Java代码

1. <filter>   
2.         <filter-name>JAMonFilter</filter-name>   
3.         <filter-class>com.easywebwork.filter.EasyPageMonFilter</filter-class>   
4.     </filter>   
5.     <filter-mapping>   
6.         <filter-name>JAMonFilter</filter-name>   
7.         <url-pattern>/*</url-pattern>   
8.     </filter-mapping>  

<filter>
<filter-name>JAMonFilter</filter-name>
<filter-class>com.easywebwork.filter.EasyPageMonFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>JAMonFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

Java代码

1. /**  
2.  * @author 张荣华（ahuaxuan）  
3.  *  
4.  * @since 2007-8-13  
5.  */  
6. public class PageMonFilter extends JAMonFilter{   
7.   
8.     private static final long serialVersionUID = 5746197114960908454L;   
9.   
10.     public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {   
11.          Monitor allPages = MonitorFactory.start(new MonKeyImp("org.easywebwork.allPages",getURI(request),"ms."));   
12.          //这里就是我们要监视的所有的页面的配置   
13.          Monitor monitor = MonitorFactory.start(getURI(request));   
14.          //这里就是我们要监视的某个页面的配置   
15.          try {   
16.           filterChain.doFilter(request, response);   
17.          } finally {   
18.           monitor.stop();   
19.           allPages.stop();   
20.          }   
21.        }   
22.   
23.        protected String getURI(ServletRequest request) {   
24.          if (request instanceof HttpServletRequest) {   
25.            return ((HttpServletRequest) request).getRequestURI();   
26.          }  else {   
27.            return "Not an HttpServletRequest";   
28.          }   
29.        }   
30.   
31.        private FilterConfig filterConfig = null;   
32.           
33. }}  

/**
* @author 张荣华（ahuaxuan）
*
* @since 2007-8-13
*/
public class PageMonFilter extends JAMonFilter{
private static final long serialVersionUID = 5746197114960908454L;
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
Monitor allPages = MonitorFactory.start(new MonKeyImp("org.easywebwork.allPages",getURI(request),"ms."));
//这里就是我们要监视的所有的页面的配置
Monitor monitor = MonitorFactory.start(getURI(request));
//这里就是我们要监视的某个页面的配置
try {
filterChain.doFilter(request, response);
} finally {
monitor.stop();
allPages.stop();
}
}
protected String getURI(ServletRequest request) {
if (request instanceof HttpServletRequest) {
return ((HttpServletRequest) request).getRequestURI();
} 	else {
return "Not an HttpServletRequest";
}
}
private FilterConfig filterConfig = null;
}}

Java代码

1. <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">   
2.         <property name="beanNames">   
3.             <list>   
4.                 <value>userService</value>                 
5.             </list>   
6.         </property>   
7.         <property name="interceptorNames">   
8.             <list>   
9.                 <value>jamonInterceptor</value>   
10.             </list>   
11.         </property>   
12.     </bean>   
13.        
14.     <bean id="jamonInterceptor" class="org.springframework.aop.interceptor.JamonPerformanceMonitorInterceptor">   
15. </bean>  

<bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
<property name="beanNames">
<list>
<value>userService</value>
</list>
</property>
<property name="interceptorNames">
<list>
<value>jamonInterceptor</value>
</list>
</property>
</bean>
<bean id="jamonInterceptor" class="org.springframework.aop.interceptor.JamonPerformanceMonitorInterceptor">
</bean>

Java代码

1. log4j.logger.org.springframework.aop.interceptor.JamonPerformanceMonitorInterceptor = TRACE  

log4j.logger.org.springframework.aop.interceptor.JamonPerformanceMonitorInterceptor = TRACE

Java代码

1. /**  
2.    * <p>Attempts to establish a connection with the data source that  
3.    * this <code>DataSource</code> object represents.  
4.    *  
5.    * @return  a connection to the data source  
6.    * @exception SQLException if a database access error occurs  
7.    */  
8.   Connection getConnection() throws SQLException;   
9.          
10.   /**  
11.    * <p>Attempts to establish a connection with the data source that  
12.    * this <code>DataSource</code> object represents.  
13.    *  
14.    * @param username the database user on whose behalf the connection is   
15.    *  being made  
16.    * @param password the user's password  
17.    * @return  a connection to the data source  
18.    * @exception SQLException if a database access error occurs  
19.    * @since 1.4  
20.    */  
21.   Connection getConnection(String username, String password)    
22.     throws SQLException;  

/**
* <p>Attempts to establish a connection with the data source that
* this <code>DataSource</code> object represents.
*
* @return  a connection to the data source
* @exception SQLException if a database access error occurs
*/
Connection getConnection() throws SQLException;
/**
* <p>Attempts to establish a connection with the data source that
* this <code>DataSource</code> object represents.
*
* @param username the database user on whose behalf the connection is
*  being made
* @param password the user's password
* @return  a connection to the data source
* @exception SQLException if a database access error occurs
* @since 1.4
*/
Connection getConnection(String username, String password)
throws SQLException;

Java代码

1. /**  
2.  * @author ahuaxuan(aaron zhang)  
3.  * @since 2008-2-25  
4.  * @version $Id$  
5.  */  
6. public class MonitorDataSource implements DataSource {   
7.     public DataSource realDataSource;   
8.   
9.     public void setRealDataSource(DataSource realDataSource) {   
10.         this.realDataSource = realDataSource;   
11.     }   
12.   
13.     public DataSource getRealDataSource() {   
14.         return realDataSource;   
15.     }   
16.     public Connection getConnection() throws SQLException {   
17. //表示由jamon来代理realDataSource返回的Connection   
18.         return MonProxyFactory.monitor(realDataSource.getConnection());   
19.     }   
20.   
21.     public Connection getConnection(String username, String password)   
22.             throws SQLException {   
23. //表示由jamon来代理realDataSource返回的Connection   
24.   
25.         return MonProxyFactory.monitor(realDataSource.getConnection(username,   
26.                 password));   
27.     }   
28. }  

/**
* @author ahuaxuan(aaron zhang)
* @since 2008-2-25
* @version $Id$
*/
public class MonitorDataSource implements DataSource {
public DataSource realDataSource;
public void setRealDataSource(DataSource realDataSource) {
this.realDataSource = realDataSource;
}
public DataSource getRealDataSource() {
return realDataSource;
}
public Connection getConnection() throws SQLException {
//表示由jamon来代理realDataSource返回的Connection
return MonProxyFactory.monitor(realDataSource.getConnection());
}
public Connection getConnection(String username, String password)
throws SQLException {
//表示由jamon来代理realDataSource返回的Connection
return MonProxyFactory.monitor(realDataSource.getConnection(username,
password));
}
}

Java代码

1. <bean id="writeMonitorDataSource" class="org.ahuaxuan.MonitorDataSource" destroy-method="close">   
2.         <property name="realDataSource" ref="writeDataSource"/>   
3.     </bean>  

<bean id="writeMonitorDataSource" class="org.ahuaxuan.MonitorDataSource" destroy-method="close">
<property name="realDataSource" ref="writeDataSource"/>
</bean>

Java代码

1. <bean id="writeDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">   
2.         <property name="driverClassName">   
3.             <value>${jdbc.driverClassName}</value>   
4.         </property>   
5.         <property name="url">   
6.             <value>${jdbc.url}</value>   
7.         </property>   
8.         <property name="username">   
9.             <value>${jdbc.username}</value>   
10.         </property>   
11.         <property name="password">   
12.             <value>${jdbc.password}</value>   
13.         </property>   
14.         <property name="maxActive">   
15.             <value>${jdbc.maxActive}</value>   
16.         </property>   
17.         <property name="maxIdle">   
18.             <value>${jdbc.maxIdle}</value>   
19.         </property>   
20.         <property name="maxWait">   
21.             <value>${jdbc.maxWait}</value>   
22.         </property>   
23. </bean>  

<bean id="writeDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName">
<value>${jdbc.driverClassName}</value>
</property>
<property name="url">
<value>${jdbc.url}</value>
</property>
<property name="username">
<value>${jdbc.username}</value>
</property>
<property name="password">
<value>${jdbc.password}</value>
</property>
<property name="maxActive">
<value>${jdbc.maxActive}</value>
</property>
<property name="maxIdle">
<value>${jdbc.maxIdle}</value>
</property>
<property name="maxWait">
<value>${jdbc.maxWait}</value>
</property>
</bean>

最近的一个项目在Hibernate使用C3P0的连接池，数据库为Mysql。开发测试没有问题，在运行中每个一段长的空闲时间就出现异常:

1. org.hibernate.exception.JDBCConnectionException: could not execute query
2. at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:74)
3. at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
4. .......
5. Caused by: com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException: No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error:
8. ** BEGIN NESTED EXCEPTION **
10. com.mysql.jdbc.CommunicationsException
11. MESSAGE: Communications link failure due to underlying exception:
13. ** BEGIN NESTED EXCEPTION **
15. java.net.SocketException
16. MESSAGE: Broken pipe
18. STACKTRACE:
20. java.net.SocketException: Broken pipe
21. at java.net.SocketOutputStream.socketWrite0(Native Method)
22. ......
23. ** END NESTED EXCEPTION **

查看了Mysql的文档，以及Connector/J的文档以及在线说明发现，出现这种异常的原因是：

Mysql服务器默认的“wait_timeout”是8小时，也就是说一个connection空闲超过8个小时，Mysql将自动断开该connection。这就是问题的所在，在C3P0 pools中的connections如果空闲超过8小时，Mysql将其断开，而C3P0并不知道该connection已经失效，如果这时有Client请求connection，C3P0将该失效的Connection提供给Client，将会造成上面的异常。

解决的方法有3种：

1. 增加wait_timeout的时间。
2. 减少Connection pools中connection的lifetime。
3. 测试Connection pools中connection的有效性。

当然最好的办法是同时综合使用上述3种方法，下面就DBCP和C3P0分别做一说明，假设wait_timeout为默认的8小时

DBCP增加以下配置信息:

//set to 'SELECT 1'

validationQuery = "SELECT 1"

//set to 'true'

testWhileIdle = "true"

//some positive integer

timeBetweenEvictionRunsMillis = 3600000

//set to something smaller than 'wait_timeout'

minEvictableIdleTimeMillis = 18000000

//if you don't mind a hit for every getConnection(), set to "true"

testOnBorrow = "true"

C3P0增加以下配置信息:
 

//获取connnection时测试是否有效

testConnectionOnCheckin = true

//自动测试的table名称

automaticTestTable=C3P0TestTable

//set to something much less than wait_timeout, prevents connections from going stale

idleConnectionTestPeriod = 18000

//set to something slightly less than wait_timeout, preventing 'stale' connections from being handed out

maxIdleTime = 25000

//if you can take the performance 'hit', set to "true"

testConnectionOnCheckout = true

 

 

 

在配置文件中要写成  <property name="minPoolSize"><value>1</value></property> 格式

不能写成 这样<property name="properties">
   <props>
    <prop key="c3p0.initialPoolSize">1</prop>

   </props>

</property>

c3p0不能完全识别!!

不高兴 2009-08-11 17:27 发表评论

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