命令模式

最新推荐文章于 2025-08-21 11:44:50 发布

rock93

最新推荐文章于 2025-08-21 11:44:50 发布

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CC 4.0 BY-SA版权

分类专栏：设计模式文章标签：命令模式

本文链接：https://blog.youkuaiyun.com/rock93/article/details/74013477

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本文介绍了一种常用的设计模式——命令模式，并通过具体的代码实现展示了如何使用该模式来控制不同的设备，如灯光和风扇的开关操作及其撤销功能。文章通过创建抽象命令接口及其实现类，实现了设备状态的灵活切换。

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

}public class LightOffCommand implements Command{
	Light light;
	public LightOffCommand(Light light) {
		super();
		this.light = light;
	}
	@Override
	public void execute() {
		light.off();
	}
	@Override
	public void undo() {
		light.on();
	}
}
public class FanOnCommand implements Command{
	Fan fan;
	public FanOnCommand(Fan fan) {
		super();
		this.fan = fan;
	}
	@Override
	public void execute() {
		fan.on();
	}

	@Override
	public void undo() {
		fan.off();
	}

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

public class Control {
	Command onCommand;
	Command offCommand;
	Command command;
	public void setCommand(Command oncom,Command offcom){
		onCommand = oncom;
		offCommand = offcom;
	}
	public void on(){
		command = onCommand;
		onCommand.execute();
	}
	public void off(){
		command = offCommand;
		offCommand.execute();
	}
	public void undo(){
		command.undo();
	}
}

public class TestCommand {
	public static void main(String[] args) {
		Light light = new Light();
		Fan fan = new Fan();
		LightOffCommand lightOff = new LightOffCommand(light);
		LightOnCommand lightOn = new LightOnCommand(light);
		Control con = new Control();
		con.setCommand(lightOn, lightOff);
		con.on();
		con.undo();
		con.off();
		
		FanOffCommand fanOffCommand = new FanOffCommand(fan);
		FanOnCommand fanOnCommand = new FanOnCommand(fan);
		con.setCommand(fanOnCommand, fanOffCommand);
		con.on();
		con.undo();
		con.off();
	}
}