5da2db81

# 列出所有磁盘信息
$ sudo fdisk -l

# 建立分区
$ sudo fdisk /dev/sdb

# 然后依次输入
$ n (新建分区表)
$ p (主分区，然后根据提示操作)
$ w (保存分区信息)

$ sudo mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1
mdadm: Note: this array has metadata at the start and
 may not be suitable as a boot device. If you plan to
 store '/boot' on this device please ensure that
 your boot-loader understands md/v1.x metadata, or use
 --metadata=0.90
mdadm: size set to 20953088K
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

JAVA_HOME

Sun, 17 Jul 2022 13:36:33 +0000

# JAVA_HOME

#JAVA_HOME
export JAVA_HOME=/opt/jdk1.8.0_201
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

定时任务

Sun, 17 Jul 2022 13:34:49 +0000

# 定时任务

example:

*/1 * * * * /home/admin/traffic.sh echo > /home/admin/log/traffic.log

Ubuntu修改代理

Sun, 17 Jul 2022 13:33:27 +0000

# Ubuntu修改代理

vim /etc/apt/apt.conf.d/90curtin-aptproxy

然后…

整合代码：TOTP+Hex+Base32

Tue, 22 Mar 2022 11:54:00 +0000

代码引用：org.apache.commons.codec.binary.Base32, org.apache.commons.codec.binary.Hex, TOTP(Johan Rydell, PortWise, Inc)

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.lang.reflect.UndeclaredThrowableException;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.GeneralSecurityException;
import java.util.Arrays;


public class TotpDemo {
 private static final int[] DIGITS_POWER
 // 0 1 2 3 4 5 6 7 8
 = {1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000};

 public static void main(String[] args) {
 // todo
 String secretKey = "";
 Base32 base32 = new Base32();
 byte[] bytes = base32.decode(secretKey.toUpperCase());
 // [-84, -88, -126, -19, 116, -72, -61, -58, 117, 53]
 String hexKey = Hex.encodeHexString(bytes);
 String hexTime = Long.toHexString(System.currentTimeMillis() / 30 / 1000);
 System.out.println(generateTOTP(hexKey, hexTime, "6"));
 }

 static class Hex {
 public static String encodeHexString(final byte[] data) {
 return new String(encodeHex(data));
 }

 public static char[] encodeHex(final byte[] data) {
 return encodeHex(data, true);
 }

 public static char[] encodeHex(final byte[] data, final boolean toLowerCase) {
 return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);
 }

 protected static char[] encodeHex(final byte[] data, final char[] toDigits) {
 final int l = data.length;
 final char[] out = new char[l << 1];
 // two characters form the hex value.
 for (int i = 0, j = 0; i < l; i++) {
 out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
 out[j++] = toDigits[0x0F & data[i]];
 }
 return out;
 }

 private static final char[] DIGITS_LOWER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
 'e', 'f'};

 /**
 * Used to build output as Hex
 */
 private static final char[] DIGITS_UPPER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
 'E', 'F'};
 }

 public static String generateTOTP(String key,
 String time,
 String returnDigits) {
 return generateTOTP(key, time, returnDigits, "HmacSHA1");
 }

 private static byte[] hmac_sha1(String crypto, byte[] keyBytes,
 byte[] text) {
 try {
 Mac hmac;
 hmac = Mac.getInstance(crypto);
 SecretKeySpec macKey =
 new SecretKeySpec(keyBytes, "RAW");
 hmac.init(macKey);
 return hmac.doFinal(text);
 } catch (GeneralSecurityException gse) {
 throw new UndeclaredThrowableException(gse);
 }
 }

 private static byte[] hexStr2Bytes(String hex) {
 // Adding one byte to get the right conversion
 // values starting with "0" can be converted
 byte[] bArray = new BigInteger("10" + hex, 16).toByteArray();

 // Copy all the REAL bytes, not the "first"
 byte[] ret = new byte[bArray.length - 1];
 for (int i = 0; i < ret.length; i++)
 ret[i] = bArray[i + 1];
 return ret;
 }

 private static String generateTOTP(String key,
 String time,
 String returnDigits,
 String crypto) {
 int codeDigits = Integer.decode(returnDigits).intValue();
 String result;
 byte[] hash;

 // Using the counter
 // First 8 bytes are for the movingFactor
 // Complaint with base RFC 4226 (HOTP)
 while (time.length() < 16)
 time = "0" + time;

 // Get the HEX in a Byte[]
 byte[] msg = hexStr2Bytes(time);

 // Adding one byte to get the right conversion
 byte[] k = hexStr2Bytes(key);

 hash = hmac_sha1(crypto, k, msg);

 // put selected bytes into result int
 int offset = hash[hash.length - 1] & 0xf;

 int binary =
 ((hash[offset] & 0x7f) << 24) |
 ((hash[offset + 1] & 0xff) << 16) |
 ((hash[offset + 2] & 0xff) << 8) |
 (hash[offset + 3] & 0xff);

 int otp = binary % DIGITS_POWER[codeDigits];

 result = Integer.toString(otp);
 while (result.length() < codeDigits) {
 result = "0" + result;
 }
 return result;
 }

 static abstract class BaseNCodec {
 static final int EOF = -1;
 protected final byte pad;
 protected static final int MASK_8BITS = 0xff;
 protected static final byte PAD_DEFAULT = '='; // Allow static access to default
 private final int unencodedBlockSize;

 /**
 * Number of bytes in each full block of encoded data, e.g. 3 for Base64 and 8 for Base32
 */
 private final int encodedBlockSize;
 protected final int lineLength;

 /**
 * Size of chunk separator. Not used unless {@link #lineLength} &gt; 0.
 */
 private final int chunkSeparatorLength;

 protected BaseNCodec(final int unencodedBlockSize, final int encodedBlockSize,
 final int lineLength, final int chunkSeparatorLength, final byte pad) {
 this.unencodedBlockSize = unencodedBlockSize;
 this.encodedBlockSize = encodedBlockSize;
 final boolean useChunking = lineLength > 0 && chunkSeparatorLength > 0;
 this.lineLength = useChunking ? (lineLength / encodedBlockSize) * encodedBlockSize : 0;
 this.chunkSeparatorLength = chunkSeparatorLength;

 this.pad = pad;
 }

 public byte[] decode(final String pArray) {
 return decode(pArray.getBytes(StandardCharsets.UTF_8));
 }

 public byte[] decode(final byte[] pArray) {
 if (pArray == null || pArray.length == 0) {
 return pArray;
 }
 final Context context = new Context();
 decode(pArray, 0, pArray.length, context);
 decode(pArray, 0, EOF, context); // Notify decoder of EOF.
 final byte[] result = new byte[context.pos];
 readResults(result, 0, result.length, context);
 return result;
 }

 abstract void decode(byte[] pArray, int i, int length, Context context);

 int readResults(final byte[] b, final int bPos, final int bAvail, final Context context) {
 if (context.buffer != null) {
 final int len = Math.min(available(context), bAvail);
 System.arraycopy(context.buffer, context.readPos, b, bPos, len);
 context.readPos += len;
 if (context.readPos >= context.pos) {
 context.buffer = null; // so hasData() will return false, and this method can return -1
 }
 return len;
 }
 return context.eof ? EOF : 0;
 }

 int available(final Context context) { // package protected for access from I/O streams
 return context.buffer != null ? context.pos - context.readPos : 0;
 }

 protected byte[] ensureBufferSize(int size, Context context) {
 if (context.buffer == null) {
 context.buffer = new byte[this.getDefaultBufferSize()];
 context.pos = 0;
 context.readPos = 0;
 } else if (context.pos + size - context.buffer.length > 0) {
 return resizeBuffer(context, context.pos + size);
 }

 return context.buffer;
 }

 protected int getDefaultBufferSize() {
 return 8192;
 }

 private static byte[] resizeBuffer(Context context, int minCapacity) {
 int oldCapacity = context.buffer.length;
 int newCapacity = oldCapacity * 2;
 if (compareUnsigned(newCapacity, minCapacity) < 0) {
 newCapacity = minCapacity;
 }

 if (compareUnsigned(newCapacity, 2147483639) > 0) {
 newCapacity = createPositiveCapacity(minCapacity);
 }

 byte[] b = new byte[newCapacity];
 System.arraycopy(context.buffer, 0, b, 0, context.buffer.length);
 context.buffer = b;
 return b;
 }

 private static int compareUnsigned(int x, int y) {
 return Integer.compare(x + -2147483648, y + -2147483648);
 }

 private static int createPositiveCapacity(int minCapacity) {
 if (minCapacity < 0) {
 throw new OutOfMemoryError("Unable to allocate array size: " + ((long) minCapacity & 4294967295L));
 } else {
 return minCapacity > 2147483639 ? minCapacity : 2147483639;
 }
 }

 protected boolean containsAlphabetOrPad(final byte[] arrayOctet) {
 if (arrayOctet == null) {
 return false;
 }
 for (final byte element : arrayOctet) {
 if (pad == element || isInAlphabet(element)) {
 return true;
 }
 }
 return false;
 }

 protected abstract boolean isInAlphabet(byte value);

 protected static boolean isWhiteSpace(final byte byteToCheck) {
 switch (byteToCheck) {
 case ' ':
 case '\n':
 case '\r':
 case '\t':
 return true;
 default:
 return false;
 }
 }

 static class Context {
 int ibitWorkArea;
 long lbitWorkArea;
 byte[] buffer;
 int pos;
 int readPos;
 boolean eof;
 int currentLinePos;
 int modulus;

 Context() {
 }

 public String toString() {
 return String.format("%s[buffer=%s, currentLinePos=%s, eof=%s, ibitWorkArea=%s, lbitWorkArea=%s, modulus=%s, pos=%s, readPos=%s]", this.getClass().getSimpleName(), Arrays.toString(this.buffer), this.currentLinePos, this.eof, this.ibitWorkArea, this.lbitWorkArea, this.modulus, this.pos, this.readPos);
 }
 }
 }

 static class Base32 extends TotpForXuandembp.BaseNCodec {
 private final int decodeSize;
 private final int encodeSize;
 private final byte[] decodeTable;
 private final byte[] encodeTable;
 private final byte[] lineSeparator;

 private static final int BITS_PER_ENCODED_BYTE = 5;
 private static final int BYTES_PER_ENCODED_BLOCK = 8;
 private static final int BYTES_PER_UNENCODED_BLOCK = 5;
 private static final long MASK_2BITS = 0x03L;
 private static final long MASK_7BITS = 0x7fL;
 /**
 * Mask used to extract 6 bits, used when decoding final trailing character.
 */
 private static final long MASK_6BITS = 0x3fL;
 /**
 * Mask used to extract 5 bits, used when encoding Base32 bytes
 */
 private static final int MASK_5BITS = 0x1f;
 /**
 * Mask used to extract 4 bits, used when decoding final trailing character.
 */
 private static final long MASK_4BITS = 0x0fL;
 /**
 * Mask used to extract 3 bits, used when decoding final trailing character.
 */
 private static final long MASK_3BITS = 0x07L;
 /** Mask used to extract 2 bits, used when decoding final trailing character. */
 /**
 * Mask used to extract 1 bits, used when decoding final trailing character.
 */
 private static final long MASK_1BITS = 0x01L;

 public Base32() {
 this(false);
 }

 public Base32(final boolean useHex) {
 this(0, null, useHex, PAD_DEFAULT);
 }

 public Base32(final int lineLength, final byte[] lineSeparator, final boolean useHex, final byte pad) {
 super(BYTES_PER_UNENCODED_BLOCK, BYTES_PER_ENCODED_BLOCK, lineLength,
 lineSeparator == null ? 0 : lineSeparator.length, pad);
 if (useHex) {
 this.encodeTable = HEX_ENCODE_TABLE;
 this.decodeTable = HEX_DECODE_TABLE;
 } else {
 this.encodeTable = ENCODE_TABLE;
 this.decodeTable = DECODE_TABLE;
 }
 if (lineLength > 0) {
 if (lineSeparator == null) {
 throw new IllegalArgumentException("lineLength " + lineLength + " > 0, but lineSeparator is null");
 }
 // Must be done after initializing the tables
 if (containsAlphabetOrPad(lineSeparator)) {
 final String sep = new String(lineSeparator, StandardCharsets.UTF_8);
 throw new IllegalArgumentException("lineSeparator must not contain Base32 characters: [" + sep + "]");
 }
 this.encodeSize = BYTES_PER_ENCODED_BLOCK + lineSeparator.length;
 this.lineSeparator = new byte[lineSeparator.length];
 System.arraycopy(lineSeparator, 0, this.lineSeparator, 0, lineSeparator.length);
 } else {
 this.encodeSize = BYTES_PER_ENCODED_BLOCK;
 this.lineSeparator = null;
 }
 this.decodeSize = this.encodeSize - 1;

 if (isInAlphabet(pad) || isWhiteSpace(pad)) {
 throw new IllegalArgumentException("pad must not be in alphabet or whitespace");
 }
 }

 private static final byte[] HEX_DECODE_TABLE = {
 // 0 1 2 3 4 5 6 7 8 9 A B C D E F
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f
 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, // 30-3f 2-7
 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 40-4f A-O
 25, 26, 27, 28, 29, 30, 31, // 50-56 P-V
 -1, -1, -1, -1, -1, -1, -1, -1, -1, // 57-5f Z-_
 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 60-6f `-o
 25, 26, 27, 28, 29, 30, 31 // 70-76 p-v
 };

 /**
 * This array is a lookup table that translates 5-bit positive integer index values into their
 * "Base32 Hex Alphabet" equivalents as specified in Table 4 of RFC 4648.
 */
 private static final byte[] HEX_ENCODE_TABLE = {
 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
 };
 private static final byte[] DECODE_TABLE = {
 // 0 1 2 3 4 5 6 7 8 9 A B C D E F
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 00-0f
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 10-1f
 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 20-2f
 -1, -1, 26, 27, 28, 29, 30, 31, -1, -1, -1, -1, -1, -1, -1, -1, // 30-3f 2-7
 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 40-4f A-O
 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 50-5a P-Z
 -1, -1, -1, -1, -1, // 5b - 5f
 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 60 - 6f a-o
 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 70 - 7a p-z/**/
 };

 /**
 * This array is a lookup table that translates 5-bit positive integer index values into their "Base32 Alphabet"
 * equivalents as specified in Table 3 of RFC 4648.
 */
 private static final byte[] ENCODE_TABLE = {
 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
 '2', '3', '4', '5', '6', '7',
 };

 private static void validateCharacter(final long emptyBitsMask, final Context context) {
 // Use the long bit work area
 if ((context.lbitWorkArea & emptyBitsMask) != 0) {
 throw new IllegalArgumentException(
 "Last encoded character (before the paddings if any) is a valid base 32 alphabet but not a possible value. " +
 "Expected the discarded bits to be zero.");
 }
 }

 void decode(final byte[] input, int inPos, final int inAvail, final Context context) {
 // package protected for access from I/O streams

 if (context.eof) {
 return;
 }
 if (inAvail < 0) {
 context.eof = true;
 }
 for (int i = 0; i < inAvail; i++) {
 final byte b = input[inPos++];
 if (b == pad) {
 // We're done.
 context.eof = true;
 break;
 }
 final byte[] buffer = ensureBufferSize(decodeSize, context);
 if (b >= 0 && b < this.decodeTable.length) {
 final int result = this.decodeTable[b];
 if (result >= 0) {
 context.modulus = (context.modulus + 1) % BYTES_PER_ENCODED_BLOCK;
 // collect decoded bytes
 context.lbitWorkArea = (context.lbitWorkArea << BITS_PER_ENCODED_BYTE) + result;
 if (context.modulus == 0) { // we can output the 5 bytes
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 32) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS);
 buffer[context.pos++] = (byte) (context.lbitWorkArea & MASK_8BITS);
 }
 }
 }
 }

 // Two forms of EOF as far as Base32 decoder is concerned: actual
 // EOF (-1) and first time '=' character is encountered in stream.
 // This approach makes the '=' padding characters completely optional.
 if (context.eof && context.modulus >= 2) { // if modulus < 2, nothing to do
 final byte[] buffer = ensureBufferSize(decodeSize, context);

 // we ignore partial bytes, i.e. only multiples of 8 count
 switch (context.modulus) {
 case 2: // 10 bits, drop 2 and output one byte
 validateCharacter(MASK_2BITS, context);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 2) & MASK_8BITS);
 break;
 case 3: // 15 bits, drop 7 and output 1 byte
 validateCharacter(MASK_7BITS, context);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 7) & MASK_8BITS);
 break;
 case 4: // 20 bits = 2*8 + 4
 validateCharacter(MASK_4BITS, context);
 context.lbitWorkArea = context.lbitWorkArea >> 4; // drop 4 bits
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS);
 break;
 case 5: // 25bits = 3*8 + 1
 validateCharacter(MASK_1BITS, context);
 context.lbitWorkArea = context.lbitWorkArea >> 1;
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS);
 break;
 case 6: // 30bits = 3*8 + 6
 validateCharacter(MASK_6BITS, context);
 context.lbitWorkArea = context.lbitWorkArea >> 6;
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS);
 break;
 case 7: // 35 = 4*8 +3
 validateCharacter(MASK_3BITS, context);
 context.lbitWorkArea = context.lbitWorkArea >> 3;
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 24) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 16) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea >> 8) & MASK_8BITS);
 buffer[context.pos++] = (byte) ((context.lbitWorkArea) & MASK_8BITS);
 break;
 default:
 // modulus can be 0-7, and we excluded 0,1 already
 throw new IllegalStateException("Impossible modulus " + context.modulus);
 }
 }
 }

 @Override
 protected boolean isInAlphabet(byte octet) {
 return octet >= 0 && octet < decodeTable.length && decodeTable[octet] != -1;
 }
 }
}

转发：nginx反向代理websocket返回403

Wed, 09 Feb 2022 14:06:00 +0000

原文：[Solution of nginx reverse proxy websocket response 403][1]

The log accessed through nginx has the following entry:

DEBUG ... o.s.w.s.s.s.OriginHandshakeInterceptor : Handshake request rejected, Origin header value https://some-host.com not allowed

Then Google queries related solutions to find the issue on GitHub, so you only need to modify the configuration of nginx and addproxy_set_header Origin “";That’s it.

http { //SSL related configuration

map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
server {
listen 8020;
location /ws {
proxy_pass http://some-ip:8080;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
proxy_set_header Origin "";
}
}

在我的access.log中并未发现关于“Origin”的信息，但是按照此方案修改配置文件后却可以解决问题。 [1]: https://developpaper.com/solution-of-nginx-reverse-proxy-websocket-response-403/

复习：StringBuilder和String拼接字符串效率差距真大

Sun, 23 Jan 2022 07:20:22 +0000

今天在解析一个5M的文本文件时，耗时两分多钟，找了半天才发现原因是使用String += s的方式拼接字符串导致的。

换成StringBuilder后速度提升了4个数量级！

至于原因，大家应该都懂，我就不再赘述了。 基础不能忘！！！ 基础不能忘！！！ 基础不能忘！！！

转载：一个好用的zip库zip4j

Sun, 23 Jan 2022 03:47:58 +0000

原文：[what-is-a-good-java-library-to-zip-unzip-files][1]

Demo：@user2003470

import net.lingala.zip4j.exception.ZipException;
import net.lingala.zip4j.core.ZipFile;


public static void unzip(){
 String source = "some/compressed/file.zip";
 String destination = "some/destination/folder";
 String password = "password";

 try {
 ZipFile zipFile = new ZipFile(source);
 if (zipFile.isEncrypted()) {
 zipFile.setPassword(password);
 }
 zipFile.extractAll(destination);
 } catch (ZipException e) {
 e.printStackTrace();
 }
}

The Maven dependency is:

<dependency>
 <groupId>net.lingala.zip4j</groupId>
 <artifactId>zip4j</artifactId>
 <version>1.3.2</version>
</dependency>

Ubuntu20.04中使用snap安装的docker如何修改registry-mirrors

Sun, 16 Jan 2022 14:24:43 +0000

如图：![cs.png][1]

通过 systemctl status snap.docker.dockerd.service 命令，可以找到daemon.json的路径

Ubuntu20.04中使用snap安装的docker如何开启远程访问？

Sun, 16 Jan 2022 13:32:00 +0000

转发：https://superuser.com/questions/1431826/expose-api-over-tcp-of-snap-installed-docker-on-ubuntu-18-04

@Rumdex

By running: systemctl status snap.docker.dockerd.service I was able to see which was the loaded service file: /etc/systemd/system/snap.docker.dockerd.service Just looked inside this file looking for the ExecStart directive. It was there. So just had to add -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock to that line, so it ended up looking like: ExecStart=/usr/bin/snap run docker.dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock Rebooted. Works.

文件名中出现^M导致java.io.FileNotFoundException

Tue, 16 Nov 2021 01:40:00 +0000

问题如图所示:

解决方案：vi filename打开文件，执行 : set ff=unix 设置文件为unix，然后执行:wq，保存成unix格式参考：https://blog.csdn.net/ygy162/article/details/105364096/

用多个密钥解密同一个密文

Tue, 21 Sep 2021 09:51:04 +0000

思想借鉴：https://www.zhihu.com/question/266180268

从严格意义上来说，这并不是某个加密算法，能够同时允许多个密钥解密。而是对称加密和非对称加密算法配合，实现将数据加密分发给多个人，能够让不同人使用自己的密钥解密数据

在线测试：Secret (caoxuan.top)

Demo（AES+RSA）:

package t20210921;

import util.AESUtil;
import util.RSAUtil;

import java.util.ArrayList;
import java.util.List;

/**
 * @author Cao Xuan
 * @date 2021/9/21 17:15
 */
public class Test {
 public static void main(String[] args) throws Exception {
 String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCrfQnSoLWLyob3d7PgZySgzRtAHCxyJaYs+Mqc2WeqwaxAlYV1vunmoadaVX00XzCqZej9HOxUbyxIJswrbKsK39mlj6LQ0VIVRngYgaYF5M7JsshiNnY0BCdmA39TzGtmdUDxppKQjyVT6MeUfqFO5NV9emWcrBKCad1Hql16AQIDAQAB";
 String privateKey = "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";
 String secretKey = "60479f43-b296-4199-8d97-de472e1d37bd";
 String plainText = "cxnb";
 String secretText = AESUtil.encrypt(plainText, secretKey);
 System.out.println("原文：" + plainText);
 System.out.println("密文：" + secretText);
 List<String> mySecretList = new ArrayList<>();
 for (int i = 0; i < 10; i++) {
 mySecretList.add(RSAUtil.encrypt(secretKey, publicKey));
 }
 System.out.println("多密钥" + mySecretList);
 mySecretList.forEach(e -> {
 System.out.println("使用密钥" + e + "解密");
 try {
 String s = AESUtil.decrypt(secretText, RSAUtil.decrypt(e, privateKey));
 System.out.println("解密成功" + s);
 } catch (Exception exception) {
 exception.printStackTrace();
 }
 });
 }
}

转发：mybatis 大坑之 useGeneratedKeys 返回值不是id，而是0跟1

Sun, 22 Aug 2021 07:46:07 +0000

> 打了断点一路追到底层，发现真tmd返回0跟1，后斜眼一看object的id改变了，妈的好神奇。

原文：https://blog.csdn.net/a5601564/article/details/77945958/

转发：mybatis报错：Error evaluating expression

Sat, 21 Aug 2021 15:45:54 +0000

解决方案：

解决：if标签的test里面的表达式的and不能写成大写AND。（具体的原因本人没有详细探究过，估计是mybatis的语法不允许吧）

原文：mybatis报错：Error evaluating expression

转发：Android Bitmap压缩图像的正确方法(compress的误区)

Sun, 15 Aug 2021 06:08:34 +0000

**摘要：**

Bitmap.compress方法确实可以压缩图片，但压缩的是存储大小，即你放到disk上的大小

我尝试过把品质设置为10，decode出来的Bitmap大小没变，但显示照片的质量非常差

BitmapFactory.decodeByteArray方法对压缩后的byte[]解码后，得到的Bitmap大小依然和未压缩过一样

如果你想要显示的Bitmap占用的内存少一点，还是需要去设置加载的像素长度和宽度（变成缩略图）

原文地址：https://blog.csdn.net/T3/article/details/79665077

Linux下使用jps命令报错

Sat, 14 Aug 2021 06:14:00 +0000

# 问题：Linux下使用jps命令报错java.lang.Error: Properties init: Could not determine current working directory.

![QQ截图20210814141543.png][1]

解决方案

![QQ截图20210814141703.png][2]

cd ..

发现是因为刚才在xftp中删除了此目录导致的![QQ截图20210814141831.png][3]

cd /

cd到根目录，再尝试使用jps，发现问题已解决 [1]: https://www.caoxuan.top/usr/uploads/2021/08/1556106767.png [2]: https://www.caoxuan.top/usr/uploads/2021/08/3988254530.png [3]: https://www.caoxuan.top/usr/uploads/2021/08/2498345376.png

好久没写了，随便水一贴吧

Tue, 20 Jul 2021 13:39:57 +0000

公元二〇二一年七月二十日星期二

六月十一辛丑年牛乙未月己巳日

2021/7/20

关于在Nginx中配置顶级域名与www域名之间跳转以及https和如何搭配CDN的综合解决方案

Tue, 04 May 2021 13:08:00 +0000

# 关于在Nginx中配置顶级域名与www域名之间跳转以及https和如何搭配CDN的综合解决方案

	方案一	方案二（不推荐）	方案三
使用场景	一般情况	顶级域名存在邮件服务	顶级域名存在邮件服务
相对复杂度	低	中	高
终点	`https://www.example.com`	`https://www.example.com`	`https://www.example.com`
隐藏源站IP	是	是	是
相对可用性	高	低	高
缺点	无法在顶级域名存在邮件服务的情况下使用	无法直接访问`https://example.com`	成本略高，配置麻烦
特殊要求	无	要求DNS服务商支持显性URL转发	需要一台代理服务器

方案一

源站配置（以Nginx为例）

关于www和naked域名的重新向以及https的解决方案（以Nginx为例） - 西叉的代码屋 (caoxuan.top)

CDN配置（以腾讯云为例）

基础配置

加速域名：www.example.com

源站类型：自有源

回源协议：协议跟随

源站地址：1.1.1.1（源站IP）

回源HOST：www.example.com

HTTPS配置

强制跳转

跳转配置：开

跳转类型：http->https

跳转方式：301跳转

携带头部：否

DNS配置（以阿里云为例）

记录类型	主机记录	解析线路	记录值	TTL
CNAME	www	默认	`www.example.com.cdn.dnsv1.com`（示例；实际以CDN控制台的为准）	10分钟
CNAME	@	默认	`www.example.com`	10分钟

路径表

起点	过程	浏览器请求次数
`http://example.com` 或 `example.com`	起点 -> CDN（301 `https://example.com`） `https://example.com` -> CDN -> 源站（301 `https://www.example.com`） `https://www.example.com` -> CDN -> 源站资源	3
`http://www.example.com` 或 `www.example.com`	起点 -> CDN（301 `https://www.example.com`） `https://www.example.com` -> CDN -> 源站资源	2
`https://example.com`	起点 -> CDN -> 源站（301 `https://www.example.com`） `https://www.example.com` -> CDN -> 源站资源	2
`https://www.example.com`	起点 -> CDN -> 源站资源	1

应急解决方案（保证可用性；前提：Nginx配置与本方案的源站配置相同）

SSL出现问题

步骤一：修改CDN的HTTPS配置

关闭强制跳转

关于www和naked域名的重新向以及https的解决方案（以Nginx为例）

Tue, 04 May 2021 10:55:00 +0000

以下是nginx的相关配置

#server1 http://example.com
server {
 listen 80;
 server_name example.com;
 return 301 http://www.example.com$request_uri;
}

#server2 http://www.example.com
server {
 listen 80;
 server_name www.example.com;
 return 301 https://$server_name$request_uri;
}

#server3 https://example.com
server {
 listen 443 ssl http2;
 server_name example.com;
 ssl_certificate 0000000_example.com.pem;
 ssl_certificate_key 0000000_example.com.key;
 ssl_session_cache shared:SSL:10m;
 ssl_session_timeout 10m;
 ssl_protocols TLSv1.2 TLSv1.3;
 return 301 https://www.example.com$request_uri;
}

#server4 https://www.example.com
server {
 listen 443 ssl ;
 server_name www.example.com;
 ssl_certificate 0000000_example.com.pem;
 ssl_certificate_key 0000000_example.com.key;
 ssl_session_cache shared:SSL:10m;
 ssl_session_timeout 10m;
 ssl_protocols TLSv1.2 TLSv1.3;
 location / {
 root /usr/share/nginx/html;
 index index.html index.htm;
 }
}

FAQs

Q：为什么要重定向多次？而不直接重定向到 https://www.example.com ？

A：为了降低出错后的维护成本，当ssl出现问题时，只需修改一个server（server2）即可以http的方式访问，从而恢复正常工作。

Q：这样做对SEO有影响吗？

A：鄙人才疏学浅，请自行查阅资料了解。目前看来，使用Google可以搜索到本站的内容，但是某度却不行。

fastjson反序列化后缺失属性值

Mon, 19 Apr 2021 15:09:00 +0000

**原因分析**：fastjson在反序列化时用的默认使用无参构造方法和getter与setter来构造对象，如果缺少无参构造方法，则会使用当前存在的构造方法（这个构造方法的参数可能不齐全）来构造对象。

解决方案：如果使用了Lombok，就在相应的实体类上添加注解*@NoArgsConstructor*；否则就手动重写无参构造方法。

RecyclerView只显示一条数据

Thu, 15 Apr 2021 08:26:10 +0000

![QQ截图20210415162531.png][1]

检查对应的item，将android:layout_height=“match_parent"改为android:layout_height=“wrap_content”。

简单实现负载均衡

Sun, 21 Mar 2021 15:03:00 +0000

```java

package algorithm.loadbalance;

import com.alibaba.fastjson.JSON;

import java.util.*;

/**

@author Cao Xuan
@date 2021/3/21 20:04
@update 2021/5/5 */ public class LoadBalanceDemo {

private final List serverList = new ArrayList<>();

/**
- client -> server */ private final Map<Client, Server> clientServerMap = new HashMap<>();
/**
- <—head—tail—>
- <—light—weight—>
- <—former—latter–> */ @Deprecated private void sort() { for (int i = serverList.size() - 1; i > 0; i–) { for (int j = i - 1; j > -1; j–) { Server latter = new Server(serverList.get(i)); Server former = new Server(serverList.get(j)); if (latter.getCurrentLoad().size() > former.getCurrentLoad().size()) { serverList.set(i, former); serverList.set(j, latter); } } } System.out.println(“sorting…”); }
/**
- <—head—tail—>
- <—light—weight—>
- <—former—latter–> */ private void leafShift() { int size = serverList.size(); for (int i = size - 2; i >= 0; i–) { Server latter = new Server(serverList.get(size - 1)); Server former = new Server(serverList.get(i)); if (latter.getCurrentLoad().size() > former.getCurrentLoad().size()) { serverList.set(size - 1, former); serverList.set(i, latter); System.out.println(“leaf shift”); } } }
private void rightShift(int index) { int size = serverList.size(); for (int i = index + 1; i < size; i++) { Server former = new Server(serverList.get(index)); Server latter = new Server(serverList.get(i)); if (former.getCurrentLoad().size() < latter.getCurrentLoad().size()) { serverList.set(i, former); serverList.set(index, latter); System.out.println(“right shift”); } } }

public Server addClient(Client client) { if (serverList.size() > 0) { Server server = new Server(serverList.get(serverList.size() - 1)); String serverName = server.getName(); serverList.get(serverList.size() - 1).updateCurrentLoad(client); System.out.println(“Hi,[” + client.getUsername() + “]. Assign [” + serverName + “] to you”); leafShift(); show(); return server; } else { System.err.println(“no server”); return null; } }

public void removeClient(String clientName) { Server server = clientServerMap.get(new Client(clientName)); int index = serverList.indexOf(server); if (-1 != index) { server.currentLoad.remove(new Client(clientName)); rightShift(index); System.out.println(“remove a client [” + clientName + “]”); } else { System.err.println(“index = -1”); }
```
 show();
```
}

public void addServer(String name) { Server server = new Server(name, new HashSet<>()); if (serverList.contains(server)) { System.err.println(“The server [” + name + “] already exists”); show(); return; } serverList.add(server); System.out.println(“add a server [” + name + “]”); show(); }

public void removeServer(String serverName) { serverList.remove(new Server(serverName)); System.out.println(“add a server [” + serverName + “]”); show(); }

private static class Client {
```
 private String username;
public Client(String username) {
this.username = username;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof Client)) {
return false;
}
Client client = (Client) obj;
return this.getUsername().equals(client.getUsername());
}
@Override
public int hashCode() {
return Objects.hash(username);
}
@Override
public String toString() {
return JSON.toJSONString(this);
}
```
}

private static class Server {
```
 private String name;
private Set<Client> currentLoad;
public Server(String name) {
this.name = name;
}
public Server(Server server) {
this.name = server.name;
this.currentLoad = server.currentLoad;
}
public Server(String name, Set<Client> currentLoad) {
this.name = name;
this.currentLoad = currentLoad;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<Client> getCurrentLoad() {
return currentLoad;
}
public void setCurrentLoad(Set<Client> currentLoad) {
this.currentLoad = currentLoad;
}
public void updateCurrentLoad(Client client) {
this.currentLoad.add(client);
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof Server)) {
return false;
}
Server server = (Server) obj;
return this.getName().equals(server.getName());
}
@Override
public String toString() {
return JSON.toJSONString(this);
}
```
}

public static void main(String[] args) {
```
 LoadBalanceDemo loadBalanceDemo = new LoadBalanceDemo();
System.out.println("---------------USAGE--------------");
System.out.println("Add a server: [s+${serverName}]");
System.out.println("Add a client: [c+${clientName}]");
System.out.println("Remove a server: [s-${serverName}]");
System.out.println("Remove a client: [c-${clientName}]");
System.out.println("Show Current Load: [show]");
System.out.println("---------------USAGE--------------");
while (true) {
System.out.println("ready");
System.out.println();
Scanner scanner = new Scanner(System.in);
String s = scanner.next();
if ("show".equals(s)) {
loadBalanceDemo.show();
} else if (s.startsWith("c+")) {
String clientName = s.substring(2);
Client client = new Client(clientName);
Server server = loadBalanceDemo.addClient(client);
loadBalanceDemo.clientServerMap.put(client, server);
} else if (s.startsWith("s+")) {
String serverName = s.substring(2);
loadBalanceDemo.addServer(serverName);
} else if (s.startsWith("c-")) {
String clientName = s.substring(2);
loadBalanceDemo.removeClient(clientName);
} else if (s.startsWith("s-")) {
String serverName = s.substring(2);
loadBalanceDemo.removeServer(serverName);
} else {
System.out.println("?");
}
System.out.println("----------------------------------");
}
```
}

private void show() { System.out.println(“current load " + serverList); } }

群晖 GitServer用户为空的解决办法

Fri, 26 Feb 2021 08:07:10 +0000

参考https://chaolucky.com/blog/12/03-927.html

sudo cp /var/packages/Git/target/webapi/SYNO.Git.lib /var/packages/Git/target/webapi/SYNO.Git.lib.bak sudo vi /var/packages/Git/target/webapi/SYNO.Git.lib 删掉appPriv 之后的SYNO.SDS.GIT.Instance 保存退出

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Thu, 17 Dec 2020 15:40:52 +0000

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关于在Nginx中配置顶级域名与www域名之间跳转以及https和如何搭配CDN的综合解决方案

方案一

源站配置（以Nginx为例）

CDN配置（以腾讯云为例）

基础配置

HTTPS配置

强制跳转

DNS配置（以阿里云为例）

路径表

应急解决方案（保证可用性；前提：Nginx配置与本方案的源站配置相同）

SSL出现问题

步骤一：修改CDN的HTTPS配置

关于www和naked域名的重新向以及https的解决方案（以Nginx为例）

FAQs

fastjson反序列化后缺失属性值

RecyclerView只显示一条数据

简单实现负载均衡

群晖 GitServer用户为空的解决办法

欢迎使用 Typecho

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