springboot整合mybatis-plus實現多表分頁查詢的示例代碼

<dependency>
      <groupId>com.baomidou</groupId>
      <artifactId>mybatis-plus-boot-starter</artifactId>
      <version>3.1.1</version>
    </dependency>
     <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>2.0.1</version>
    </dependency>

server:
 port: 8080
spring:
 datasource:
  url: jdbc:mysql://localhost:3306/mybatisplus?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=UTC
  username: root
  password: 數據庫密碼
mybatis:
 mapper-locations: classpath*:mapper/*.xml

mybatis-plus:
 mapper-locations: classpath:/mapper/*Mapper.xml
logging:
 level:
  com.tuanzi.*: debug

省略import
@EnableTransactionManagement
@Configuration
@MapperScan("com.tuanzi.*.mapper*")
public class MybatisPlusConfig {

  /**
   * 分頁插件
   */
  @Bean
  public PaginationInterceptor paginationInterceptor(){
    return new PaginationInterceptor();
  }
}

@RestController
@RequestMapping("/user")
public class UserController {

  @Autowired
  UserService userService;

  /**
   * 多表關聯，分頁查詢(1對1)
   * @param page
   * @return
   */
  @RequestMapping("/findAll")
  public Result<IPage<User>> findAll(@RequestBody Page<User> page){

     return userService.pages(page);

  }

  /**
   * 多表關聯，分頁查詢(1對多)
   * @param page
   * @return
   */
  @RequestMapping("/selectAll")
  public Result<IPage<User>> selectAll(@RequestBody Page<User> page){

    return userService.pageList(page);

  }
}

public interface UserService extends IService<User> {

  Result<IPage<User>> pages(Page<User> page);

  Result<IPage<User>> pageList(Page<User> page);
}

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {

  @Autowired
  UserMapper userMapper;
  @Override
  public Result<IPage<User>> pages(Page<User> page) {
    IPage<User> userIPage = userMapper.Pages(page);
    return Result.getSuccess("分頁查詢成功",userIPage);
  }

  @Override
  public Result<IPage<User>> pageList(Page<User> page) {
    IPage<User> userIPage = userMapper.pageList(page);
    return Result.getSuccess("分頁查詢成功",userIPage);
  }
}

@Mapper
@Repository
public interface UserMapper extends BaseMapper<User> {

  IPage<User> Pages(@Param("page") Page<User> page);

  IPage<User> pageList(@Param("page") Page<User> page);
}

 <!-- 一對一 通用查詢映射結果 -->
  <resultMap id="BaseResultMap1" type="com.tuanzi.user.entity.User">
    <result column="id" property="id" />
    <result column="name" property="name" />
    <result column="age" property="age" />
    <result column="email" property="email" />
    <!--assocication  一對一關聯查詢
        可以指定聯合的JavaBean對象
        property="work"指定哪個屬性是聯合的對象
        javaType:指定這個屬性對象的類型
      -->
    <association property="work" javaType="com.tuanzi.user.entity.Work">
      <result column="id" property="id" />
      <result column="position" property="position" />
      <result column="user_id" property="userId" />
    </association>
  </resultMap>

<!-- 一對多 通用查詢映射結果 -->
  <resultMap id="BaseResultMap2" type="com.tuanzi.user.entity.User">
    <result column="id" property="id" />
    <result column="name" property="name" />
    <result column="age" property="age" />
    <result column="email" property="email" />
    <!--
		collection定義關聯結合類型的屬性的封裝規則
		property="workList"指定哪個屬性是聯合的對象
		ofType：指定集合裡面元素的類型
		-->
    <collection property="workList" ofType="com.tuanzi.user.entity.Work">
      <result column="id" property="id" />
      <result column="position" property="position" />
      <result column="user_id" property="userId" />
    </collection>
  </resultMap>

<select id="Pages" resultMap="BaseResultMap1">
    select a.id id,a.name name,a.age age,a.email email,b.position position,b.user_id user_id from user a LEFT JOIN work b on a.id=b.user_id
  </select>
  <select id="pageList" resultMap="BaseResultMap2">
    select a.id id,a.name name,a.age age,a.email email,b.position position,b.user_id user_id from user a LEFT JOIN work b on a.id=b.user_id
  </select>