【JAVA】JAVA回调，

【JAVA】JAVA回调，

一般我们A调用B，可以有三种方式
1.同步
2.异步
3.回调
我们这里讲讲回调

假设我们这里老师和学生，老师需要等学生回答完问题，那么就可以这样子：

老师实现接口:

public interface Callback {

    void callBack(int answer);

}

老师：

public class Teacher implements Callback {

    private Student student;

    public Teacher(Student student) {
        this.student = student;
    }

    public void ask(){
        student.answer(this);
    }

    @Override
    public void callBack(int answer) {
        System.out.println("over" + answer);
    }
}

学生实现接口

public interface Student {

    void answer(Callback callback);
    
}

学生

public class Bincai implements Student{

    @Override
    public void answer(Callback callback) {
        callback.callBack(3);
    }
}

测试类

public class Test {
    public static void main(String[] args) {
      Student student = new Bincai();
      Teacher teacher = new Teacher(student);

      teacher.ask();
    }
}