SpringBoot整合Mybatis
四、多对多实现
目标:根据id查询用户选择的运营商
1. 构建项目
使用上一章内容
2. 创建数据库
1). user表:
CREATE TABLE user(
id INT(10) NOT NULL AUTO_INCREMENT COMMENT '编号',
name VARCHAR(50) NOT NULL COMMENT '用户名',
PRIMARY KEY(id)
)ENGINE=INNODB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;
2). combo表:
CREATE TABLE combo(
id INT(10) NOT NULL AUTO_INCREMENT COMMENT '编号',
name VARCHAR(50) NOT NULL COMMENT '运营商名称',
PRIMARY KEY(id)
)ENGINE=INNODB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;
3). user_combo表:
CREATE TABLE user_combo(
uid INT(10) NULL COMMENT '用户编号',
cid INT(10) NULL COMMENT '运营商编号',
price INT(10) NULL COMMENT '价格'
)ENGINE=INNODB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;
3. 编写代码
1). 实体类Combo
位于entity包
/**
* @author Ray
* @date 2018/7/7 0007
* 运营商实体类
*/
public class Combo {
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Combo{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
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2). 实体类UserCombo
位于entity包
/**
* @author Ray
* @date 2018/7/7 0007
* 用户拥有运营商实体
*/
public class UserCombo {
private int uid;
private int cid;
private int price;
private List<Combo> combos;
public List<Combo> getCombos() {
return combos;
}
public void setCombos(List<Combo> combos) {
this.combos = combos;
}
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
public int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
@Override
public String toString() {
return "UserCombo{" +
"uid=" + uid +
", cid=" + cid +
", price=" + price +
", combos=" + combos +
'}';
}
}
3). 实体类User
位于entity包,添加UserCombo集合,添加对应的setter、getter
/**
* @author Ray
* @date 2018/7/7 0007
* 用户实体类
*/
public class User {
/**
* 编号(主键)
*/
private int id;
/**
* 用户名
*/
private String name;
/**
* 新增Phone集合
*/
private List<Phone> phones;
/**
* 新增UserCombo集合
*/
private List<UserCombo> userCombos;
public List<UserCombo> getUserCombos() {
return userCombos;
}
public void setUserCombos(List<UserCombo> userCombos) {
this.userCombos = userCombos;
}
public List<Phone> getPhones() {
return phones;
}
public void setPhones(List<Phone> phones) {
this.phones = phones;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public User() {
}
public User(String name) {
this.name = name;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
4). 数据操作类UserMapper
位于mapper包,添加查询方法selectComboById(Integer id)
/**
* @author Ray
* @date 2018/7/7 0007
* 数据操作层
*/
public interface UserMapper {
/**
* 根据id获取用户信息
*/
public User selectById(Integer id);
/**
* 查询所有用户信息
*/
public List<User> list();
/**
* 新增用户信息
*/
public int insert(User user);
/**
* 修改用户信息
*/
public int update(User user);
/**
* 删除用户信息
*/
public int delete(Integer id);
/**
* 根据id查询用户的所有电话信息
*/
public User selectPhoneById(Integer id);
/**
* 根据id查询用户选择的运营商
*/
public User selectComboById(Integer id);
}
5). UserMapper类映射UserMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.ray.mybatis.mapper.UserMapper">
<!-- 新增用户信息 -->
<insert id="insert" parameterType="user">
INSERT INTO
user(name)
VALUES
(#{name})
</insert>
<!-- 修改用户信息 -->
<update id="update" parameterType="user">
UPDATE
user
SET
name=#{name}
WHERE
id=#{id}
</update>
<!-- 删除用户信息 -->
<delete id="delete">
DELETE
FROM
user
WHERE
id=#{id}
</delete>
<!-- 根据id获取用户信息 -->
<select id="selectById" resultType="user" parameterType="int">
SELECT
*
FROM
user
WHERE
id=#{id}
</select>
<!-- 查询所有用户信息 -->
<select id="list" resultType="user">
SELECT
*
FROM
user
</select>
<!-- 注意:当多个表的字段名一样的时候,查询需要用别名,否则查询结果不理想 -->
<resultMap id="phoneMap" type="user">
<id property="id" column="id"/>
<result property="name" column="name"/>
<!-- 一对多 【ofType是映射到list集合属性中pojo的类型】 -->
<collection property="phones" ofType="phone">
<id property="id" column="pid"/>
<result property="name" column="pname"/>
<result property="number" column="number"/>
<result property="uid" column="uid"/>
</collection>
</resultMap>
<!-- 根据id查询用户的所有电话信息 -->
<select id="selectPhoneById" resultMap="phoneMap" parameterType="int">
SELECT
u.*,
p.id pid,p.name pname,p.number,p.uid
FROM
user u, phone p
WHERE
u.id=p.uid
and
u.id=#{id}
</select>
<!-- 注意:抽离userMap -->
<resultMap id="userMap" type="user">
<id property="id" column="id"/>
<result property="name" column="name"/>
</resultMap>
<!-- 注意:继承userMap -->
<resultMap id="comboMap" type="user" extends="userMap">
<!-- 一对多 -->
<collection property="userCombos" ofType="userCombo">
<result property="price" column="price"/>
<result property="uid" column="uid"/>
<result property="cid" column="cid"/>
<!-- 一对多 -->
<collection property="combos" ofType="combo">
<id property="id" column="cid"/>
<result property="name" column="cname"/>
</collection>
</collection>
</resultMap>
<!-- 根据id查询用户选择的运营商 -->
<select id="selectComboById" parameterType="int" resultMap="comboMap">
SELECT
u.*,
b.price,b.uid,b.cid,
c.id cid,c.name cname
FROM
user u,user_combo b,combo c
WHERE
u.id=b.uid
AND
b.cid=c.id
AND
u.id=#{id}
</select>
</mapper>
6). 数据控制类UserController
位于controller包
/**
* @author Ray
* @date 2018/7/7 0007
* 数据控制层
*/
@RestController
public class UserController {
@Autowired
private UserMapper userMapper;
/**
* 根据id获取用户信息
* localhost:8080/user/2
*/
@GetMapping("/user/{id}")
public User selectById(@PathVariable("id")Integer id){
User user = userMapper.selectById(id);
return user;
}
/**
* 查询所有用户信息
* localhost:8080/users
*/
@GetMapping("/users")
public List<User> list(){
List<User> users = userMapper.list();
return users;
}
/**
* 新增用户信息
* localhost:8080/user?name=Ray1
*/
@PostMapping("/user")
public String insert(User user){
int result = userMapper.insert(user);
if(result == 1){
return "success";
}
return "fail";
}
/**
* 修改用户信息
* localhost:8080/user/2?name=Ray22
*/
@PutMapping("/user/{id}")
public String update(User user, @PathVariable("id") Integer id){
int result = userMapper.update(user);
if(result == 1){
return "success";
}
return "fail";
}
/**
* 删除用户信息
* localhost:8080/user/8
*/
@DeleteMapping("/user/{id}")
public String delete(@PathVariable("id") Integer id){
int result = userMapper.delete(id);
if(result == 1){
return "success";
}
return "fail";
}
/**
* 根据id查询用户的所有电话信息(一对多)
* localhost:8080/user/phone/1
*/
@GetMapping("/user/phone/{id}")
public User selectPhoneById(@PathVariable("id") Integer id){
User user = userMapper.selectPhoneById(id);
return user;
}
/**
* 根据id查询用户选择的运营商(多对多)
* localhost:8080/user/combo/1
*/
@GetMapping("/user/combo/{id}")
public User selectComboById(@PathVariable("id") Integer id){
User user = userMapper.selectComboById(id);
return user;
}
}
4. 测试
根据id查询用户选择的运营商-GET