When applications based on struts2 and spring are idle for a period of time, a null pointer error is reported)

During struts2 and spring websites, after the system is idle for a period of time, an error will occur while accessing the page. The second visit will be normal. Later, I checked the background log and found that the database connection was closed, resulting in page access errors. A null pointer error is reported on the page. The error is not retained. The errors recorded in the log are as follows:

ERROR (java. SQL. Connection: 19)-Error calling Connection. close:
Java. SQL. SQLException: Already closed.
At org. apache. commons. dbcp. PoolableConnection. close (PoolableConnection. java: 84)
At org. apache. commons. dbcp. PoolingDataSource $ PoolGuardConnectionWrapper. close (PoolingDataSource. java: 181)
At org. springframework. jdbc. datasource. performanceutils. doReleaseConnection (performanceutils. java: 313)
At org. springframework. jdbc. datasource. transactionawareperformanceproxy $ TransactionAwareInvocationHandler. invoke (TransactionA
Wareperformanceproxy. java: 200)
At $ Proxy0.close (Unknown Source)
At sun. reflect. GeneratedMethodAccessor58.invoke (Unknown Source)
At sun. reflect. DelegatingMethodAccessorImpl. invoke (DelegatingMethodAccessorImpl. java: 25)
At java. lang. reflect. Method. invoke (Method. java: 585)
At com. ibatis. common. jdbc. logging. ConnectionLogProxy. invoke (ConnectionLogProxy. java: 68)
At $ Proxy1.close (Unknown Source)
At com. ibatis. sqlmap. engine. transaction. external. ExternalTransaction. close (ExternalTransaction. java: 82)
At com. ibatis. sqlmap. engine. transaction. TransactionManager. end (TransactionManager. java: 111)
At com. ibatis. sqlmap. engine. impl. SqlMapExecutorDelegate. endTransaction (SqlMapExecutorDelegate. java: 782)
At com. ibatis. sqlmap. engine. impl. SqlMapSessionImpl. endTransaction (SqlMapSessionImpl. java: 176)
At com. ibatis. sqlmap. engine. impl. SqlMapClientImpl. endTransaction (SqlMapClientImpl. java: 154)
At com. ibatis. sqlmap. engine. impl. SqlMapExecutorDelegate. autoEndTransaction (SqlMapExecutorDelegate. java: 883)
At com. ibatis. sqlmap. engine. impl. SqlMapExecutorDelegate. queryForList (SqlMapExecutorDelegate. java: 622)
At com. ibatis. sqlmap. engine. impl. SqlMapExecutorDelegate. queryForList (SqlMapExecutorDelegate. java: 589)
At com. ibatis. sqlmap. engine. impl. SqlMapSessionImpl. queryForList (SqlMapSessionImpl. java: 118)
At com. ibatis. sqlmap. engine. impl. SqlMapClientImpl. queryForList (SqlMapClientImpl. java: 95)
At com. wangar. ptc. dao. ibatis. IbatisSysMenuDAO. querySysMenuList (IbatisSysMenuDAO. java: 50)
At com. wangar. ptc. dao. impl. DefaultSysMenuDAO. querySysMenuList (DefaultSysMenuDAO. java: 22)
At com. wangar. ptc. manager. impl. DefaultSysMenuManager. querySysMenuList (defasyssysmenumanager. java: 187)
At com. wangar. ptc. manager. impl. DefaultSysMenuManager. querySysMenuBySmid (defasyssysmenumanager. java: 146)
At com. wangar. ptc. manager. impl. DefaultSysMenuManager. getRootSysMenu (defasyssysmenumanager. java: 90)
At com. wangar. ptc. ao. impl. DefaultSysMenuAO. getRootSysMenu (DefaultSysMenuAO. java: 50)
At com. wangar. ptc. action. IndexAction. mainIndex (IndexAction. java: 26)
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 com. opensymphony. xwork2.defaactionactioninvocation. invokeAction (DefaultActionInvocation. java: 441)
At com. opensymphony. xwork2.DefaultActionInvocation. invokeActionOnly (DefaultActionInvocation. java: 280)
At com. opensymphony. xwork2.defaactionactioninvocation. invoke (defaactionactioninvocation. java: 243)
At com. opensymphony. xwork2.interceptor. DefaultWorkflowInterceptor. doIntercept (defaworkworkflowinterceptor. java: 165)
At com. opensymphony. xwork2.interceptor. MethodFilterInterceptor. intercept (MethodFilterInterceptor. java: 87)
At com. opensymphony. xwork2.defaactionactioninvocation. invoke (defaactionactioninvocation. java: 237)
At com. opensymphony. xwork2.validator. ValidationInterceptor. doIntercept (ValidationInterceptor. java: 252)
At org. apache. struts2.interceptor. validation. AnnotationValidationInterceptor. doIntercept (AnnotationValidationInterceptor. jav
A: 68)

...... Omitting some errors ......

When I saw the error, I thought it was because the data connection was not used for a long time and I closed it myself. So I first thought of starting with the data source configuration parameters, and then I searched for it, I see someone has encountered the same problem. I will post the content here first. I used apache dbcp data in spring for database connection. The configuration code is as follows:

Jdbc. driver = com. mysql. jdbc. Driver
Jdbc. url = jdbc: mysql: // localhost: 3306/database
Jdbc. username = user
Jdbc. password = usr
Data source configuration
<Bean id = "dataSource" class = "org. apache. commons. dbcp. BasicDataSource">
<Property name = "driverClassName" value = "$ {jdbc. driver}"/>
<Property name = "url" value = "$ {jdbc. url}"/>
<Property name = "username" value = "$ {jdbc. username}"/>
<Property name = "password" value = "$ {jdbc. password}"/>
</Bean>


# Verify the connection
Jdbc. testOnBorrow = true



The blue bold part mainly solves the problem of automatic database reconnection.

Original article: http://blog.sina.com.cn/s/blog_655c5e7b0100h9iu.html