Spring Boot 2.X 集成 Mybatis PageHelper 分页插件解决一对多分页查询问题
文章目录
- 1 摘要
- 2 官方文档
- 3 核心依赖
- 4 核心代码
- 4.1 方法应用
- 4.2 Mapper 文件
- 4.3 DAO 接口
- 4.3 所有相关类概览
- 5 数据库SQL
- 6 测试结果
- 7 参考文档推荐
- 8 Github 源码
1 摘要
每个项目中都会用到分页查询，这一技术具有高度的复用性，为了避免每次创建新项目时重新编写一边分页查询，或者因为项目的数据库更换而重新编写分页代码,将分页查询提取出来封装成专门的第三方库就显得十分必要。本文将介绍基于 Spring Boot 2.X 集成 Mybatis PageHelper 分页插件。
2 官方文档
MyBatis Pagination - PageHelper
3 核心依赖
./pom.xml
./demo-dao/pom.xml
<dependency>
<groupId>com.github.pagehelpergroupId>
<artifactId>pagehelper-spring-boot-starterartifactId>
<version>${mybatis.pagehelper.version}version>
dependency>
其中 ${mybatis.pagehelper.version} 的版本为 1.2.12
4 核心代码
4.1 方法应用
./demo-service/src/main/java/com/ljq/demo/springboot/service/impl/ArticleServiceImpl.java
package com.ljq.demo.springboot.service.impl;
import cn.hutool.core.bean.BeanUtil;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.ljq.demo.springboot.common.api.ApiResult;
import com.ljq.demo.springboot.common.page.QueryUtil;
import com.ljq.demo.springboot.dao.article.ArticleDao;
import com.ljq.demo.springboot.entity.ArticleEntity;
import com.ljq.demo.springboot.service.ArticleService;
import com.ljq.demo.springboot.vo.article.ArticleListParam;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
/**
* 文章表业务层具体实现类
*
* @author junqiang.lu
* @date 2019-11-25 14:01:38
*/
@Service("articleService")
@Transactional(rollbackFor = {Exception.class})
@Slf4j
public class ArticleServiceImpl implements ArticleService {
@Autowired
private ArticleDao articleDao;
/**
* 查询列表
*
* @param articleListParam
* @return
* @throws Exception
*/
@Override
public ApiResult list(ArticleListParam articleListParam) throws Exception {
long start = System.currentTimeMillis();
QueryUtil queryMap = new QueryUtil(BeanUtil.beanToMap(articleListParam, false, true));
PageInfo<ArticleEntity> pageInfo = PageHelper.startPage(articleListParam.getCurrPage(), articleListParam.getPageLimit())
.setOrderBy(articleListParam.getProperties() + " " + articleListParam.getDirection())
.doSelectPageInfo(() -> articleDao.queryListPage(queryMap));
long end = System.currentTimeMillis();
log.info("查询耗时: {}", (end - start));
return ApiResult.success(pageInfo);
}
}
关于 PageHelper 的一些方法说明:
startPage: 设置查询起始点与每页显示条数
setOrderBy: 设置排序规则
doSelectPageInfo: 需要执行的查询语句，Mybatis Mapper 中定义的接口(支持 lambda 表达式)，返回的结果是分页信息PageInfo(包含结果列表以及分页参数)
doSelectPage: 也是执行查询语句，与 doSelectPageInfo 一样，只是返回结果不同，doSelectPage 返回的是 Page, 如果将这个结果返回至前端，则只有数据列表，而没有分页信息。Page 可转化为 PageInfo
注意 : 方法顺序必须是 startPage -> setOrderBy -> doSelectPage ,若将 setOrderBy 放在 doSelectPage 后边，则排序不生效(亲测结果是这样的)
4.2 Mapper 文件
../demo-dao/src/main/resources/mapper/ArticleDao.xml
<mapper namespace="com.ljq.demo.springboot.dao.article.ArticleDao">
<resultMap type="com.ljq.demo.springboot.entity.ArticleEntity" id="articleMap">
<result property="id" column="id"/>
<result property="title" column="title"/>
<result property="content" column="content"/>
<collection property="tagList" column="id" javaType="java.util.List" ofType="com.ljq.demo.springboot.entity.ArticleTagEntity"
select="com.ljq.demo.springboot.dao.article.ArticleTagDao.queryTagsByArticleId">
<id property="id" column="id" />
<result property="tagName" column="tag_name" />
collection>
resultMap>
<sql id="article_base_field">
a.`id`,
a.`title`,
a.`content`
sql>
<sql id="article_list_field">
<include refid="article_base_field" />
,
at.`id` at_id,
at.`tag_name` at_tag_name
sql>
<select id="queryListPage" parameterType="java.util.Map" resultMap="articleMap">
SELECT
<include refid="article_base_field" />
FROM article a
LEFT JOIN `article_to_tag` att ON att.article_id = a.id
LEFT JOIN `article_tag` at ON at.id = att.tag_id
WHERE 1 = 1
<if test="title != null and '' != title">
AND a.title LIKE CONCAT(CONCAT("%", #{title}), "%")
if>
<if test="articleTag != null and '' != articleTag">
AND at.tag_name LIKE CONCAT(CONCAT("%", #{articleTag}), "%")
if>
GROUP BY a.id
select>
mapper>
../demo-dao/src/main/resources/mapper/ArticleTagDao.xml
<mapper namespace="com.ljq.demo.springboot.dao.article.ArticleTagDao">
<resultMap type="com.ljq.demo.springboot.entity.ArticleTagEntity" id="articleTagMap">
<result property="id" column="id"/>
<result property="tagName" column="tag_name"/>
resultMap>
<sql id="article_tag_base_field">
at.`id`,
at.`tag_name`
sql>
<select id="queryTagsByArticleId" parameterType="long" resultMap="articleTagMap">
SELECT
<include refid="article_tag_base_field" />
FROM `article_to_tag` att
LEFT JOIN `article_tag` at ON at.id = att.tag_id
LEFT JOIN `article` a ON a.id = att.article_id
WHERE a.id = #{id}
select>
mapper>
注意: 在一对多的关系中，可以使用 collection 来对查询结果进行封装。在 collection 标签中有 select 属性，用于将一个子查询结果封装到 resultMap 中，这个查询可以为本 Mapper 文件中的查询，也可以是其他 Mapper 文件的查询，如果为其他 Mapper 中的查询，则需要指定具体的 Mapper ，具体参考示例中ArticleDao.xml的代码
4.3 DAO 接口
../demo-dao/src/main/java/com/ljq/demo/springboot/dao/article/ArticleTagDao.java
package com.ljq.demo.springboot.dao.article;
import com.ljq.demo.springboot.dao.BaseDao;
import com.ljq.demo.springboot.entity.ArticleTagEntity;
import org.apache.ibatis.annotations.Param;
import org.springframework.stereotype.Repository;
import java.util.List;
/**
* 文章标签表
*
* @author junqiang.lu
* @date 2019-11-25 14:01:38
*/
@Repository
public interface ArticleTagDao extends BaseDao<ArticleTagEntity> {
/**
* 查询某一篇文章的标签(列表)
*
* @param articleId
* @return
*/
List<ArticleTagEntity> queryTagsByArticleId(@Param("articleId") long articleId);
}
../demo-dao/src/main/java/com/ljq/demo/springboot/dao/article/ArticleDao.java
package com.ljq.demo.springboot.dao.article;
import com.ljq.demo.springboot.dao.BaseDao;
import com.ljq.demo.springboot.entity.ArticleEntity;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Map;
/**
* 文章表
*
* @author junqiang.lu
* @date 2019-11-25 14:01:38
*/
@Repository
public interface ArticleDao extends BaseDao<ArticleEntity> {
/**
* 查询列表
*
* @param queryMap
* @return
*/
List<ArticleEntity> queryListPage(Map<String, Object> queryMap);
}
4.3 所有相关类概览
数据模型(实体类):
../demo-model/src/main/java/com/ljq/demo/springboot/entity/ArticleEntity.java
../demo-model/src/main/java/com/ljq/demo/springboot/entity/ArticleTagEntity.java
../demo-model/src/main/java/com/ljq/demo/springboot/entity/ArticleToTagEntity.java
../demo-model/src/main/java/com/ljq/demo/springboot/vo/article/ArticleListParam.java
数据持久层(DAO):
../demo-dao/src/main/java/com/ljq/demo/springboot/dao/article/ArticleTagDao.java
../demo-dao/src/main/java/com/ljq/demo/springboot/dao/article/ArticleDao.java
业务层:
../demo-service/src/main/java/com/ljq/demo/springboot/service/ArticleService.java
../demo-service/src/main/java/com/ljq/demo/springboot/service/impl/ArticleServiceImpl.java
控制层(Controller):
../demo-web/src/main/java/com/ljq/demo/springboot/web/controller/ArticleController.java
5 数据库SQL
../doc/sql/article-database-create.sql
/*==============================================================*/
/* DBMS name: MySQL 5.0 */
/* Created on: 2019/11/27 14:32:00 */
/*==============================================================*/
drop table if exists article;
drop table if exists article_tag;
drop table if exists article_to_tag;
/*==============================================================*/
/* Table: article */
/*==============================================================*/
create table article
(
id bigint unsigned not null auto_increment comment '文章 id,主键',
title varchar(100) not null default '' comment '文章标题',
content varchar(5000) not null default '' comment '文章内容',
primary key (id)
)
ENGINE = InnoDB
CHARSET = UTF8MB4;
alter table article comment '文章表';
/*==============================================================*/
/* Table: article_tag */
/*==============================================================*/
create table article_tag
(
id bigint unsigned not null auto_increment comment '文章标签 id,主键',
tag_name varchar(20) not null default '' comment '标签名称',
primary key (id)
)
ENGINE = InnoDB
CHARSET = UTF8MB4;
alter table article_tag comment '文章标签表';
/*==============================================================*/
/* Table: article_to_tag */
/*==============================================================*/
create table article_to_tag
(
id bigint unsigned not null auto_increment comment '文章-标签关联表 id,主键',
article_id bigint unsigned not null default 0 comment '文章 id',
tag_id bigint unsigned not null default 0 comment '标签 id',
primary key (id)
)
ENGINE = InnoDB
CHARSET = UTF8MB4;
alter table article_to_tag comment '文章-标签关联表';
测试数据:
../doc/sql/article-database-test.sql
-- 批量插入文章标签
INSERT INTO `article_tag`(`tag_name`) VALUES
('初级'),
('中级'),
('高级'),
('超高级'),
('spring'),
('springBoot'),
('springMVC');
-- 批量插入文章
INSERT INTO `article` (`title`, `content`) VALUES
('好风光', '今天天气好晴朗，处处好风光'),
('冰雨', '冷冷的冰雨在我脸上胡乱地拍，你就像一个刽子手把我出卖'),
('学习', '好好学习,天天向上'),
('静夜思', '窗前明月光，疑是地上霜。举头望明月，低头思故乡。'),
('冬日里的一把火', '你就像那一把火，熊熊火焰燃烧了我'),
('演员', '简单点，说话的方式简单点。递进的情绪请省略，你又不是个演员'),
('小苹果', '你是我的小丫小苹果，怎么爱你都不嫌多'),
('雨一直下', '雨一直下，气氛不算融洽');
-- 批量给文章添加标签
INSERT INTO `article_to_tag` (`article_id`, `tag_id`) VALUES
(1,1),
(1,2),
(1,4),
(2,3),
(2,5),
(3,6),
(4,7),
(5,1),
(5,2),
(5,3),
(6,4),
(6,1),
(6,5),
(6,7),
(7,6),
(7,1),
(8,3),
(8,6),
(8,7),
(8,4);
6 测试结果
请求接口:
http://127.0.0.1:8088/api/article/list?currPage=1&direction=desc&pageLimit=5&properties=id
后台日志:
2019-11-27 16:00:33 | INFO | http-nio-8088-exec-4 | com.ljq.demo.springboot.web.acpect.LogAspectLogAspect.java 68| [AOP-LOG-START]
requestMark: 04822886-af60-47ac-966f-0d8d6ea8c7fe
requestIP: 127.0.0.1
contentType:application/x-www-form-urlencoded
requestUrl: http://127.0.0.1:8088/api/article/list
requestMethod: GET
requestParams: currPage = [1];direction = [desc];pageLimit = [5];properties = [id];
targetClassAndMethod: com.ljq.demo.springboot.web.controller.ArticleController#list
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPage_COUNTBaseJdbcLogger.java 159| ==> Preparing: SELECT count(0) FROM (SELECT a.`id`, a.`title`, a.`content` FROM article a LEFT JOIN `article_to_tag` att ON att.article_id = a.id LEFT JOIN `article_tag` at ON at.id = att.tag_id WHERE 1 = 1 GROUP BY a.id) table_count
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPage_COUNTBaseJdbcLogger.java 159| ==> Parameters:
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPage_COUNTBaseJdbcLogger.java 159| <== Total: 1
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPageBaseJdbcLogger.java 159| ==> Preparing: SELECT a.`id`, a.`title`, a.`content` FROM article a LEFT JOIN `article_to_tag` att ON att.article_id = a.id LEFT JOIN `article_tag` at ON at.id = att.tag_id WHERE 1 = 1 GROUP BY a.id order by id desc LIMIT ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPageBaseJdbcLogger.java 159| ==> Parameters: 5(Integer)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Preparing: SELECT at.`id`, at.`tag_name` FROM `article_to_tag` att LEFT JOIN `article_tag` at ON at.id = att.tag_id LEFT JOIN `article` a ON a.id = att.article_id WHERE a.id = ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Parameters: 8(Long)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| <==== Total: 4
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Preparing: SELECT at.`id`, at.`tag_name` FROM `article_to_tag` att LEFT JOIN `article_tag` at ON at.id = att.tag_id LEFT JOIN `article` a ON a.id = att.article_id WHERE a.id = ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Parameters: 7(Long)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| <==== Total: 2
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Preparing: SELECT at.`id`, at.`tag_name` FROM `article_to_tag` att LEFT JOIN `article_tag` at ON at.id = att.tag_id LEFT JOIN `article` a ON a.id = att.article_id WHERE a.id = ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Parameters: 6(Long)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| <==== Total: 4
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Preparing: SELECT at.`id`, at.`tag_name` FROM `article_to_tag` att LEFT JOIN `article_tag` at ON at.id = att.tag_id LEFT JOIN `article` a ON a.id = att.article_id WHERE a.id = ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Parameters: 5(Long)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| <==== Total: 3
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Preparing: SELECT at.`id`, at.`tag_name` FROM `article_to_tag` att LEFT JOIN `article_tag` at ON at.id = att.tag_id LEFT JOIN `article` a ON a.id = att.article_id WHERE a.id = ?
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| ====> Parameters: 4(Long)
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.d.a.ArticleTagDao.queryTagsByArticleIdBaseJdbcLogger.java 159| <==== Total: 1
2019-11-27 16:00:33 | DEBUG | http-nio-8088-exec-4 | c.l.d.s.dao.article.ArticleDao.queryListPageBaseJdbcLogger.java 159| <== Total: 5
2019-11-27 16:00:33 | INFO | http-nio-8088-exec-4 | c.l.d.springboot.service.impl.ArticleServiceImplArticleServiceImpl.java 46| 查询耗时: 18
2019-11-27 16:00:33 | INFO | http-nio-8088-exec-4 | com.ljq.demo.springboot.web.acpect.LogAspectLogAspect.java 76| [AOP-LOG-END]
<200 OK,ApiResult(code=1000, msg=成功, data=PageInfo{pageNum=1, pageSize=5, size=5, startRow=1, endRow=5, total=8, pages=2, list=Page{count=true, pageNum=1, pageSize=5, startRow=0, endRow=5, total=8, pages=2, reasonable=false, pageSizeZero=false}[ArticleEntity(id=8, title=雨一直下, content=雨一直下，气氛不算融洽, tagList=[ArticleTagEntity(id=3, tagName=高级), ArticleTagEntity(id=6, tagName=springBoot), ArticleTagEntity(id=7, tagName=springMVC), ArticleTagEntity(id=4, tagName=超高级)]), ArticleEntity(id=7, title=小苹果, content=你是我的小丫小苹果，怎么爱你都不嫌多, tagList=[ArticleTagEntity(id=6, tagName=springBoot), ArticleTagEntity(id=1, tagName=初级)]), ArticleEntity(id=6, title=演员, content=简单点，说话的方式简单点。递进的情绪请省略，你又不是个演员, tagList=[ArticleTagEntity(id=4, tagName=超高级), ArticleTagEntity(id=1, tagName=初级), ArticleTagEntity(id=5, tagName=spring), ArticleTagEntity(id=7, tagName=springMVC)]), ArticleEntity(id=5, title=冬日里的一把火, content=你就像那一把火，熊熊火焰燃烧了我, tagList=[ArticleTagEntity(id=1, tagName=初级), ArticleTagEntity(id=2, tagName=中级), ArticleTagEntity(id=3, tagName=高级)]), ArticleEntity(id=4, title=静夜思, content=窗前明月光，疑是地上霜。举头望明月，低头思故乡。, tagList=[ArticleTagEntity(id=7, tagName=springMVC)])], prePage=0, nextPage=2, isFirstPage=true, isLastPage=false, hasPreviousPage=false, hasNextPage=true, navigatePages=8, navigateFirstPage=1, navigateLastPage=2, navigatepageNums=[1, 2]}, extraData=null, timestamp=1574841633357),{Content-Type=[application/json]}>
7 参考文档推荐
官方文档 MyBatis Pagination - PageHelper
官方文档 How to use PageHelper
官方文档 PageHelper integration with Spring Boot
8 Github 源码
Gtihub 源码地址 : https://github.com/Flying9001/springBootDemo
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