MyBatis-Plus分页时排序的实现方法_Java教程

简介

说明

本文用示例介绍MyBtisPlus分页时排序的方法。

分页时排序的方法

后端OrderItems排序
后端Wrapper排序
前端指定排序

排序涉及到的类

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;
  ...
}

建库建表

DROP DATABASE IF EXISTS mp;
CREATE DATABASE mp DEFAULT CHARACTER SET utf8;
USE mp;

DROP TABLE IF EXISTS `t_user`;
SET NAMES utf8mb4;
CREATE TABLE `t_user`
(
  `id`           BIGINT(0) NOT NULL AUTO_INCREMENT,
  `user_name`    VARCHAR(64) NOT NULL COMMENT '用户名（不能重复）',
  `nick_name`    VARCHAR(64) NULL COMMENT '昵称（可以重复）',
  `email`        VARCHAR(64) COMMENT '邮箱',
  `create_time`  DATETIME(0) NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `update_time`  DATETIME(0) NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '修改时间',
  `deleted_flag` BIGINT(0) NOT NULL DEFAULT 0 COMMENT '0：未删除 其他：已删除',
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE KEY `index_user_name_deleted_flag` (`user_name`, `deleted_flag`),
  KEY `index_create_time`(`create_time`)
) ENGINE = InnoDB COMMENT = '用户';
INSERT INTO `t_user` VALUES (1, 'knife', '刀刃', 'abc@qq.com', '2021-01-23 09:33:36', '2021-01-23 09:33:36', 0);
INSERT INTO `t_user` VALUES (2, 'sky', '天蓝', '123@qq.com', '2021-01-24 18:12:21', '2021-01-24 18:12:21', 0);

执行后的结果：

MyBatis-Plus分页时排序的实现方法

依赖

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.3.12.RELEASE</version>
      <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.example</groupId>
  <artifactId>MyBatis-Plus_Simple</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>MyBatis-Plus_Simple</name>
  <description>Demo project for Spring Boot</description>

  <properties>
      <java.version>1.8</java.version>
  </properties>
  <dependencies>
      <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
          <groupId>com.baomidou</groupId>
          <artifactId>mybatis-plus-boot-starter</artifactId>
          <version>3.5.1</version>
          <artifactId>spring-boot-starter-test</artifactId>
          <scope>test</scope>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <groupId>org.projectlombok</groupId>
          <artifactId>lombok</artifactId>
          <groupId>com.github.xiaoymin</groupId>
          <artifactId>knife4j-spring-boot-starter</artifactId>
          <version>3.0.3</version>
  </dependencies>
  <build>
      <plugins>
          <plugin>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-maven-plugin</artifactId>
          </plugin>
      </plugins>
  </build>
</project>

配置

application.yml

spring:
datasource:
  driver-class-name: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://127.0.0.1:3306/mp?characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
  username: root
  password: 222333

#mybatis-plus配置控制台打印完整带参数SQL语句
mybatis-plus:
configuration:
  log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

分页插件的配置（必须）

package com.example.demo.config;
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;
  }
}

代码

Entity

package com.example.demo.user.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableLogic;
import com.baomidou.mybatisplus.annotation.TableName;
import com.baomidou.mybatisplus.extension.activerecord.Model;
import lombok.Data;
import java.time.LocalDateTime;
@Data
@TableName(value = "t_user")
public class User {
  @TableId(value = "id", type = IdType.AUTO)
  private Long id;
  /**
   * 用户名（不能重复）
   */
  private String userName;
   * 昵称（可以重复）
  private String nickName;
   * 邮箱
  private String email;
   * 创建时间
  private LocalDateTime createTime;
   * 修改时间
  private LocalDateTime updateTime;
   * 0：未删除 其他：已删除
  @TableLogic(delval = "id")
  private Long deletedFlag;
}

Service

接口

package com.example.demo.user.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.user.entity.User;
public interface UserService extends IService<User> {
}

实现

package com.example.demo.user.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.user.entity.User;
import com.example.demo.user.mapper.UserMapper;
import com.example.demo.user.service.UserService;
import org.springframework.stereotype.Service;
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
}

Controller

package com.example.demo.user.controller;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.metadata.OrderItem;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.example.demo.user.entity.User;
import com.example.demo.user.service.UserService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@Api(tags = "排序")
@RestController
@RequestMapping("sort")
public class SortController {
  @Autowired
  private UserService userService;
  @ApiOperation("默认顺序")
  @GetMapping("defaultOrder")
  public IPage<User> defaultOrder(Page<User> page) {
      return userService.page(page);
  }
  @ApiOperation("通过orderItems")
  @GetMapping("orderItems")
  public IPage<User> orderItems(Page<User> page) {
      page.addOrder(OrderItem.desc("create_time"));
      // 可以指定多列。比如下边这个：按create_time排序，若create_time相同，则按id排序
      // page.addOrder(OrderItem.desc("create_time"), OrderItem.asc("id"));
  @ApiOperation("通过wrapper")
  @GetMapping("wrapper")
  public IPage<User> wrapper(Page<User> page) {
      LambdaQueryWrapper<User> queryWrapper = Wrappers.<User>lambdaQuery();
      // 按create_time排序，若create_time相同，则按id排序
      queryWrapper.orderByDesc(User::getCreateTime);
      queryWrapper.orderByAsc(User::getId);
      return userService.page(page, queryWrapper);
  @ApiOperation("前端指定顺序")
  @GetMapping("byFrontEnd")
  public IPage<User> byFrontEnd(Page<User> page) {
}