java定期执行一个方法详解编程语言

在下面的例子中,我们使用DelayedMethod扩展了线程类。这个简称类通过构造函数来指定时间间隔，间隔执行。

import java.applet.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.net.*; 
 
public class AnnoyingPopUps extends Applet implements 
    ActionListener { 
  Button b1, b2; 
  DelayedMethod dm; 
  int x = 0; 
 
  public void init() { 
     b1 = new Button("Start Annoying Popops"); 
     b2 = new Button("Stop Annoying Popops"); 
     add(b1); add(b2); 
     b1.addActionListener(this);b2.addActionListener(this); 
     dm = new DelayedMethod(this, 1000);  // 1 second 
     dm.start(); 
     } 
 
  public void actionPerformed(ActionEvent ae) { 
     if (ae.getSource() == b1) { 
        dm.oktorun = true; 
        } 
     else if(ae.getSource() == b2) { 
        dm.oktorun = false; 
       }s 
     } 
 
  public void displayPopup() { 
    SimplePopUp d = new SimplePopUp(); 
    d.show(); 
    d.setLocation(x , x); 
    x = x + 5; 
    } 
 
  class SimplePopUp extends Dialog  { 
    SimplePopUp() { 
      super(new Frame(), "annoying popup"); 
      this.addWindowListener 
       (new WindowAdapter() { 
           public void windowClosing(WindowEvent e) { 
              e.getWindow().dispose(); 
              } 
           } 
       ); 
     } 
   } 
 
  class DelayedMethod extends Thread { 
    AnnoyingPopUps myObj = null;  // customize for your need 
    boolean oktorun = false; 
    int delay; 
 
    DelayedMethod(AnnoyingPopUps myObj) { 
      this.myObj = myObj; 
      this.delay = 2000; 
      } 
 
    DelayedMethod(AnnoyingPopUps myObj, int delay) { 
      this.myObj = myObj; 
      this.delay = delay; 
      } 
 
    public void run() { 
      while (true) { 
        try { 
          sleep(delay); 
          if (oktorun)  
              myObj.displayPopup(); // customize this too! 
          }  
        catch (InterruptedException ignored) {} 
        } 
      } 
    }     
}