Java 示例 - 使用 Applet 显示时钟？

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  问题描述

  如何使用 Applet 显示时钟？
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  解决方案

  以下示例演示如何使用 String 类的 valueOf() 方法显示时钟。& 使用 Calender 类来获取秒、分钟和小时。

  
  import java.awt.*;
  import java.applet.*;
  import java.applet.*;
  import java.awt.*;
  import java.util.*;
  public class ClockApplet extends Applet implements Runnable { 
     Thread t,t1;
     public void start() {
        t = new Thread(this);
        t.start();
     }
     public void run() { 
        t1 = Thread.currentThread();
        while(t1 == t) {
           repaint();
           try {
              t1.sleep(1000);    
           }
           catch(InterruptedException e){}
        }
     }
     public void paint(Graphics g) {
        Calendar cal = new GregorianCalendar();
        String hour = String.valueOf(cal.get(Calendar.HOUR));
        String minute = String.valueOf(cal.get(Calendar.MINUTE));
        String second = String.valueOf(cal.get(Calendar.SECOND));
        g.drawString(hour + ":" + minute + ":" + second, 20, 30);
     }
  }
  

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  结果

  上面的代码示例将在启用 java 的 Web 浏览器中产生以下结果。

  
  View in Browser. 
  

  下面是另一个使用 Applet 显示时钟的示例。

  
  import java.applet.*;  
  import java.awt.*;  
  import java.util.*;  
  import java.text.*;  
    
  public class javaApplication6 extends Applet implements Runnable {  
     Thread t1 = null;  
     int hours = 0, minutes = 0, seconds = 0;
     String time = "";
     
     public void init() {  
        setBackground( Color.green);  
     }  
     public void start() {
        t1 = new Thread( this );
        t1.start();
     } 
     public void run() {
        try {
           while (true) {
              Calendar cal = Calendar.getInstance();  
              hours = cal.get( Calendar.HOUR_OF_DAY );  
              if ( hours > 12 ) hours -= 12;  
              minutes = cal.get( Calendar.MINUTE );  
              seconds = cal.get( Calendar.SECOND );
              
              SimpleDateFormat formatter = new SimpleDateFormat("hh:mm:ss");  
              Date d = cal.getTime();  
              time = formatter.format( d );
              
              repaint();  
              t1.sleep( 1000 ); 
           }  
        }  
        catch (Exception e) { }  
     } 
     public void paint( Graphics g ) {
        g.setColor( Color.blue );  
        g.drawString( time, 50, 50 );  
     }  
  }