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一、概述

       命令模式（Command），将一个请求封装为一个对象，从而使你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤销的操作。

二、UML图示

三、代码实现

1、reciever类

public class Barbecuer {    public void bakeMutton(){        System.out.println("烤羊肉串！");    }    public void bakeChilkenWing(){        System.out.println("烤鸡翅！");    }}

2、command类

public abstract class Command {    protected Barbecuer receiver;    public Command(Barbecuer receiver) {        this.receiver = receiver;    }    public abstract void excuteCommand();}

3、具体命令类

public class BakeChickenWingCommand extends Command {    public BakeChickenWingCommand(Barbecuer receiver) {        super(receiver);    }    @Override    public void excuteCommand() {        receiver.bakeChilkenWing();    }}public class BakeMuttonCommand extends Command {    public BakeMuttonCommand(Barbecuer receiver) {        super(receiver);    }    @Override    public void excuteCommand() {        receiver.bakeMutton();    }}

4、invoker类

public class Waiter {    private List list = new ArrayList<>();    public void setOrder(Command command){        list.add(command);        System.out.println("增加新订单："+command.getClass().getName());    }    public void cancelOrder(Command command){        list.remove(command);        System.out.println("取消订单："+command.getClass().getName());    }    public void notifyMessage(){        for (Command comand:list) {            comand.excuteCommand();        }    }}

5、测试类

public class Test {    public static void main(String[] args) {        //开店前准备        Barbecuer boy =new Barbecuer();        BakeChickenWingCommand bakeChickenWingCommand = new BakeChickenWingCommand(boy);        BakeChickenWingCommand bakeChickenWingCommand1 = new BakeChickenWingCommand(boy);        BakeMuttonCommand bakeMuttonCommand = new BakeMuttonCommand(boy);        Waiter girl = new Waiter();        //顾客点菜        girl.setOrder(bakeChickenWingCommand);        girl.setOrder(bakeChickenWingCommand1);        girl.setOrder(bakeMuttonCommand);        //通知厨房        girl.notifyMessage();    }}输出：增加新订单：com.zbf.commandMode.BakeChickenWingCommand增加新订单：com.zbf.commandMode.BakeChickenWingCommand增加新订单：com.zbf.commandMode.BakeMuttonCommand烤鸡翅！烤鸡翅！烤羊肉串！

注：参考文献《大话设计模式》程杰著。