Command命令模式

Java代码

   1. public class Invoker {  
   2.     private Command command;  
   3.   
   4.     public void setOrder(Command command) {  
   5.         this.command = command;  
   6.     }  
   7.     public void ExecuteCommand() {  
   8.         command.ExecuteCommand();  
   9.     }  
  10.   
  11. }  

Command类，将一个请求封装成一个对象，将一个请求具体化，方便对请求记录。
Java代码

   1. public abstract class Command {  
   2.     protected Receiver receiver;  
   3.       
   4.     public Command(Receiver receiver){  
   5.         this.receiver = receiver;  
   6.     }  
   7.       
   8.     public abstract void ExecuteCommand();  
   9. }  

ConcreteCommand类，可以将Receiver对象放到这个类里面，这个类具体实现了要怎么处理这个用户的请求。
Java代码

   1. public class ConcreteCommand extends Command {  
   2.       
   3.     public ConcreteCommand(Receiver receiver){  
   4.         super(receiver);  
   5.     }  
   6.   
   7.     @Override  
   8.     public void ExecuteCommand() {  
   9.         receiver.Execute();  
  10.     }  
  11.   
  12. }  

Receiver类，其实这个类可以没有，不过为了让设计看起来更整洁清楚。
Java代码

   1. public class Receiver {  
   2.     public void Execute(){  
   3.         System.out.println("Receiver excute!");  
   4.     }  
   5. }  

最后一个Client类。
Java代码

   1. public class Client {  
   2.     public static void main(String[] args) {  
   3.         Receiver r = new Receiver();  
   4.         Command c = new ConcreteCommand(r);   
   5.         Invoker i = new Invoker();  
   6.   
   7.         i.setOrder(c);  
   8.         i.ExecuteCommand();  
   9.     }  
  10. }