测试匿名内部类和lambda表达式的this“指针”

/**
 * 测试匿名内部类和lambda表达式的this“指针”
 * 结论:
 * lambda表达式虽然也会构建一个类,但是内部却没有自己的this指针,
 * 当在内部使用this指针时,代指的是表达式外部对应的对象
 */
public class Test {
    public static void main(String[] args) {
        new Test().test1();
    }

    void test1(){
        System.out.println("Test对象hashCode=" + this.hashCode());
        System.out.println("------------------------------");
        f(()->{
            System.out.println("lambda内的this:" + this.hashCode());
        });
        System.out.println("--------------");
        f(new Inter1() {
            @Override
            public void func() {
                System.out.println("内部类内的this:" + this.hashCode());
            }
        });
    }

    private static void f(Inter1 i) {
        i.func();
        System.out.println("i.hashCode=" + i.hashCode());
        System.out.println("i所属class=" + i.getClass());
    }

}

interface Inter1{
    void func();
}

 补充:

在Java官方文档里有这样一句话:

Lambda expressions are lexically scoped. This means that they do not inherit any names from a supertype or introduce a new level of scoping. Declarations in a lambda expression are interpreted just as they are in the enclosing environment. 

就是说lambda表达式为词法作用域,即它不会从父类继承任何名字,也不会引入新的作用域

posted @ 2020-07-24 23:38  名字下次再取  阅读(373)  评论(0)    收藏  举报