这个是java设计模式的文件 可能对了解设计思想有一定帮助

				import java.awt.*;
				import java.awt.event.*;
				
				public class testCommand extends Frame
				   implements ActionListener
				{
				   Menu mnuFile;
				   fileOpenCommand mnuOpen;
				   fileExitCommand mnuExit;
				   btnRedCommand btnRed;
				   Panel p;
				   Frame fr;
				   //-----------------------------------------
				   public testCommand()
				   {
				      super("Frame without commands");
				      fr = this;     //save frame object
				      MenuBar mbar = new MenuBar();
				      setMenuBar(mbar);
				
				      mnuFile = new Menu("File", true);
				      mbar.add(mnuFile);
				
				      mnuOpen = new fileOpenCommand("Open...");
				      mnuFile.add(mnuOpen);
				      mnuExit = new fileExitCommand("Exit");
				      mnuFile.add(mnuExit);
				
				      mnuOpen.addActionListener(this);
				      mnuExit.addActionListener(this);
				      
				      btnRed = new btnRedCommand("Red");
				      p = new Panel();
				      add(p);
				      p.add(btnRed);
				
				      btnRed.addActionListener(this);
				      setBounds(100,100,200,100);
				      setVisible(true);
				   }
				   //-----------------------------------------
				   public void actionPerformed(ActionEvent e)
				   {
				      Command obj = (Command)e.getSource();
				      obj.Execute();
				   }
				   //-----------------------------------------
				   static public void main(String argv[])
				   {
				      new testCommand();
				   }
				   //====----====-----inner class----=====----
				   class btnRedCommand extends Button implements Command
				   {
				      public btnRedCommand(String caption)
				      {
				         super(caption);
				      }
				      public void Execute()
				      {
				         p.setBackground(Color.red);
				      }
				   }
				   //------------------------------------------
				   class fileOpenCommand extends MenuItem implements Command
				   {
				      public fileOpenCommand(String caption)
				      {
				         super(caption);
				      }
				      public void Execute()
				      {
				         FileDialog fDlg=new FileDialog(fr,"Open file");
				         fDlg.show();
				      }
				   }
				   //-------------------------------------------
				   class fileExitCommand extends MenuItem implements Command
				   {
				      public fileExitCommand(String caption)
				      {
				         super(caption);
				      }
				      public void Execute()
				      {
				         System.exit(0);
				      }
				   }
				}
				//==========================================