Reference：《Java定时器timer.schedule在Web中间隔执行任务和定时》《【Java】Timer和TimerTask详解》
做了一个Demo，完成如下的功能：
让Tomcat在WEB程序启动的时候启动一个线程池和一个Timer线程，Timer线程每隔一段时间跑一次（比如检查到期的用户，类似轮询查看），然后触发另一个后台线程（甩给线程池去处理，比如处理到期的用户，发送等）。
直接用代码说话
StarupListener.java
package Listeners;
import java.util.Timer;
import java.util.concurrent.Executors;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import BackStage.MyTimerTask;
import Support.PoolManager;
public class StartupListener implements ServletContextListener {
@Override
public void contextDestroyed(ServletContextEvent sce) {
sce.getServletContext().log("定时器销毁");
}
@Override
public void contextInitialized(ServletContextEvent sce) {
sce.getServletContext().log("启动线程池");
// Start a thread pool to deal with different task;
PoolManager.pool = Executors.newFixedThreadPool(10);
sce.getServletContext().log("启动定时器");
//Create a Daemon timer thread
Timer timer=new Timer(true);
// 每隔10秒钟执行任务
timer.schedule(new MyTimerTask(sce.getServletContext()), 0,10 * 1000);
sce.getServletContext().log("已经添加任务调度表");
}
}MyTimeTask.java
package BackStage;
import java.util.TimerTask;
import javax.servlet.ServletContext;
import Support.PoolManager;
public class MyTimerTask extends TimerTask {
private ServletContext context = null;
private int param;
public MyTimerTask(ServletContext context) {
this.context = context;
}
@Override
public void run() {
context.log("开始执行指定定時任务");
// TODO 自定义
System.err.println("号称每10秒钟跑一次哦！我要调用线程池去执行另外的任务");
//让线程池去跑一个任务
PoolManager.pool.execute(new WorkThread(param++));
context.log("指定定時任务执行结束");
}
}PoolManager.java
package Support;
import java.util.concurrent.ExecutorService;
public class PoolManager {
public static ExecutorService pool;
}WorkThread.java
package BackStage;
public class WorkThread implements Runnable {
private int param;
public WorkThread(int param) {
this.param = param;
}
@Override
public void run() {
// TODO Do something
System.err.println("我被线程池调用执行啦~！参数：" + param);
}
}web.xml片段
<listener> <listener-class>Listeners.StartupListener</listener-class> </listener>
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