命令模式：就是把命令执行的类里面的功能拆分出来，变成一个个命令类，然后保存这些命令的执行顺序（用另外一个类）

感觉命令模式是一种思想：就是拆分功能，组合功能执行顺序的作用，因为顺序是保存起来的所以回溯翻查调换顺序的操作性就变强了

abstract class Command{
    protected Receiver receiver;
    
    public Command(Receiver receiver){
        this.receiver = receiver;
    }

    public abstract void Execute();
}

class ConcreteCommand extend Command{
    
    public ConcreteCommand(Receiver receiver){
        super.Command(receiver);
    }
    
    public void execute(){
        receiver.action();
    }

}

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

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

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

public class Test{
    public static void main(String[] args){
        Receiver r = new Receiver();
        Command  c = new ConcreteCommand(r);
        Invoker i = new Invoker();
        
        i.setCommand(c);
        i.executeCommand();
    }
}