Java 프레임워크에서 관찰자 패턴을 구현하는 방법은 무엇입니까?

// Observable 接口表示观察者管理功能
public interface Observable {

    void addObserver(Observer observer);

    void removeObserver(Observer observer);

    void notifyObservers();
}

// 抽象 Observer 类定义被调用的方法
public abstract class Observer {

    public abstract void update();
}

// Subject 类实现 Observable 接口
public class Subject implements Observable {

    private List<Observer> observers = new ArrayList<>();

    @Override
    public void addObserver(Observer observer) {
        observers.add(observer);
    }

    @Override
    public void removeObserver(Observer observer) {
        observers.remove(observer);
    }

    @Override
    public void notifyObservers() {
        for (Observer observer : observers) {
            observer.update();
        }
    }
}

// ConcreteObserver 类实现 Observer 接口
public class ConcreteObserver extends Observer {

    @Override
    public void update() {
        // 响应事件的逻辑
    }
}

// Main 类用于测试
public class Main {

    public static void main(String[] args) {
        Subject subject = new Subject();
        Observer observer1 = new ConcreteObserver();
        Observer observer2 = new ConcreteObserver();

        subject.addObserver(observer1);
        subject.addObserver(observer2);

        // 触发事件
        subject.notifyObservers();
    }
}