SpringBoot中Mybatis注解一对多和多对多查询实现示例

|-- user
    |-- address
    |-- carList
        |-- car1
        |-- car2

@Data
public class AddressPO {
    private Long id;
    
    private String province;
    
    private String city;
    
    private String street;
}
@Data
public class CarPO {
    private Long id;
    
    private String color;
    
    private String name;
    private Long userId;
}
@Data
public class UserPO extends AbstractPO {
    private Long id;
    private String username;
    private String passWord;
    private Integer age;
    private GenderEnum gender;
    
    private AddressPO address;
    
    private Long addressId;
    
    private List<CarPO> cars;
}

CREATE TABLE IF NOT EXISTS `user`
(
    `id`          int(11)     NOT NULL AUTO_INCREMENT COMMENT '主键',
    `username`    varchar(20) NOT NULL UNIQUE COMMENT '用户名',
    `password`    varchar(50) NOT NULL COMMENT '密码',
    `age`         int(2)      NOT NULL COMMENT '年龄',
    `gender`      varchar(10) NOT NULL COMMENT '性别',
    `address_id`  int(11)              DEFAULT NULL COMMENT '地址',
    `creater`     varchar(20)          DEFAULT NULL COMMENT '创建人',
    `modifier`    varchar(20)          DEFAULT NULL COMMENT '更新人',
    `create_time` datetime    NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
    `modify_time` datetime    NOT NUll DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '修改时间',
    PRIMARY KEY (`id`),
    KEY `index_gender` (`gender`) USING BTREE COMMENT '性别'
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8mb4
  COLLATE = utf8mb4_bin;
CREATE TABLE IF NOT EXISTS `address`
(
    `id`       int(11) NOT NULL AUTO_INCREMENT,
    `province` varchar(50) DEFAULT NULL,
    `city`     varchar(50) DEFAULT NULL,
    `street`   varchar(50) DEFAULT NULL,
    PRIMARY KEY (`id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8mb4
  COLLATE = utf8mb4_bin;
CREATE TABLE IF NOT EXISTS `car`
(
    `id`      int(11) NOT NULL AUTO_INCREMENT,
    `color`   varchar(50) DEFAULT NULL,
    `name`    varchar(50) DEFAULT NULL,
    `user_id` int(11)     DEFAULT NULL,
    PRIMARY KEY (`id`)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8mb4
  COLLATE = utf8mb4_bin;
INSERT INTO `user`(username, password, age, gender, address_id)
VALUES ('KimZing', '123456', '25', 'MAN', 1), ('kim', '123456', '25', 'MAN', 2);
INSERT INTO `address`
VALUES ('1', '北京', '北京', '王府井'),
       ('2', '天津', '天津', '周良'),
       ('3', '安徽', '宿州', '涌桥'),
       ('4', '广东', '广州', '顺德');
INSERT INTO
    `car`
VALUES
('1', 'green', '路虎', '1'),
('2', 'white', '奔驰', '2'),
('3', 'blue', '玛莎拉蒂', '1'),
('4', 'yellow', '兰博基尼', '2');

@Mapper
public interface AddressRepository {
    
    @Select("SELECT * FROM `address` WHERE id = #{id}")
    AddressPO findAddressById(Long id);
}

@Mapper
public interface MysqlUserRepository {
    @Select("SELECT * FROM `user` WHERE id = #{id}")
    UserPO find(Long id);
}

@Mapper
public interface mysqlUserRepository {
    @Select("SELECT * FROM `user` WHERE id = #{id}")
    @Results({
    @Result(property = "address", column = "address_id",
                    one = @One(select = "com.kimzing.data.repository.AddressRepository.findAddressById"))
    })
    UserPO find(Long id);
}

@Mapper
public interface CarRepository {
    
    @Select("SELECT * FROM `car` WHERE user_id = #{userId}")
    List<Car> findCarsByUserId(Long userId);
}

@Mapper
public interface MysqlUserRepository {
    @Select("SELECT * FROM `user` WHERE id = #{id}")
    UserPO find(Long id);

}

package com.kimzing.data.repository.impl;
import com.kimzing.data.domain.po.UserPO;
import org.apache.ibatis.annotations.*;
import java.util.List;

@Mapper
public interface MySqlUserRepository {
    @Select("SELECT * FROM `user` WHERE id = #{id}")
    @Results({
            @Result(property = "address", column = "address_id",
                    one = @One(select = "com.kimzing.data.repository.AddressRepository.findAddressById")),
            @Result(property = "cars", column = "id",
                    many = @Many(select = "com.kimzing.data.repository.CarRepository.findCarsByUserId"))
    }),
    // 对userId进行赋值
    @Result(property = "id", column = "id")
    UserPO find(Long id);
}