springboot整合mybatis-plus实现多表分页查询的示例代码

程序员文章站 2022-04-01 08:41:33

1.新建一个springboot工程2.需要导入mybatis和mybatis-plus的依赖文件 com.baomidou...

1.新建一个springboot工程

2.需要导入mybatis和mybatis-plus的依赖文件

<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>

3.application.yml配置文件

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: 数据库密码
mybatis:
 mapper-locations: classpath*:mapper/*.xml

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

4.首先我们需要写一个类来配置分页插件

省略import
@enabletransactionmanagement
@configuration
@mapperscan("com.tuanzi.*.mapper*")
public class mybatisplusconfig {

  /**
   * 分页插件
   */
  @bean
  public paginationinterceptor paginationinterceptor(){
    return new paginationinterceptor();
  }
}

5.controller类

@restcontroller
@requestmapping("/user")
public class usercontroller {

  @autowired
  userservice userservice;

  /**
   * 多表关联，分页查询(1对1)
   * @param page
   * @return
   */
  @requestmapping("/findall")
  public result<ipage<user>> findall(@requestbody page<user> page){

     return userservice.pages(page);

  }

  /**
   * 多表关联，分页查询(1对多)
   * @param page
   * @return
   */
  @requestmapping("/selectall")
  public result<ipage<user>> selectall(@requestbody page<user> page){

    return userservice.pagelist(page);

  }
}

6.service类

public interface userservice extends iservice<user> {

  result<ipage<user>> pages(page<user> page);

  result<ipage<user>> pagelist(page<user> page);
}

7.service实现类

@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("分页查询成功",useripage);
  }

  @override
  public result<ipage<user>> pagelist(page<user> page) {
    ipage<user> useripage = usermapper.pagelist(page);
    return result.getsuccess("分页查询成功",useripage);
  }
}

8.mapper接口

注意!!: 如果入参是有多个,需要加注解指定参数名才能在xml中取值

@mapper
@repository
public interface usermapper extends basemapper<user> {

  ipage<user> pages(@param("page") page<user> page);

  ipage<user> pagelist(@param("page") page<user> page);
}

9.xml文件

一对一关联

 <!-- 一对一 通用查询映射结果 -->
  <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  一对一关联查询
        可以指定联合的javabean对象
        property="work"指定哪个属性是联合的对象
        javatype:指定这个属性对象的类型
      -->
    <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>

一对多关联

<!-- 一对多 通用查询映射结果 -->
  <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定义关联结合类型的属性的封装规则
		property="worklist"指定哪个属性是联合的对象
		oftype：指定集合里面元素的类型
		-->
    <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>

sql语句：

<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>

10.这样就基本完成了！我这里省略了实体类

我们运行一下，用postman测试一下结果
这里我们需要传2个参数，当然我们也可以不用传，因为mybatis-plus有默认值
来看下mybatis-plus的page源码

springboot整合mybatis-plus实现多表分页查询的示例代码