写一个类时什么时候需要重写toString

一般需要打印出来的时候需要重写toString方法

例如：User.java类

 public class User {

     private String name;

     @Value(value="北京欢迎你",xxx="666")
     private String address;

     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getAddress() {
         return address;
     }
     public void setAddress(String address) {
         this.address = address;
     }
     @Override
     public String toString() {
         return "User [name=" + name + ", address=" + address + "]";
     }

 }

User.java

Main.java

 public class Main {

     public static void main(String[] args) {
         User user = new User();
         System.out.println(user);
     }

 }

Main.java

打印出的（因为没有赋值所以为空）：