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 + "]";
    }
    
    
}

Main.java

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

}

 

 打印出的（因为没有赋值所以为空）：