mysql长时间没有响应后到达timeout时间连接就中断了.错误代码如下._习惯累积沉淀

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本文记录了一次MySQL连接异常的问题排查过程。主要问题是由于服务器连接超时导致的MySQLNonTransientConnectionException异常，通过调整服务器配置及客户端设置成功解决了问题。

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com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed.

at sun.reflect.GeneratedConstructorAccessor3.newInstance(Unknown Source)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)

at com.mysql.jdbc.Util.getInstance(Util.java:386)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)

at com.mysql.jdbc.ConnectionImpl.throwConnectionClosedException(ConnectionImpl.java:1304)

at com.mysql.jdbc.ConnectionImpl.checkClosed(ConnectionImpl.java:1296)

at com.mysql.jdbc.ConnectionImpl.createStatement(ConnectionImpl.java:2676)

at com.mysql.jdbc.ConnectionImpl.createStatement(ConnectionImpl.java:2658)

at db.Dao.insertAll(Dao.java:50)

at file.unzip.FileReader.readFileWriteDb(FileReader.java:217)

at main.GetData.run(GetData.java:49)

at main.GetData.main(GetData.java:67)

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 50,332,352 milliseconds ago. The last packet sent successfully to the server was 50,332,345 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)

at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)

at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3673)

at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3562)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4113)

at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2570)

at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2731)

at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2812)