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Mybatis-Plus--分页/多表联合查询--方法/使用/教程/实例

才德的女子 2022-02-25 阅读 47
数据库mybatisplussqlspringapache


​

简介

        本文用实例介绍MybatisPlus的分页以及多表联合查询的方法。

公共代码

​分页插件新写法（3.4.0及之后）​

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;

@Configuration
public class MybatisPlusConfig {

    // 分页插件
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

​分页插件老写法（3.4.0之前）​

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {

    // 分页插件
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        // 设置请求的页面大于最大页后操作， true调回到首页，false 继续请求  默认false
        // paginationInterceptor.setOverflow(false);
        // 设置最大单页限制数量，默认 500 条，-1 不受限制
        // paginationInterceptor.setLimit(500);
        // 开启 count 的 join 优化,只针对部分 left join
        paginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));
        return paginationInterceptor;
    }
}

​entity​

@Data
@TableName("t_question")
public class Question implements Serializable {

    private static final long serialVersionUID = 1L;

    // 问答主键id
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    // 学生外键id
    @TableField("student_id")
    private Integer studentId;

    // 问题内容
    private String content;

    // 问题悬赏的积分
    private Integer value;
}
@Data
@TableName("t_student")
public class Student implements Serializable {

    private static final long serialVersionUID = 1L;

    // 学生主键id
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    // 学生名称
    private String name;

    // 学生积分数
    private Integer points;
}

​VO​

@Data
public class QuestionStudentVO implements Serializable {
    // 问题主键id
    private Integer id;

    // 问题内容
    private String content;

    // 问题悬赏的积分
    private Integer value;

    // 学生外键id
    private Integer studentId;

    // 学生名字
    private List<String> name;

    // 学生积分
    private Integer points;
}

​启动类​

package com.example;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.example.mapper")
public class MpPlusApplication {
    public static void main(String[] args) {
        SpringApplication.run(MpPlusApplication.class, args);
    }
}

​sql​

USE mp;
DROP TABLE IF EXISTS `t_question`;
CREATE TABLE `t_question` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `student_id` int(11) DEFAULT NULL,
  `content` varchar(64) DEFAULT NULL,
  `value` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1002 DEFAULT CHARSET=utf8;


BEGIN;
INSERT INTO `t_question` VALUES ('1001', '1', 'this is question content', '10');
INSERT INTO `t_question` VALUES ('1002', '2', 'this is question content', '30');
COMMIT;

DROP TABLE IF EXISTS `t_student`;
CREATE TABLE `t_student` (
  `id` int(11) NOT NULL,
  `name` varchar(64) DEFAULT NULL,
  `points` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

BEGIN;
INSERT INTO `t_student` VALUES ('1', 'Iron Man', '201');
INSERT INTO `t_student` VALUES ('2', 'Jarvis', '100');
INSERT INTO `t_student` VALUES ('3', 'Tony', '300');
COMMIT;

​分页插件 ​

package com.example.conf;

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@EnableTransactionManagement
@Configuration
public class MybatisPlusConfig {

    // 分页插件
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }
}

多表查询

​其他网址​

​​mybatis Plus 多表联合查询​​

代码

​mapper​

package com.example.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.entity.Question;
import com.example.vo.QuestionStudentVO;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface QuestionMapper extends BaseMapper<Question> {
    @Select("SELECT t_question.*,t_student.`name`,t_student.`points` " + 
            " FROM t_question,t_student " +
            " WHERE t_question.student_id=t_student.id")
    List<QuestionStudentVO> getQuestionStudent();

    @Select("SELECT t_student.name " + 
            " FROM t_question,t_student " +
            " WHERE t_question.student_id = #{id} " +
            "    AND t_question.student_id=t_student.id")
    List<String> getStudentNameByQuestionId(@Param("id") Long id);

    @Select("SELECT t_student.name " + 
            " FROM t_question,t_student " +
            " ${ew.customSqlSegment} " +
            "    AND t_question.student_id=t_student.id")
    List<String> getStudentNamesByQuestionIds(@Param("ew") Wrapper wrapper);
}

 ​controller​

package com.example.controller;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.entity.Student;
import com.example.mapper.QuestionMapper;
import com.example.vo.QuestionStudentVO;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Collections;
import java.util.List;

@RestController
@RequestMapping("/common")
public class CommonController {
    @Autowired
    private QuestionMapper questionMapper;

    @RequestMapping("/getAllQuestionWithStudent")
    public List<QuestionStudentVO> getAllQuestionWithStudent() {
        List<QuestionStudentVO> questionStudent = questionMapper.getQuestionStudent();
        if (questionStudent == null) {
            return Collections.emptyList();
        }
        return questionStudent;
    }

    @RequestMapping("/getStudentNameByQuestionId")
    public List<String> getStudentNameById(Long id) {
        return questionMapper.getStudentNameByQuestionId(id);
    }

    @RequestMapping("/getStudentNamesByQuestionIds")
    public List<String> getStudentNamesByQuestionIds(Long[] ids) {
        List<Long> questionIds = Arrays.asList(ids);
        return questionMapper.getStudentNamesByQuestionIds(questionIds);
    }
}

​测试​

​postman访问：​​http://localhost:8080/common/getAllQuestionWithStudent​​

postman结果

[
    {
        "id": 1001,
        "studentId": 1,
        "name": null,
        "points": 201,
        "content": "this is question content",
        "value": 10
    },
    {
        "id": 1002,
        "studentId": 2,
        "name": null,
        "points": 100,
        "content": "this is question content",
        "value": 30
    }
]

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@597f87ec] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1471701683 wrapping com.mysql.cj.jdbc.ConnectionImpl@7b7782db] will not be managed by Spring
==>  Preparing: SELECT t_question.*,t_student.`name`,t_student.points FROM t_question,t_student WHERE t_question.student_id=t_student.id 
==> Parameters: 
<==    Columns: id, student_id, content, value, name, points
<==        Row: 1001, 1, this is question content, 10, Iron Man, 201
<==        Row: 1002, 2, this is question content, 30, Jarvis, 100
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@597f87ec]

 ​postman访问：​​http://localhost:8080/common/getStudentNameByQuestionId?id=1​​

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@427b93c6] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1287419385 wrapping com.mysql.cj.jdbc.ConnectionImpl@7b7782db] will not be managed by Spring
==>  Preparing: SELECT t_student.name FROM t_question,t_student WHERE t_question.student_id = ? AND t_question.student_id=t_student.id 
==> Parameters: 1(Long)
<==    Columns: name
<==        Row: Iron Man
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@427b93c6]

postman结果

[
    "Iron Man"
]

 ​postman访问：​​http://localhost:8080/common/getStudentNamesByQuestionIds?ids=1,2​​

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@63dc1476] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1830549117 wrapping com.mysql.cj.jdbc.ConnectionImpl@7b7782db] will not be managed by Spring
==>  Preparing: SELECT t_student.name FROM t_question,t_student WHERE (t_question.student_id IN (?,?)) AND t_question.student_id=t_student.id 
==> Parameters: 1(Long), 2(Long)
<==    Columns: name
<==        Row: Iron Man
<==        Row: Jarvis
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@63dc1476]

postman结果

[
    "Iron Man",
    "Jarvis"
]

单表分页

​其他网址​

​​Mybatis-Plus官网（分页）​​

​​Mybatis Plus 使用详解 - 六层楼 -​​

代码 

​mapper​

package com.example.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.entity.Question;
import com.example.vo.QuestionStudentVO;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface QuestionMapper extends BaseMapper<Question> {
}

​Service​

package com.example.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.entity.Student;

public interface StudentService extends IService<Student> {
}
package com.example.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.entity.Student;
import com.example.mapper.StudentMapper;
import com.example.service.StudentService;
import org.springframework.stereotype.Service;

@Service
public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student> implements StudentService {
}

​Controller​

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;

@RestController
@RequestMapping("/common")
public class CommonController {
    @Autowired
    private QuestionService questionService;

    @Autowired
    private StudentService studentService;

    @RequestMapping("/getAllStudent")
    public IPage<Student> getAllStudent(Page<Student> page) {
        // 如果查出来为空，会返回入参page里边的数据，比如：current，size等。不需要自己判空。
        return studentService.page(page,
                    new LambdaQueryWrapper<Student>().orderByDesc(Student::getName)
                );
    }

    @RequestMapping("/getAllStudentByName")
    public IPage<Student> getAllStudentByName(Page<Student> page) {
        // 如果查出来为空，会返回入参page里边的数据，比如：current，size等。不需要自己判空。
        return studentService.lambdaQuery().eq(Student::getName, "Jarvis").page(page);
    }

    @RequestMapping("/getAllStudentByNameNo")
    public IPage<Student> getAllStudentByNameNo(Page<Student> page) {
        // 如果查出来为空，会返回入参page里边的数据，比如：current，size等。不需要自己判空。
        return studentService.lambdaQuery().eq(Student::getName, "NO NO").page(page);
    }

}

​测试​

postman访问：​​http://localhost:8080/common/getAllStudent​​

​使用第1条（无条件，会查出所有）​

postman结果

{
    "records": [
        {
            "id": 1,
            "name": "Iron Man",
            "points": 201
        },
        {
            "id": 2,
            "name": "Jarvis",
            "points": 100
        },
        {
            "id": 3,
            "name": "Tony",
            "points": 300
        }
    ],
    "total": 3,
    "size": 10,
    "current": 1,
    "orders": [],
    "optimizeCountSql": true,
    "hitCount": false,
    "searchCount": true,
    "pages": 1
}

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5810d535] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1456943175 wrapping com.mysql.cj.jdbc.ConnectionImpl@61b976ac] will not be managed by Spring
JsqlParserCountOptimize sql=SELECT  id,name,points  FROM t_student
==>  Preparing: SELECT COUNT(1) FROM t_student 
==> Parameters: 
<==    Columns: COUNT(1)
<==        Row: 3
==>  Preparing: SELECT id,name,points FROM t_student LIMIT ?,? 
==> Parameters: 0(Long), 10(Long)
<==    Columns: id, name, points
<==        Row: 1, Iron Man, 201
<==        Row: 2, Jarvis, 100
<==        Row: 3, Tony, 300
<==      Total: 3
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5810d535]

​使用第2条（指定条件，有匹配到的）：​​http://localhost:8080/common/getAllStudentByName?size=5&current=1​​

postman结果

{
    "records": [
        {
            "id": 2,
            "name": "Jarvis",
            "points": 100
        }
    ],
    "total": 1,
    "size": 5,
    "current": 1,
    "orders": [],
    "optimizeCountSql": true,
    "hitCount": false,
    "searchCount": true,
    "pages": 1
}

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6b8778dc] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@594281656 wrapping com.mysql.cj.jdbc.ConnectionImpl@61b976ac] will not be managed by Spring
JsqlParserCountOptimize sql=SELECT  id,name,points  FROM t_student 

 WHERE (name = ?)
==>  Preparing: SELECT COUNT(1) FROM t_student WHERE (name = ?) 
==> Parameters: Jarvis(String)
<==    Columns: COUNT(1)
<==        Row: 1
==>  Preparing: SELECT id,name,points FROM t_student WHERE (name = ?) LIMIT ?,? 
==> Parameters: Jarvis(String), 0(Long), 5(Long)
<==    Columns: id, name, points
<==        Row: 2, Jarvis, 100
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6b8778dc]

​使用第3条（指定条件，没有匹配到的）：​​http://localhost:8080/common/getAllStudentByNameNo​​

postman结果

{
    "records": [],
    "total": 0,
    "size": 10,
    "current": 1,
    "orders": [],
    "optimizeCountSql": true,
    "hitCount": false,
    "searchCount": true,
    "pages": 0
}

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6418d8d0] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1158294948 wrapping com.mysql.cj.jdbc.ConnectionImpl@61b976ac] will not be managed by Spring
JsqlParserCountOptimize sql=SELECT  id,name,points  FROM t_student 

 WHERE (name = ?)
==>  Preparing: SELECT COUNT(1) FROM t_student WHERE (name = ?) 
==> Parameters: NO NO(String)
<==    Columns: COUNT(1)
<==        Row: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6418d8d0]

多表分页

​其他网址​

​​最简单的 MyBatis Plus 的多表联接、分页查询实现方法_IT小村-​​

代码

​Mapper ​

package com.example.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.entity.Question;
import com.example.vo.QuestionStudentVO;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface QuestionMapper extends BaseMapper<Question> {
    @Select("SELECT t_question.*,t_student.* " +
            " FROM t_question,t_student " +
            " WHERE t_question.student_id=t_student.id")
    List<QuestionStudentVO> getQuestionStudentPage (Page<QuestionStudentVO> page);
}

​Service​

package com.example.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.entity.Question;
import com.example.vo.QuestionStudentVO;

import java.util.List;

public interface QuestionService extends IService<Question> {
    IPage<QuestionStudentVO> getQuestionStudentPage (Page<QuestionStudentVO> page);
}
package com.example.service.impl;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.entity.Question;
import com.example.mapper.QuestionMapper;
import com.example.service.QuestionService;
import com.example.vo.QuestionStudentVO;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class QuestionServiceImpl extends ServiceImpl<QuestionMapper, Question> implements QuestionService {
    //下边的this.baseMapper都可以用自动注入的QuestionMapper替换

    @Override
    public Page<QuestionStudentVO> getQuestionStudentPage (Page<QuestionStudentVO> page) {
        return page.setRecords(this.baseMapper.getQuestionStudentPage(page));
    }
}

​Controller​

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;

@RestController
@RequestMapping("/common")
public class CommonController {
    @Autowired
    private QuestionService questionService;

    @Autowired
    private StudentService studentService;

    @RequestMapping("/getAllQuestionWithStudentByPage")
    public IPage<QuestionStudentVO> getAllQuestionWithStudentByPage(Page<QuestionStudentVO> page) {
        IPage<QuestionStudentVO> questionStudent = questionService.getQuestionStudentPage (page);
        return questionStudent;
    }
}

​测试​

postman访问：

​​http://localhost:8080/common/getAllQuestionWithStudentByPage?current=1&size=2​​

postman结果（可见数组或List无法直接赋值。）

{
    "records": [
        {
            "id": 1001,
            "studentId": 1,
            "name": null,
            "points": 201,
            "content": "this is question content",
            "value": 10
        },
        {
            "id": 1002,
            "studentId": 2,
            "name": null,
            "points": 100,
            "content": "this is question content",
            "value": 30
        }
    ],
    "total": 2,
    "size": 2,
    "current": 1,
    "orders": [],
    "optimizeCountSql": true,
    "hitCount": false,
    "searchCount": true,
    "pages": 1
}

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@46bd5ef7] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@1676586413 wrapping com.mysql.cj.jdbc.ConnectionImpl@61b976ac] will not be managed by Spring
JsqlParserCountOptimize sql=SELECT t_question.*,t_student.* FROM t_question,t_student WHERE t_question.student_id=t_student.id
==>  Preparing: SELECT COUNT(1) FROM t_question, t_student WHERE t_question.student_id = t_student.id 
==> Parameters: 
<==    Columns: COUNT(1)
<==        Row: 2
==>  Preparing: SELECT t_question.*,t_student.* FROM t_question,t_student WHERE t_question.student_id=t_student.id LIMIT ?,? 
==> Parameters: 0(Long), 2(Long)
<==    Columns: id, student_id, content, value, id, name, points
<==        Row: 1001, 1, this is question content, 10, 1, Iron Man, 201
<==        Row: 1002, 2, this is question content, 30, 2, Jarvis, 100
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@46bd5ef7]

​手动包装Page​

        Mybatis Plus分页查询的重点在于Page这个包装类。上边的多表分页查询用了page.setRecords其实就是手动包装的。再把代码拿过来看一下

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;

@Service
public class QuestionServiceImpl extends ServiceImpl<QuestionMapper, Question> implements QuestionService {
    @Override
    public Page<QuestionStudentVO> getQuestionStudentPage (Page<QuestionStudentVO> page) {
        return page.setRecords(this.baseMapper.getQuestionStudentPage(page));
    }
}

​this.baseMapper.getQuestionStudentPage(page)​

这个执行完之后，会将page的total等进行赋值。然后外部的page.setRecords会将其返回值设置到page里边去。

排序

排序涉及到Page类的List<OrderItem> orders;成员，OrderItem定义如下：

public class OrderItem implements Serializable {
    private static final long serialVersionUID = 1L;

    //需要进行排序的字段
    private String column;

    // 是否正序排列，默认 true
    private boolean asc = true;
    ...
}

前端指定排序

​Controller​

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;

@RestController
@RequestMapping("/common")
public class CommonController {
    @Autowired
    private StudentService studentService;

    @RequestMapping("/getAllStudentInOrder")
    public IPage<Student> getAllStudentInOrder(Page<Student> page) {
        IPage<Student> students = studentService.page(page);
        if (students == null) {
            return page;
        }
        return students;
    }
}

​测试​

postman访问：​​http://localhost:8080/common/getAllStudentInOrder?current=1&size=2​​

postman的body

orders[0].column

orders[0].asc

Mybatis-Plus--分页/多表联合查询--方法/使用/教程/实例_sql

postman的结果

{
    "records": [
        {
            "id": 3,
            "name": "Tony",
            "points": 300
        },
        {
            "id": 2,
            "name": "Jarvis",
            "points": 100
        }
    ],
    "total": 3,
    "size": 2,
    "current": 1,
    "orders": [
        {
            "column": "name",
            "asc": false
        }
    ],
    "optimizeCountSql": true,
    "hitCount": false,
    "searchCount": true,
    "pages": 2
}

后端结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@551ee9d2] was not registered for synchronization because synchronization is not active
JDBC Connection [HikariProxyConnection@726462971 wrapping com.mysql.cj.jdbc.ConnectionImpl@61b976ac] will not be managed by Spring
JsqlParserCountOptimize sql=SELECT  id,name,points  FROM t_student
==>  Preparing: SELECT COUNT(1) FROM t_student 
==> Parameters: 
<==    Columns: COUNT(1)
<==        Row: 3
==>  Preparing: SELECT id, name, points FROM t_student ORDER BY name DESC LIMIT ?,? 
==> Parameters: 0(Long), 2(Long)
<==    Columns: id, name, points
<==        Row: 3, Tony, 300
<==        Row: 2, Jarvis, 100
<==      Total: 2
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@551ee9d2]

后端OrderItems排序

@GetMapping("/page")
public IPage<User> getUserPage(Page<User> page) {
    page.addOrder(OrderItem.desc("create_time"), OrderItem.asc("id"));
    return UserService.page(page);
}

后端Wrapper排序

@GetMapping("/page")
public IPage<User> getUserPage(Page<User> page) {
    LambdaQueryWrapper<User> queryWrapper = Wrappers.<User>lambdaQuery();
    queryWrapper.orderByDesc(User::getCreateTime);
    queryWrapper.orderByAsc(User::getId);
    return UserService.page(page, queryWrapper);
}

其他网址

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mybatis-plus的使用 ------ 进阶 -

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