java.net.SocketException: Broken pipe 解决

网上关于java.net.SocketException: Broken pipe 这个原因分析很多，我当前遇到的情况是因为数据库wait_timeout时间过短，引起的链接关闭

异常

SEVERE: Servlet.service() for servlet [cas] in context with path [/manage/cas] threw exception [Request processing failed; nested exception is org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [AnnotatedAction@38835551 targetAction = [EvaluateAction@365655d3 expression = authenticationViaFormAction.submit(flowRequestContext, flowScope.credentials, messageContext), resultExpression = [null]], attributes = map[[empty]]] in state 'realSubmit' of flow 'login' -- action execution attributes were 'map[[empty]]'] with root cause
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:3329)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1967)
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2140)
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2620)
	at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5022)
	at org.apache.tomcat.dbcp.dbcp.DelegatingConnection.setAutoCommit(DelegatingConnection.java:371)
	at org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.setAutoCommit(PoolingDataSource.java:328)
	at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:223)
	at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at com.sun.proxy.$Proxy20.createTicketGrantingTicket(Unknown Source)
	at org.jasig.cas.web.flow.AuthenticationViaFormAction.submit(AuthenticationViaFormAction.java:109)
	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:597)
	at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:851)
	at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1253)
	at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
	at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1329)
	at ognl.ASTMethod.getValueBody(ASTMethod.java:90)
	at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
	at ognl.SimpleNode.getValue(SimpleNode.java:258)
	at ognl.ASTChain.getValueBody(ASTChain.java:141)
	at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
	at ognl.SimpleNode.getValue(SimpleNode.java:258)
	at ognl.Ognl.getValue(Ognl.java:494)

解决方案：
修改mysql的wait_timeout时间

mysql>show variables like '%timeout%';//查询会话变量

mysql>set wait_timeout=388000; //默认为28800
mysql>set interactive_timeout=388000; //默认为28800

1、这里设置的是会话变量，全局变量的设置需要增加global，如果避免重启失效，还需要在/ect/my.cnf中的mysqld增加相应配置项，全局变量这两个值不易设置过大，最好根据业务来设置，过大意味着暂用内存较大，因为链接得不到释放（最大连接数max_connections）

2、wait_timeout和interactive_timeout需要同时设置，否则会出现互相覆盖的情况
(1)interactive_timeout:
参数含义：服务器关闭交互式连接前等待活动的秒数。交互式客户端定义为在mysql_real_connect()中使用CLIENT_INTERACTIVE选项的客户端。
参数默认值：28800秒（8小时）

(2)wait_timeout:
参数含义：服务器关闭非交互连接之前等待活动的秒数。
在线程启动时，根据全局wait_timeout值或全局interactive_timeout值初始化会话wait_timeout值，取决于客户端类型(由mysql_real_connect()的连接选项CLIENT_INTERACTIVE定义)。
参数默认值：28800秒（8小时）


3、另外当会话变量小于全局变量时，如果在设定的时间没有链接，再次链接数据库会报如下错误

ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id:    17
Current database: *** NONE ***

并且将全局变量值设置为会话变量，所以会话变量的设置一定要大于全局变量




延伸：
mysql wait_timeout和interactive_timeout总结 
http://blog.csdn.net/z1988316/article/details/7976038

MySQL数据库连接超时(wait_timeout)问题的处理
http://sarin.iteye.com/blog/580311/

会话变量与全局变量
http://www.2cto.com/database/201312/261593.html