急！！The last packet sent successfully to the server was 0 milliseconds ago.的问题

[feiyuxiaoxiao]

一个Flex+J2EE的项目，用的是eclipse3.4，Spring+Hibernate架构，mysql5.1数据库。
项目是在实验室的台式机上开发的，笔记本只是在项目开始的时候配置好了环境，距现在已经将近一年了，现在要用笔记本进行演示，可是出现了这个问题：

18:58:52,151  WARN SettingsFactory:137 - Could not obtain connection to query metadata
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2214)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:781)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:352)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:284)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133)
	at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:114)
	at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2163)
	at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2159)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1383)
	at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:855)
	at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:774)
	at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1460)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1400)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:450)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:290)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:287)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:545)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:871)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:423)
	at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:272)
	at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:196)
	at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:47)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3830)
	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4337)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:920)
	at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:883)
	at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
	at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
	at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
	at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
	at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
	at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
	at org.apache.catalina.core.StandardService.start(StandardService.java:516)
	at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:566)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

在网上查了好久，大部分是说mysql的间隔访问时间太长导致的，但是，我的系统是前段时间重新安装的，数据库自然也是重新安装的，eclipse是绿色版的软件，里面直接集成的Flex，我在台式机上把eclipse文件夹拷贝到笔记本上，无论怎么调试也都是这个结果，求求各位路过的大神帮帮忙，看看到底是怎么回事啊
mysql的url没有配置错误：jdbc:mysql://localhost/accountsystem
我都快急死了，演示在即，希望大家帮帮忙吧

[戰之樂章]

解决方法： （1）使用JDBC URL中使用autoReconnect属性，url添加&autoReconnect=true&failOverReadOnly=false （2） 修改MySQL的参数. /etc/my.cnf 添加 [mysqld] wait_timeout=31536000 interactive_timeout=31536000 （3）重启mysql service mysql restart 原因分析： （1）大量数据访问情况下，mysql connection连接有可能失效 （2）长时间不妨问，connection会失效