(小白问题) Java 关于 this 的指向问题 - V2EX
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rabbbit

(小白问题) Java 关于 this 的指向问题

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  •   rabbbit Oct 12, 2020 1997 views
    This topic created in 2026 days ago, the information mentioned may be changed or developed.

    这个 this 到底指向谁, 为什么 s.getName() 输出 foo, 而 s.name 输出 bar.
    我以为两个都结果都应该是 bar,是哪里搞错了?

    class Person { public String name = "foo"; public String getName() { return this.name; } } class Student extends Person { public String name = "bar"; } public class Hello { public static void main(String[] args) { Student s = new Student(); System.out.println(s.getName()); // foo System.out.println(s.name); // bar } } 
    4 replies    2020-10-13 14:02:03 +08:00
    yumenawei
        1
    yumenawei  
       Oct 12, 2020   1
    帮顶~
    billlee
        2
    billlee  
       Oct 12, 2020   1
    字段没有多态性,this.name 取的是编译期 this 变量所属类的 name, 对于 Person::getName 来说,this 是 Person, this.name 是 "foo".
    对于 main 中的 s.name 来说,s 是 Student, s.name 是 "bar".
    itechify
        3
    itechify  
    PRO
       Oct 12, 2020 via Android   1
    多态针对接口(行为,方法),属性没有多态
    dushe
        4
    dushe  
       Oct 13, 2020
    this 指向最近的对象
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