The last packet successfully received from the server was 20 milliseconds ago. 问题排查

原创已于 2022-05-02 14:34:43 修改 · 2.5k 阅读

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于 2022-05-02 14:33:15 首次发布

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本文分析了在启动Spring Boot应用时遇到的数据库连接错误，指出MySQL useSSL=true导致的问题，并提供了将useSSL设置为false的解决方法，以确保与SSL连接的正确配置。

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今天启动ideal 打开本地项目报错，如下：
The last packet successfully received from the server was 20 milliseconds ago. The last packet sent successfully to the server was 20 milliseconds ago.
   at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:324) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1378) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:575) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$106/10041107.getObject(Unknown Source) ~[na:na]
   at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846) ~[spring-beans-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) ~[spring-context-5.1.3.RELEASE.jar:5.1.3.RELEASE]
   at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) ~[spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.1.RELEASE.jar:2.1.1.RELEASE]
   at com.yawn.ActivitiDemo6SpringbootApplication.main(ActivitiDemo6SpringbootApplication.java:17) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'identityServiceBean' defined in class path resource [org/activiti/spring/boot/DataSourceProcessEngineAutoConfiguration$DataSourceProcessEngineConfiguration.class]: Unsatisfied dependency expressed through method 'identityServiceBean' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'processEngine': FactoryBean threw exception on object creation; nested exception is org.activiti.engine.ActivitiException: couldn't check if tables are already present using metadata: Communications link failure

这个报错是链接mysql数据库报错，翻看网上好多文章，有说是修改my.ini文件，延长数据库超时时间（结果证明没用）；有说连接错误的数据库，数据库不存在（结果也不是）。

真正的原因分析：

先看看mysql数据库连接

这里有个useSSL=true的参数，MySQL在高版本需要指明是否进行SSL连接。

SSL协议提供服务主要：
1）认证用户服务器，确保数据发送到正确的服务器；　　 .
2）加密数据，防止数据传输途中被窃取使用；
3）维护数据完整性，验证数据在传输过程中是否丢失；
当前支持SSL协议两层：
SSL记录协议（SSL Record Protocol）：建立靠传输协议（TCP）高层协议提供数据封装、压缩、加密等基本功能支持
SSL握手协议（SSL Handshake Protocol）：建立SSL记录协议用于实际数据传输始前通讯双进行身份认证、协商加密
算法、交换加密密钥等。

不建议在没有服务器身份验证的情况下建立SSL连接。根据MySQL 5.5.45+、5.6.26+和5.7.6+的要求，如果不设置显式选项，则必须建立默认的SSL连接。需要通过设置useSSL=false来显式禁用SSL，或者设置useSSL=true并为服务器证书验证提供信任存储。

所以建议设置useSSL为false.