生产环境应用无法创建数据库连接问题解决 The driver has not received any packets from the server-优快云博客

本文链接：https://blog.youkuaiyun.com/zhang_yyii1/article/details/101029378

本文档详细介绍了在生产环境中遇到的应用无法创建数据库连接的问题，特别是关于'The driver has not received any packets from the server'的错误。通过分析问题，提出了解决方案，包括在MySQL JDBC URL中设置`autoReconnect=true`，调整MySQL的`wait_timeout`和`interactive_timeout`参数，以及优化Druid连接池配置，如设置`testOnBorrow=true`以确保连接有效性。

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生产环境应用无法创建数据库连接问题解决 The driver has not received any packets from the server

背景：
业务小伙伴报告系统页面打不开进不去，无法正常操作；
遂查看日志

一、问题

以下是log

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.GeneratedConstructorAccessor245.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2214)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:781)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor93.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:352)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:284)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:156)
	at com.alibaba.druid.filter.FilterAdapter.connection_connect(FilterAdapter.java:787)
	at com.alibaba.druid.filter.FilterEventAdapter.connection_connect(FilterEventAdapter.java:38)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:150)
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:150)
	at com.alibaba.druid.filter.stat.StatFilter.connection_connect(StatFilter.java:218)
	at com.alibaba.druid.filter.FilterChainImpl.connection_connect(FilterChainImpl.java:150)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1598)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1662)
	at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2601)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

数据库无法创建新连接可以看到这一句：The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

这个报错的含义是mysql连接超时了。

二、解决方案

mysql版本5.x之前可以在jdbcurl后面设置 autoReconnect=true

jdbc.url=jdbc:mysql://192.168.0.1:3306/test?useUnicode=true&characterEncoding=utf8&autoReconnect=true&failOverReadOnly=false

设置mysql wait_timeout
默认mysql的 ‘wait_timeout’ 是8小时；28800秒

set global wait_timeout=86400;
set global interactive_timeout=86400;