SQL Error: 0, SQLState: 08S01
[2007-11-20 09:14:30] 72 ERROR [org.hibernate.util.JDBCExceptionReporter]
Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.SocketException
MESSAGE: Broken pipe

STACKTRACE:

java.net.SocketException: Broken pipe
 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:2637)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1554)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:3176)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1153)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1266)
 at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:120)
 at org.hibernate.loader.Loader.getResultSet(Loader.java:1272)
 at org.hibernate.loader.Loader.doQuery(Loader.java:391)
 at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:218)
 at org.hibernate.loader.Loader.loadEntity(Loader.java:1345)
 at org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:116)
 at org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:101)
 at org.hibernate.persister.entity.BasicEntityPersister.load(BasicEntityPersister.java:2471)
 at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:351)
 at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:332)
 at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:113)
 at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:151)
 at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:79)
 at org.hibernate.impl.SessionImpl.get(SessionImpl.java:621)
 at org.hibernate.impl.SessionImpl.get(SessionImpl.java:614)
 at com.cotel.dao.BaseDao.getObject(BaseDao.java:180)
 at com.cotel.wfsgprs.bean.systemmanage.LoginBean.login(LoginBean.java:61)
 at com.cotel.wfsgprs.struts.action.login.LoginAction.login(LoginAction.java:70)
 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:280)
 at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:216)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
 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 org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:704)
 at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:474)
 at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:409)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312)
 at com.cotel.util.ValidationFilter.doFilter(ValidationFilter.java:60)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
 at com.cotel.util.PagingFilter.doFilter(PagingFilter.java:42)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
 at com.cotel.util.EncodingFilter.doFilter(EncodingFilter.java:28)
 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.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 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.coyote.http11.Http11Processor.process(Http11Processor.java:799)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
 at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
 at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
 at java.lang.Thread.run(Thread.java:595)

** END NESTED EXCEPTION **

       后會自動關閉已打開的連接，再問了一下，他們用的不是c3p0的數據源，建議他們改成c3p0的數據源，明天就能看到是不是由于這個原因引起的，特此記錄。
       找到解決方案的一篇文章：http://wooce.sharera.com/blog/BlogTopic/35599.htm
       該問題的解決方案摘錄如下：
       06/05/15:
Q:  用hibernate + mysql數據庫， 出現以下問題： 
Communication link failure: java.net.SocketException, underlying cause: Broken pipe: Broken pipe 
** BEGIN NESTED EXCEPTION ** java.net.SocketException MESSAGE: Broken pipe: Broken pipe 
STACKTRACE: java.net.SocketException: Broken pipe: Broken pipe
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:116)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:183)
at java.io.BufferedInputStream.read(BufferedInputStream.java:201)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:1399)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1775)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1020)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1109)
at com.mysql.jdbc.MysqlIO.sqlQuery(MysqlIO.java:1070)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2027)
at com.mysql.jdbc.Connection.execSQL(Connection.java:1984)
at com.mysql.jdbc.Statement.executeQuery(Statement.java:1152) 
A:   
1.  Mysql在經過8小時不使用后會自動關閉已打開的連接，摘錄原文如下： 
I have a servlet/application that works fine for a day, anｄ then stops working overnight 
MySQL closes connections after 8 hours of inactivity. You either need to use a connection pool that handles stale connections oｒ use the "autoReconnect" parameter (see "Developing Applications with MySQL Connector/J").

Also, you should be catching SQLExceptions in your application anｄ dealing with them, rather than propagating them all the way until your application exits, this is just good programming practice. MySQL Connector/J will set the SQLState (see java.sql.SQLException.getSQLState() in your APIDOCS) to "08S01" when it encounters network-connectivity issues during the processing of a query. Your application code should then attempt to re-connect to MySQL at this point.
2.  Should the driver try to re-establish stale oｒ dead connections? If enabled the driver will throw an exception for a queries issued on a stale oｒ dead connection, which belong to the current transaction, but will attempt reconnect before the next query issued on the connection in a new transaction. The use of this feature is not recommended, because it has side effects related to session state anｄ data consistency when applications don'thandle SQLExceptions properly, anｄ is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead andstale connections properly. Alternatively, investigate setting the MySQL wait_timeout system variable to some high value rather than the default of 8 hours.

http://dev.mysql.com/doc/refman/5.0/en/cj-configuration-properties.html

好象用了autoReconnect以后會自動重新連接的
雖然第一次執行失敗了，
但是以后會自動重新連接的
3.  在這個頁面找到了第三種方法，即不使用Hibernate內置的連接池（Hibernate強烈推薦不使用但我以前一直在用），改用C3P0連接池，這個連接池會自動處理數據庫連接被關閉的情況。要使用C3P0很簡單，先從Hibernate里把c3p0-0.8.3.jar復制到項目的lib目錄中，再在hibernate.properties里去掉hibernate.c3p0開頭的那些屬性的注釋（使用缺省值或自己需要的數值），這樣Hibernate就會自動使用C3P0代替內置的連接池了。到目前為止前面的問題沒有再出現過。

以前對Hibernate警告不要使用內置連接池作產品用途沒有太放在心上，這次是一個教訓，所以不論從穩定還是性能的考慮，都應該選擇相對更加成熟的連接池。
4.  在服務器上過期的‘Wait—timeout’基本上是服務器給與的強制性網絡故障。你通過把‘Wait—timeout’設置的高點兒就可以改正它，盡管如此，作為一個開發者，你的代碼應該包含相關的異常處理并采取適當的恢復措施，不要都把它們傳到調用堆中。

    在轉貼一下在hibernate中設置c3p0數據源的方法，原文地址：http://www.lifevv.com/tenyo/doc/20070605102040991.html
     內容如下：
    c3p0為open source的JDBC連接池，隨hibernate一起發布。本文介紹了怎么在hibernate里配置使用c3p0。

c3p0連接池的配置非常簡單，只需要在hibernate.cfg.xml里增加：         <!-- configuration pool -->         <property name="c3p0.acquire_increment">1</property>         <property name="c3p0.idle_test_period">100</property> <!-- seconds -->         <property name="c3p0.max_size">5</property>         <property name="c3p0.max_statements">0</property>         <property name="c3p0.min_size">2</property>         <property name="c3p0.timeout">90</property> <!-- seconds --> 另外，還需要在CLASS_PATH里加上c3p0-x.x.x.jar文件（x.x.x為版本號），c3p0-x.x.x.jar文件隨hibernate一起發布，你可以在其lib目錄下找到該文件。 配置好之后，hibernate便會自動使用c3p0的連接池：C3P0ConnectionProvider