单独使用Struts架构的定时器的调用

基本思路如下：
1、定义一个实现了ServletContextListener的类
2、在contextInitialized（）和contextDestroyed（）调用自定义的定时程序
3、在web.xml里面配置这个 ServletContextListener

代码示例：
（程序来源 http://blog.csdn.net/zhuche110/archive/2008/05/06/2400122.aspx）

public class WorkServiceImpl implements WorkService , ServletContextListener{

    public void contextDestroyed(ServletContextEvent arg0){
       timer.cancel();
       System.out.println("定时器已销毁");
    }

    public void contextInitialized(ServletContextEvent event){
       timer = new java.util.Timer(true);
       sampleTask =  new SampleTask(event.getServletContext());
       System.out.println("定时器已启动");
       timer.schedule(sampleTask, 0, 60 * 60 * 1000);
       System.out.println("已经添加任务调度表");
    }
}


class SampleTask extends TimerTask{

    private ServletContext context;
    private static boolean isRunning = false;
    private static boolean flag = true;
    private static final int C_SCHEDULE_HOUR = 23;
    private WorkServiceImpl workService;

    public SampleTask(ServletContext context){
        this.context = context;
    }

    public void run() {
    workService = new WorkServiceImpl();
        Calendar cal = Calendar.getInstance();
        if (!isRunning){
            if (C_SCHEDULE_HOUR == cal.get(Calendar.HOUR_OF_DAY) && flag){
                isRunning = true;
                workService.autoWorkOff();
                isRunning = false;
                flag = false;
                context.log("指定任务执行结束");
            }
        } else{
            context.log("上一次任务执行还未结束");
        }
        if(C_SCHEDULE_HOUR != cal.get(Calendar.HOUR_OF_DAY)){
            flag = true;
        }
      }
}

要使用此监听器需要在web.xml中配置,如下:
<listener>
        <listener-class>com.css.wam.service.impl.WorkServiceImpl </listener-class>
</listener>