命令模式的研究以及案例举例，本次研究我的案例是遥控器控制电灯，风扇，电视等功能的实现

好的，下面我来为您介绍命令模式的研究以及案例，并且使用您提供的遥控器控制电灯、风扇、电视等功能的实现作为示例。

命令模式的研究：
命令模式是一种常用的设计模式，它可以将请求者和执行者分离开来，让请求者不必知道执行者的具体实现，从而达到松耦合的效果。在实际应用中，命令模式经常用来实现撤销、重做、批处理等功能，同时还可用来实现日志记录、事务处理等功能。

命令模式的案例：
在本案例中，我们使用命令模式来实现遥控器控制电灯、风扇、电视等功能。具体实现过程如下：

1. 定义命令接口(Command)，其中包含执行命令的方法execute()和撤销命令的方法undo()。

public interface Command {
    void execute();
    void undo();
}

2. 定义具体命令类(LightOnCommand、LightOffCommand、FanOnCommand、FanOffCommand、TVOnCommand、TVOffCommand)，它们实现了命令接口，并且包含了接收者的实例。

public class LightOnCommand implements Command {
    private Light light;
    public LightOnCommand(Light light) {
        this.light = light;
    }
    public void execute() {
        light.on();
    }
    public void undo() {
        light.off();
    }
}

public class LightOffCommand implements Command {
    private Light light;
    public LightOffCommand(Light light) {
        this.light = light;
    }
    public void execute() {
        light.off();
    }
    public void undo() {
        light.on();
    }
}

public class FanOnCommand implements Command {
    private Fan fan;
    public FanOnCommand(Fan fan) {
        this.fan = fan;
    }
    public void execute() {
        fan.on();
    }
    public void undo() {
        fan.off();
    }
}

public class FanOffCommand implements Command {
    private Fan fan;
    public FanOffCommand(Fan fan) {
        this.fan = fan;
    }
    public void execute() {
        fan.off();
    }
    public void undo() {
        fan.on();
    }
}

public class TVOnCommand implements Command {
    private TV tv;
    public TVOnCommand(TV tv) {
        this.tv = tv;
    }
    public void execute() {
        tv.on();
    }
    public void undo() {
        tv.off();
    }
}

public class TVOffCommand implements Command {
    private TV tv;
    public TVOffCommand(TV tv) {
        this.tv = tv;
    }
    public void execute() {
        tv.off();
    }
    public void undo() {
        tv.on();
    }
}

3. 定义遥控器类(RemoteControl)，它包含了多个命令按钮，并且可以设置每个按钮对应的命令。

public class RemoteControl {
    private Command[] onCommands;
    private Command[] offCommands;
    private Command undoCommand;
    public RemoteControl() {
        onCommands = new Command[3];
        offCommands = new Command[3];
        Command noCommand = new NoCommand();
        for (int i = 0; i < 3; i++) {
            onCommands[i] = noCommand;
            offCommands[i] = noCommand;
        }
        undoCommand = noCommand;
    }
    public void setCommand(int slot, Command onCommand, Command offCommand) {
        onCommands[slot] = onCommand;
        offCommands[slot] = offCommand;
    }
    public void onButtonWasPushed(int slot) {
        onCommands[slot].execute();
        undoCommand = onCommands[slot];
    }
    public void offButtonWasPushed(int slot) {
        offCommands[slot].execute();
        undoCommand = offCommands[slot];
    }
    public void undoButtonWasPushed() {
        undoCommand.undo();
    }
}

4. 定义接收者类(Light、Fan、TV)，它们实现了具体的功能。

public class Light {
    public void on() {
        System.out.println("Light is on");
    }
    public void off() {
        System.out.println("Light is off");
    }
}

public class Fan {
    public void on() {
        System.out.println("Fan is on");
    }
    public void off() {
        System.out.println("Fan is off");
    }
}

public class TV {
    public void on() {
        System.out.println("TV is on");
    }
    public void off() {
        System.out.println("TV is off");
    }
}

5. 最后，我们可以使用遥控器来控制电灯、风扇、电视等功能。

public class Client {
    public static void main(String[] args) {
        RemoteControl remote = new RemoteControl();
        Light light = new Light();
        Fan fan = new Fan();
        TV tv = new TV();
        Command lightOn = new LightOnCommand(light);
        Command lightOff = new LightOffCommand(light);
        Command fanOn = new FanOnCommand(fan);
        Command fanOff = new FanOffCommand(fan);
        Command tvOn = new TVOnCommand(tv);
        Command tvOff = new TVOffCommand(tv);
        remote.setCommand(0, lightOn, lightOff);
        remote.setCommand(1, fanOn, fanOff);
        remote.setCommand(2, tvOn, tvOff);
        remote.onButtonWasPushed(0); // 打开电灯
        remote.offButtonWasPushed(0); // 关闭电灯
        remote.undoButtonWasPushed(); // 撤销上一步操作
        remote.onButtonWasPushed(1); // 打开风扇
        remote.offButtonWasPushed(1); // 关闭风扇
        remote.onButtonWasPushed(2); // 打开电视
        remote.offButtonWasPushed(2); // 关闭电视
    }
}

通过上述示例，我们可以看到命令模式的具体实现过程，并且通过遥控器控制电灯、风扇、电视等功能，实现了命令的发出者和执行者分离的效果。