设计模式之Command模式（笔记）

命令模式：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。

首先定义一个Receiver类，用来执行请求

public class Receiver {

    public void action(){
        System.out.println("执行请求");
    }
}

接着定义Command抽象类，用来声明执行操作的接口

public abstract class Commands {

    protected Receiver receiver;

    public Commands(Receiver receiver){
        this.receiver=receiver;
    }

    public abstract void execute();
}

接着定义ConcreteCommand继承Command类

public class ConcreteCommand extends Commands{

    public ConcreteCommand(Receiver receiver) {
        super(receiver);

    }

    @Override
    public void execute() {
        receiver.action();

    }
}

然后定义Invoker类，要求该命令执行这个请求

public class Invoker {

    private Commands command;

    public void setCommand(Commands command){
        this.command=command;
    }

    public void executeCommand(){
        command.execute();
    }
}

客户端代码

public static void main(String[] args) {
    //命令模式
        Receiver receiver=new Receiver();
        Commands commands=new ConcreteCommand(receiver);
        Invoker invoker=new Invoker();
        invoker.setCommand(commands);
        invoker.executeCommand();
   }