MySQL--解决CommunicationsException: Communications link failure-蒲公英云

MySQL--解决CommunicationsException: Communications link failure

港控/mmm° 2023-10-01 18:50 150阅读 0赞

原文网址：MySQL—解决CommunicationsException: Communications link failure_IT利刃出鞘的博客-CSDN博客

简介

说明

本文介绍Java中操作MySQL时一个报错的原因及解决方案。这个报错是：com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

完整报错信息

2022-02-16 08:03:00 [WARN] [com.zaxxer.hikari.pool.ProxyConnection:160] - HikariPool-1 - Connection com.mysql.jdbc.JDBC4Connection@1f2bca8b marked as broken because of SQLSTATE(08S01), ErrorCode(0)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 60,061 milliseconds ago.  The last packet sent successfully to the server was 60,060 milliseconds ago.
        at sun.reflect.GeneratedConstructorAccessor305.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
        at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:989)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3559)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3459)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3900)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2487)
        at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
        at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
        at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
        at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
        at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)
        at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61)
        at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java)
        at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204)
        ... 74 common frames omitted

原因分析

导致这个报错的原因有两个

数据库重启
客户端长时间没操作数据库（数据库空闲连接的时间超过设置的最大timemout时间）
1. 导致数据库会强行断开已有的链接，就会报这个异常。

对于第二个原因（客户端长时间没操作数据库）

MySQL服务器默认的“wait_timeout”是28800秒，即：8小时。这意味着如果一个连接的空闲时间超过8个小时，MySQL将自动断开该连接，而客户端连接池却认为该连接还是有效的(因为并未校验连接的有效性)，当客户端申请使用该连接时，就会导致上面的报错。

查看MySQL的wait_timeout的方法：

mysql > show global variables like 'wait_timeout'; 
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 28800 |
+---------------+-------+
1 row in set (0.00 sec)