Java定时任务

通过监听器（Listener）和定时器（Timer）定时执行某个任务

import java.util.Timer;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
 
public class MyListener implements ServletContextListener {
 
  private Timer timer = null;
 
  public void contextInitialized(ServletContextEvent event) {
    timer = new Timer(true);
    //设置任务计划，启动和间隔时间
    timer.schedule(new MyTask(), 0, 86400000);
  }
 
  public void contextDestroyed(ServletContextEvent event) {
    timer.cancel();
  }
 
}
 
 
MyTask：
 
import java.util.TimerTask;
 
public class MyTask extends TimerTask {
 
  public void run() {
    // System.out.println("call at " + (new Date()));
    // TODO 此处添加具体任务代码
  }
 
}
 

web.xml配置：

<listener>
  <listener-class>com.fastunit.samples.listener.MyListener</listener-class>
</listener>


Tiger中的新类ScheduledExecutorService功能执行周期定时任务

  import java.io.IOException;
  import java.io.PrintStream;
  import java.util.Date;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledFuture;
  import static java.util.concurrent.TimeUnit.*;

  public class ScheduleTester {
    public static void main(String[] args) {
      // Get the scheduler
      ScheduledExecutorService scheduler =
        Executors.newSingleThreadScheduledExecutor( );
      // Get a handle, starting now, with a 10 second delay

      final ScheduledFuture<?> timeHandle =

      scheduler.scheduleAtFixedRate(new TimePrinter(System.out), 0, 0, SECONDS);


      // Schedule the event, and run for 1 hour (60 * 60 seconds)

      scheduler.schedule(new Runnable( ) {
        public void run( ) {
          timeHandle.cancel(false);
        }
      }, 60*60, SECONDS);    

      }
    }

  }

  class TimePrinter implements Runnable {

    private PrintStream out;

    public TimePrinter(PrintStream out) {
      this.out = out;
    }

    public void run( ) {
      out.printf("Current time: %tr%n", new Date( ));

    }
  }