tomcat + mysql 空闲时间长后(一两天)就会失去和数据库的连接

Caused by: java.sql.SQLException: Communication link failure: java.net.SocketException, underlying cause: Software caused connection abort: socket write error** BEGIN NESTED EXCEPTION ** java.net.SocketException
MESSAGE: Software caused connection abort: socket write errorSTACKTRACE:java.net.SocketException: Software caused connection abort: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:1764)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:1727)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1148)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1278)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2247)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1586)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(Unknown Source)
at org.hibernate.loader.Loader.getResultSet(Unknown Source)
at org.hibernate.loader.Loader.doQuery(Unknown Source)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Unknown Source)
at org.hibernate.loader.Loader.doList(Unknown Source)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Unknown Source)
at org.hibernate.loader.Loader.list(Unknown Source)
at org.hibernate.loader.hql.QueryLoader.list(Unknown Source)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(Unknown Source)
at org.hibernate.engine.query.HQLQueryPlan.performList(Unknown Source)
at org.hibernate.impl.SessionImpl.list(Unknown Source)
at org.hibernate.impl.QueryImpl.list(Unknown Source)
at com.parent51.dao.DAO.executeNamedQuery(DAO.java:394)
at com.parent51.dao.CepingDAO.getCPComment(CepingDAO.java:164)
at com.parent51.action.ScaleindexAction.indexScale(ScaleindexAction.java:65)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:270)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:187)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at com.parent51.servlet.XDL_ActionServlet.process(XDL_ActionServlet.java:116)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at com.parent51.servlet.XDL_HibernateFilter.doFilter(XDL_HibernateFilter.java:73)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.cluster.tcp.ReplicationValve.invoke(ReplicationValve.java:141)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at com.parent51.util.HostFilter.invoke(HostFilter.java:187)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:300)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:374)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:743)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:675)
at org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:866)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:595)
** END NESTED EXCEPTION **
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:1785)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:1727)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1148)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1278)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2247)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1586)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(Unknown Source)
at org.hibernate.loader.Loader.getResultSet(Unknown Source)
at org.hibernate.loader.Loader.doQuery(Unknown Source)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Unknown Source)
... 57 more