写一个类时什么时候需要重写toString

Posted 2020-10-11

 

一般需要打印出来的时候需要重写toString方法

例如：User.java类

 1 public class User {
 2     
 3     private String name;
 4 
 5     @Value(value="北京欢迎你",xxx="666")
 6     private String address;
 7     
 8     public String getName() {
 9         return name;
10     }
11     public void setName(String name) {
12         this.name = name;
13     }
14     public String getAddress() {
15         return address;
16     }
17     public void setAddress(String address) {
18         this.address = address;
19     }
20     @Override
21     public String toString() {
22         return "User [name=" + name + ", address=" + address + "]";
23     }
24     
25     
26 }

User.java

 

Main.java

1 public class Main {
2     
3     public static void main(String[] args) {
4         User user = new User();
5         System.out.println(user);
6     }
7 
8 }

Main.java

 

 

 打印出的（因为没有赋值所以为空）：