编辑“︁Java命令模式”︁（章节）

== 代码示例 ==

以下是一个简单的Java实现示例，展示如何使用命令模式控制电灯的开关：

<syntaxhighlight lang="java">
// 命令接口
interface Command {
    void execute();
}

// 接收者：电灯
class Light {
    public void turnOn() {
        System.out.println("Light is ON");
    }

    public void turnOff() {
        System.out.println("Light is OFF");
    }
}

// 具体命令：开灯
class TurnOnLightCommand implements Command {
    private Light light;

    public TurnOnLightCommand(Light light) {
        this.light = light;
    }

    @Override
    public void execute() {
        light.turnOn();
    }
}

// 具体命令：关灯
class TurnOffLightCommand implements Command {
    private Light light;

    public TurnOffLightCommand(Light light) {
        this.light = light;
    }

    @Override
    public void execute() {
        light.turnOff();
    }
}

// 调用者：遥控器
class RemoteControl {
    private Command command;

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

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

// 客户端代码
public class CommandPatternDemo {
    public static void main(String[] args) {
        Light light = new Light();
        Command turnOn = new TurnOnLightCommand(light);
        Command turnOff = new TurnOffLightCommand(light);

        RemoteControl remote = new RemoteControl();

        remote.setCommand(turnOn);
        remote.pressButton(); // 输出: Light is ON

        remote.setCommand(turnOff);
        remote.pressButton(); // 输出: Light is OFF
    }
}
</syntaxhighlight>

=== 输出 ===
<pre>
Light is ON
Light is OFF
</pre>