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
效果图：
最后附赠源码地址：demo
