mybatis-plus分页+多表查询

ゝ一世哀愁。 2023-01-22 10:55 29阅读 0赞

## 在springboot中使用mybatis-plus ##

在pom文件导入

<dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.2.0</version>
            </dependency>
            
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.19</version>
            </dependency>

2.在papplication.properties配置数据库信息

server.port=8088
    
    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/activity_service?characterEncoding=UTF-8
    spring.datasource.username=activity_service
    spring.datasource.password=123213

3.编写mapper接口继承BaseMapper<表的实体类>

package com.activity.mapper;
    
    import com.activity.entity.User;
    import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    import org.apache.ibatis.annotations.Param;
    
    import java.util.List;
    
    public interface UserMapper extends BaseMapper<User> { 
    
    }

4.使用分页插件  
先新建一个类,带上分页插件

package com.activity.common.Page;
    
    import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    @Configuration
    public class Page { 
        //分页插件
        @Bean
        public PaginationInterceptor paginationInterceptor(){ 
            return new PaginationInterceptor();
        }
    }

在test测试文件中

package com.activity;
    
    import com.activity.entity.Aclog;
    import com.activity.mapper.AclogMapper;
    import com.baomidou.mybatisplus.core.metadata.IPage;
    import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
    import org.junit.jupiter.api.Test;
    import org.springframework.boot.test.context.SpringBootTest;
    
    import javax.annotation.Resource;
    import java.util.List; @SpringBootTest class ManagementApplicationTests { 
    
    
        @Resource
        private AclogMapper aclogMapper; @Test void contextLoads() { 
            //1.创建对象
            //2.传入两个参数,
            Page<Aclog> page=new Page<>(2,5);
            //调用map的分页查询方法
            //调用mp分页查询过程中,底层封装
            //把分页所有数据封装到page对象里面
            IPage<Aclog> aclogIPage = aclogMapper.selectPage(page, null);
            List<Aclog> records = aclogIPage.getRecords(); for(Aclog aclog:records){ 
                System.out.println(aclog);
            }
    
            //通过page对象获取到分页
            System.out.println(page.getCurrent());//当前页
            System.out.println(page.getRecords());//每夜数据list集合
            System.out.println(page.getSize());//每页现实记录数
            System.out.println(page.getTotal());//总记录数
            System.out.println(page.getPages());//总页数
            System.out.println(page.hasNext());
            System.out.println(page.hasPrevious());
    
        }
    
    }

![查询结果][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTA3OTk3NA_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTA3OTk3NA_size_16_color_FFFFFF_t_70]: /images/20221020/a36a82bb4dfc4a818cf1303c01d24a4a.png