异常：“严重: The web application [] appears to have started a thread named [Thread-”



严重: The web application [] appears to have started a thread named [TestScheduler_Worker-1] but has failed to stop it. This is very likely to create a memory leak.

1,获取dump

2,从dump找到正在运行的线程所属class

3,在myeclise 开启debug模式,给正在运行的方法加上断点

4,这时你会发现当停止application时,有一个线程还没有停止掉

5,在 AppContextListener 进行contextDestroyed时,要加一段额外的代码,用来我们关闭tomcat的时候可以同时关闭此线程

例如此例:

在tomcat7+quartz1.8/1.7 + spring3.0.5做定时任务的时候 ， 当关闭tomcat时抛异常"严重: The web application [] appears to have started a thread named [Thread-"：

ar 27, 2013 6:05:35 PM org.apache.coyote.AbstractProtocol pause
INFO: Pausing ProtocolHandler ["http-nio-8082"]
Mar 27, 2013 6:05:35 PM org.apache.catalina.core.StandardService stopInternal
INFO: Stopping service Catalina
Mar 27, 2013 6:05:35 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/****] appears to have started a thread named [startQuertz_Worker-1] buthas       failed to stop it. This is very likely to create a memory leak.
Mar 27, 2013 6:05:35 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/****] appears to have started a thread named [startQuertz_Worker-2] buthas  failed to stop it. This is very likely to create a memory leak.
Mar 27, 2013 6:05:35 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/****] appears to have started a thread named [startQuertz_Worker-3] buthas   failed to stop it. This is very likely to create a memory leak.
Mar 27, 2013 6:05:35 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads

原因:tomcat在shutdown做清理工作的时候没能等待quartz完成cleanShutdown。就是tomcat太心急了，说 “quartz  , 我关门了，你走吧！”，还没等quartz反应过来，就要关大门，这时发现 “quartz , 你怎么还在这儿呀！”。

解决办法：自己实现一个ServletContextListener，在contextDestroyed的时候主动调用quartz schedular的shutdown方法,并且主线程sleep一会儿.

代码:
public class QuartzContextListener implements ServletContextListener {

    /*
     * 测试代码写得随便
     *
     * @seejavax.servlet.ServletContextListener#contextDestroyed(javax.servlet.
     * ServletContextEvent)
     */
    @Override
    public void contextDestroyed(ServletContextEvent arg0) {
        WebApplicationContext webApplicationContext = (WebApplicationContext) arg0
                .getServletContext()
                .getAttribute(
                        WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
        org.quartz.impl.StdScheduler startQuertz = (org.quartz.impl.StdScheduler) webApplicationContext
                .getBean("startQuertz");
        if(startQuertz != null) {
            startQuertz.shutdown();
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    /*
     * (non-Javadoc)
     *
     * @see
     * javax.servlet.ServletContextListener#contextInitialized(javax.servlet
     * .ServletContextEvent)
     */
    @Override
    public void contextInitialized(ServletContextEvent arg0) {
< span style="white-space:pre">        //不做任何事情
    }

}

最后在 web.xml 配置QuartzContextListener。

注意:如果tomcat在Dameon模式下,以上方法不起作用,请参考:
http://wiki.apache.org/tomcat/MemoryLeakProtection