JPA composite primary key usage

1、 Create a table with a composite primary key User

This table uses username+phone As a composite component

create table user
(
    username varchar(50) not null,
    phone     varchar(11) not null,
    email     varchar(20) default '',
    address   varchar(50) default '',
    primary key (username, phone)
) default charset = utf8

2、java An entity class that creates a composite primary key in

import lombok.Data;
import javax.persistence.*;
import java.io.Serializable;
 
@Data
@Entity
public class UserKey implements Serializable {
    
    private String username;
    private String phone;
}

3、 Create the entity class of the table

Use... On entity classes @IdClass Annotation specifies the composite primary key . meanwhile , Need to be in name and phone Field @Id Annotations are marked as primary keys

import lombok.Data;
import javax.persistence.*;
 
@Data
@Entity
@Table(name = "user")
@IdClass(value = UserKey.class)
public class User {
    
    @Id
    @Column(nullable = false)
    private String username;
 
    @Id
    @Column(nullable = false)
    private String phone;
 
    @Column
    private String email;
 
    @Column
    private String address;
}