RT !
SpringBoot + Druid + Hibernate
configuration：
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
url: ****
username: root
password: ****
driverClassName: com.mysql.jdbc.Driver
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
removeAbandoned: false
removeAbandonedTimeout: 300
logAbandoned: true
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000作用
validationQuery: SELECT 1
testWhileIdle: true
testOnBorrow: true
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat
console：
15:43:03.306 [http-nio-8080-exec-5] ERROR com.alibaba.druid.pool.DruidDataSource - discard connection
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 74,907 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
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:404)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:988)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3552)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3452)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3893)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1962)
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_executeQuery(FilterChainImpl.java:2714)
at com.alibaba.druid.filter.FilterEventAdapter.preparedStatement_executeQuery(FilterEventAdapter.java:465)
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_executeQuery(FilterChainImpl.java:2711)
at com.alibaba.druid.proxy.jdbc.PreparedStatementProxyImpl.executeQuery(PreparedStatementProxyImpl.java:145)
at com.alibaba.druid.pool.DruidPooledPreparedStatement.executeQuery(DruidPooledPreparedStatement.java:227)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:70)
at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.getResultSet(AbstractLoadPlanBasedLoader.java:434)
at org.hibernate.loader.plan.exec.internal.AbstractLoadPlanBasedLoader.executeQueryStatement(AbstractLoadPlanBasedLoader.java:186)
...
...
...
na.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:107)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
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:3004)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3462)
... 194 common frames omitted
15:43:03.313 [http-nio-8080-exec-5] WARN org.hibernate.engine.jdbc.spi.SqlExceptionHelper - SQL Error: 0, SQLState: 08S01
15:43:03.319 [http-nio-8080-exec-5] ERROR org.hibernate.engine.jdbc.spi.SqlExceptionHelper - Communications link failure
The last packet successfully received from the server was 74,907 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.
...
