普通方法引用

普通方法引用

---

public class Main {
    public static void main(String[] args) {
        //匿名內部類
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                System.out.println("hello world!");
            }
        };

        Thread thread = new Thread(runnable);
        thread.start();
    }
}

需要使用函數式接口的對象的地方可以使用lambda表達式：

public static void main(String[] args) {
    //1.
    Runnable runnable = () -> {
        System.out.println("hello world!");
    };
    
    //2.
    Thread thread = new Thread(() -> {
        System.out.println("hello world!");
    });
    thread.start();
}

有時已經有現成的方法可以完成你想要傳遞給其他代碼的某個動作，此時可以直接將該方法傳遞：

public class Main {
    public static void main(String[] args) {
        //1.
        Runnable runnable = Main::myRunnable;

        //2.
        Thread thread = new Thread(Main::myRunnable);
        thread.start();
    }

    //靜態方法
    public static void myRunnable() {
        System.out.println("hello world!");
    }
}

public class Main {
    public static void main(String[] args) {
        //創建實例
        Main main = new Main();

        //1.
        Runnable runnable = main::myRunnable;

        //2.
        Thread thread = new Thread(main::myRunnable);
        thread.start();
    }

    //非靜態方法
    public void myRunnable() {
        System.out.println("hello world!");
    }
}