2019-02-12——方法调用

软件模块之间总是存在着一定的接口，从调用方式上，可以把他们分为三类：同步调用、回调和异步调用。

• 同步调用：即单向调用，阻塞。A调用B，需要拿到B的结果后才能继续执行，是顺序调用

public class A {

    private B b;

    public A(B b){
        this.b = b;
    }
    public void ma(){
        b.mb();
        System.out.println("this is A.ma()");
    }
}




public class B {
    public void mb(){
        System.out.println("this is B.mb()");
    }
}

• 异步调用：非阻塞调用。A调用B，不需要拿到B的结果就能继续执行。异步调用通常采用多线程的方法来达到目的。

public class A {

    private B b;

    public A(B b){
        this.b = b;
    }
    public void ma(){
        new Thread(() -> b.mb()).start();
        System.out.println("this is A.ma()");
    }
}




public class B {
    public void mb(){
        System.out.println("this is B.mb()");
    }
}

• 回调：双向调用。A调用B的方法，同时在B的方法中调用了A的另一个方法

public class A {

    private B b;

    public A(B b){
        this.b = b;
    }
    public void ma(){
        b.mb(this);
        System.out.println("this is A.ma()");
    }

    public void callback(){
        System.out.println("this is A.callback()");
    }
}




public class B {
    public void mb(A a){
        a.callback();
        System.out.println("this is B.mb()");
    }
}

• 异步回调：在回调的基础上异步处理

public class A {

    private B b;

    public A(B b){
        this.b = b;
    }
    public void ma(){
        new Thread(()->b.mb(this)).start();
        System.out.println("this is A.ma()");
    }

    public void callback(){
        System.out.println("this is A.callback()");
    }
}




public class B {
    public void mb(A a){
        System.out.println("this is B.mb()");
        a.callback();
    }
}

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• https://blog.csdn.net/zhenwei1994/article/details/79615861
• https://www.cnblogs.com/puyangsky/p/5581051.html
• https://www.cnblogs.com/imzhudi/p/7161770.html