Mysql: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

2019-05-28 01:53:42.762 [message remind thread-24] ERROR druid.sql.Statement - {conn-10327, stmt-32027} execute error. SELECT 1 FROM DUAL
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 5,348,934 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
at sun.reflect.GeneratedConstructorAccessor85.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:2483)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2441)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1381)
at com.alibaba.druid.filter.FilterChainImpl.statement_executeQuery(FilterChainImpl.java:2363)
at com.alibaba.druid.filter.FilterAdapter.statement_executeQuery(FilterAdapter.java:2481)
at com.alibaba.druid.filter.FilterEventAdapter.statement_executeQuery(FilterEventAdapter.java:302)
at com.alibaba.druid.filter.FilterChainImpl.statement_executeQuery(FilterChainImpl.java:2360)
at com.alibaba.druid.filter.FilterAdapter.statement_executeQuery(FilterAdapter.java:2481)
at com.alibaba.druid.filter.FilterEventAdapter.statement_executeQuery(FilterEventAdapter.java:302)
at com.alibaba.druid.filter.FilterChainImpl.statement_executeQuery(FilterChainImpl.java:2360)
at com.alibaba.druid.proxy.jdbc.StatementProxyImpl.executeQuery(StatementProxyImpl.java:211)
at com.alibaba.druid.pool.ValidConnectionCheckerAdapter.isValidConnection(ValidConnectionCheckerAdapter.java:44)
at com.alibaba.druid.pool.DruidAbstractDataSource.testConnectionInternal(DruidAbstractDataSource.java:1298)
at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:1054)
at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4544)
at com.alibaba.druid.filter.logging.LogFilter.dataSource_getConnection(LogFilter.java:831)
at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4540)
at com.alibaba.druid.filter.stat.StatFilter.dataSource_getConnection(StatFilter.java:662)
at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:4540)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:992)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:984)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:103)
at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:246)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373)
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:461)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:277)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy119.insert(Unknown Source)
at com.lolaage.cmm.thread.YjInfoHandleThread$WorkThread.run(YjInfoHandleThread.java:72)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3011)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3469)
... 37 common frames omitted

===> 客户端使用的连接已经关闭了。

1.检查是否有设置定期检查空闲连接
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false

2.检查数据库中的wait_timeout
show global variables like 'wait_timeout';
show global variables like 'interactive_timeout';
如果数据库中wait_timeout小于客户端代码中maxEvictableIdleTimeMillis的值，也会导致客户端使用时，出现已经关闭的连接。