命令模式

public interface Command {
	public void exe();
}

public class MyCommand implements Command {

	private Receiver receiver;
	
	public MyCommand(Receiver receiver) {
		this.receiver = receiver;
	}

	@Override
	public void exe() {
		receiver.action();
	}
}

public class Receiver {
	public void action(){
		System.out.println("command received!");
	}
}

public class Invoker {
	
	private Command command;
	
	public Invoker(Command command) {
		this.command = command;
	}

	public void action(){
		command.exe();
	}
}

public class Test {

	public static void main(String[] args) {
		Receiver receiver = new Receiver();
		Command cmd = new MyCommand(receiver);
		Invoker invoker = new Invoker(cmd);
		invoker.action();
	}
}

输出：command received!

这个很哈理解，命令模式的目的就是达到命令的发出者和执行者之间解耦，实现请求和执行分开，熟悉Struts的同学应该知道，Struts其实就是一种将请求和呈现分离的技术，其中必然涉及命令模式的思想！