hibernate 使用连接池连接数据库时 自动断开处理

项目中使用c3p0连接数据库里 ,每隔一段时间就报以下错误:

JDBC begin failed [ERROR] 2011-05-08 01:56:33com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.SocketExceptionMESSAGE: Connection timed outSTACKTRACE:java.net.SocketException: Connection timed outat java.net.SocketOutputStream.socketWrite0(Native Method)at java.net.SocketOutputStream.socketWrite(Unknown Source)at java.net.SocketOutputStream.write(Unknown Source)at java.io.BufferedOutputStream.flushBuffer(Unknown Source) 

..................

at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)at java.lang.Thread.run(Unknown Source)Caused by: org.hibernate.TransactionException: JDBC begin failed: at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:68)at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1326)at org.springframework.orm.hibernate3.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:558)... 89 moreCaused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:  

错误内容太多 ,中间省略很大一部分..

 

datasource配置:

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"destroy-method="close"><property name="driverClass" value="com.mysql.jdbc.Driver"></property><property name="minPoolSize" value="20"></property><property name="initialPoolSize" value="25"></property><property name="maxPoolSize" value="100"></property><property name="maxStatements" value="200"></property><property name="maxStatementsPerConnection" value="200"></property><property name="acquireIncrement" value="3"></property><property name="acquireRetryAttempts" value="10"></property><property name="autoCommitOnClose" value="false"></property><property name="acquireRetryDelay" value="2000"></property><property name="maxIdleTimeExcessConnections" value="50"></property><property name="maxIdleTime" value="86400000"></property><property name="automaticTestTable" value="c3p0_test"></property><property name="breakAfterAcquireFailure" value="false"></property><property name="jdbcUrl"value="${jdbc.url}?setUnicode=true&characterEncoding=utf8"></property><property name="user" value="${jdbc.username}"></property><property name="password" value="${jdbc.password}"></property></bean> 

 

几经周折,发现使用的mysql数据库有一个系统参数为

wait-timeout  The number of seconds the server waits for activity on a noninteractive connection before closing it.

看网上说的默认时间是8小时(但是我使用的mysql版本配置文件中没有发现有此属性配置,也不知道默认的是不是8小时,姑且当作是),所以在连接池配置中添加了以下配置不再出现异常:

<property name="idleConnectionTestPeriod" value="60"></property>

注意此时间要小于数据库配置的空闲等待时间