WEB 计划任务_Oracle教程

　　在tomcat中可以注册ServletContextListener，

public void contextInitialized(ServletContextEvent sce)；
public void contextDestroyed(ServletContextEvent sce)；

答应程序在系统启动和关闭的时候作一些工作。我把线程的启动和关闭都放在这里了，这样系统在reload的时候，也会调用ServletContextListener的方法。
package market;

/**
* 侦听器程序测试
*/
public class marketListener implements Javax.servlet.ServletContextListener {
    private java.util.Timer timer;

    public marketListener() {
        System.out.println( "startup init" );
        timer = new java.util.Timer( true );
    }

    public void contextDestroyed( javax.servlet.ServletContextEvent event ) {
        System.out.println( "destory" );
        timer.cancel();
    }

    public void contextInitialized( javax.servlet.ServletContextEvent event ) {
        System.out.println( "start" );
        System.out.println( event.getServletContext().getRealPath( "/" ) );
        timer.schedule( new java.util.TimerTask() {
            public void run() {
                System.out.println( "TimerTask run..." );
            }
        } , 0 , 1000 );
    }

}
对web.XML的配置
<listener>
    <listener-class>market.marketListener</listener-class>
</listener>