该代码实现了在系统右下角的任务栏中显示程序的图标,并且最小化程序后单击图标可以显示出来这个程序窗口

 

import java.awt.Color; 
  import java.awt.Image;
  import java.awt.MenuItem;
  import java.awt.PopupMenu;
  import java.awt.Toolkit;
  
  
  import javax.swing.JFrame;
  import javax.swing.JLabel;
  
  
  public class test extends JFrame
  {
  long setTime = 30*1000;
  
  JLabel jl = new JLabel("剩余时间:");
  
  JLabel jl1 = new JLabel();
  
  PopupMenu popupMenu1 = new PopupMenu();
  MenuItem menuItem1 = new MenuItem();
  
  public examTime(){
   this.setLocation(200, 200);
   this.setSize(300, 200);
   isTray();
   this.setVisible(true);
   addWindowListener(new WindowAdapter()
   {
   public void windowIconified(WindowEvent evt)
   {
   unVisible();
   }
   });
  
   popupMenu1.setLabel("PopupMenu");
   menuItem1.setLabel("打开");
   menuItem1.addActionListener(new ActionListener()
   {
   public void actionPerformed(ActionEvent evt)
   {
   showw();
   }
   });
   popupMenu1.add(menuItem1);
  }
  
  public void unVisible(){
   this.setVisible(false);
  }
  
  public void showw(){
   this.setVisible(true);
  }
  public void isTray()
   {
   try
   {
   if (SystemTray.isSupported())
   {// 判断当前平台是否支持系统托盘
   SystemTray st = SystemTray.getSystemTray();
   Image image = Toolkit.getDefaultToolkit().getImage(
   "E:/eclipse/workspace/test/test.gif");//定义托盘图标的图片
   TrayIcon ti = new TrayIcon( image);
   ti.setToolTip ( "test ");
   ti.setPopupMenu ( this.popupMenu1);
   st.add(ti);
   }
   }
   catch (Exception e)
   {
  
   }
  
  
   }
  public static void main(String[] args)
   {
   new test();
   }
  }