mybatis-plus多表分页查询最佳实践
- 需求描述：查询指定用户对应的所有订单信息，以订单表为主表关联用户表和订单明细表分页查询用户的订单信息
- 设计思路：使用powerdesigner设置用户表、订单表、订单明细表
- 建表 语句如下所示：
/*==============================================================*/
/* DBMS name: MySQL 5.0 */
/* Created on: 2022/3/17 16:21:35 */
/*==============================================================*/
drop table if exists bus_order;
drop table if exists bus_order_details;
drop table if exists sys_user;
/*==============================================================*/
/* Table: bus_order */
/*==============================================================*/
create table bus_order
(
id int not null auto_increment comment '主键',
order_code varchar(128) comment '订单编号',
user_id int comment '用户id',
primary key (id)
);
/*==============================================================*/
/* Table: bus_order_details */
/*==============================================================*/
create table bus_order_details
(
id int not null auto_increment comment '主键',
product_name varchar(64) comment '商品名称',
product_spec varchar(64) comment '商品规格',
product_price decimal(8,2) comment '商品价格',
order_id int comment '订单编号',
primary key (id)
);
/*==============================================================*/
/* Table: sys_user */
/*==============================================================*/
create table sys_user
(
id int not null auto_increment comment '主键',
user_name varchar(32) comment '用户名',
primary key (id)
);
alter table bus_order add constraint FK_order_reference_user_fk foreign key (user_id)
references sys_user (id) on delete restrict on update restrict;
alter table bus_order_details add constraint FK_order_detail_reference_order_fk foreign key (order_id)
references bus_order (id) on delete restrict on update restrict;
- 新建springboot项目，在pom文件引入所需的依赖
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<groupId>com.yfgroupId>
<artifactId>sp-cloud-alibabaartifactId>
<version>1.0-SNAPSHOTversion>
<relativePath>../../ttys/pom.xmlrelativePath>
parent>
<packaging>jarpackaging>
<modelVersion>4.0.0modelVersion>
<artifactId>content-centerartifactId>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>com.alibaba.cloudgroupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>
dependency>
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-boot-starterartifactId>
dependency>
<dependency>
<groupId>com.baomidougroupId>
<artifactId>mybatis-plus-generatorartifactId>
dependency>
<dependency>
<groupId>org.apache.velocitygroupId>
<artifactId>velocityartifactId>
<version>1.6.3version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
dependency>
dependencies>
<build>
<finalName>${project.artifactId}finalName>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
<executions>
<execution>
<goals>
<goal>repackagegoal>
goals>
execution>
executions>
plugin>
plugins>
build>
project>
- 在项目的主包结构下新建代码生成类MpGenerator
package com.yf.contentcenter.utils;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.*;
import com.baomidou.mybatisplus.generator.config.converts.MySqlTypeConvert;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.DateType;
import com.baomidou.mybatisplus.generator.config.rules.DbColumnType;
import com.baomidou.mybatisplus.generator.config.rules.IColumnType;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.VelocityTemplateEngine;
import java.util.ArrayList;
import java.util.List;
public class MpGenerator {
public static void main(String[] args) throws InterruptedException {
//用来获取Mybatis-Plus.properties文件的配置信息
//final ResourceBundle rb = ResourceBundle.getBundle("mybatisplus");
// 代码生成器
AutoGenerator mpg = new AutoGenerator();
// 全局配置
GlobalConfig gc = new GlobalConfig();
gc.setOutputDir("D:/ttys/server-01/src/main/java"); //修改成自己的项目路径一直到java
gc.setFileOverride(true);//覆盖已有文件
gc.setOpen(false);
gc.setBaseResultMap(true);
gc.setBaseColumnList(true);
gc.setAuthor("yf");
gc.setMapperName("%sMapper");
gc.setXmlName("%sMapper.xml");
gc.setServiceName("%sService");
gc.setServiceImplName("%sServiceImpl");
gc.setControllerName("%sController");
gc.setDateType(DateType.ONLY_DATE);
mpg.setGlobalConfig(gc);
// 数据源配置
DataSourceConfig dsc = new DataSourceConfig();
dsc.setDbType(DbType.MYSQL);
dsc.setUrl("jdbc:mysql://127.0.0.1:3308/yyds?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC");
dsc.setDriverName("com.mysql.cj.jdbc.Driver");
dsc.setUsername("root");
dsc.setPassword("root");
dsc.setTypeConvert(new MySqlTypeConvertCustom());
mpg.setDataSource(dsc);
// 包配置
PackageConfig pc = new PackageConfig();
pc.setParent("com.yf.cn");
//pc.setController("controller");
pc.setService("service");
pc.setServiceImpl("service.impl");
pc.setEntity("entity");
pc.setMapper("mapper");
mpg.setPackageInfo(pc);
// 自定义配置
InjectionConfig cfg = new InjectionConfig() {
@Override
public void initMap() {
// to do nothing
}
};
// 如果模板引擎是 freemarker
//String templatePath = "/templates/mapper.xml.ftl";
// 如果模板 引擎是 velocity
String templatePath = "/templates/mapper.xml.vm";
List<FileOutConfig> focList = new ArrayList<>();
focList.add(new FileOutConfig(templatePath) {
@Override
public String outputFile(TableInfo tableInfo) {
// 自定义输入文件名称
return "D:/ttys/server-01/src/main/resources" + "/mappers/" + tableInfo.getEntityName() + StringPool.DOT_XML;
}
});
cfg.setFileOutConfigList(focList);
mpg.setCfg(cfg);
mpg.setTemplate(new TemplateConfig().setXml(null));
// 策略配置
StrategyConfig strategy = new StrategyConfig();
strategy.setNaming(NamingStrategy.underline_to_camel);
strategy.setColumnNaming(NamingStrategy.underline_to_camel);
strategy.setEntityLombokModel(true);
//建立不包含哪些表
//strategy.setExclude(new String[]{rb.getString("tableName")});
//建立包含哪些表空 为所有表
strategy.setInclude("sys_user","bus_order","bus_order_details");
mpg.setStrategy(strategy);
//mpg.setTemplateEngine(new FreemarkerTemplateEngine());
mpg.setTemplateEngine(new VelocityTemplateEngine());
mpg.execute();
}
}
/**
* 自定义类型转换
*/
class MySqlTypeConvertCustom extends MySqlTypeConvert implements ITypeConvert{
@Override
public IColumnType processTypeConvert(GlobalConfig globalConfig, String fieldType) {
String t = fieldType.toLowerCase();
if (t.contains("tinyint(1)")) {
return DbColumnType.INTEGER;
}
return super.processTypeConvert(globalConfig, fieldType);
}
}
- 在数据库中运行建表语句，创建三张表，然后在代码生成类中配置 数据 库和对应的表 是生成对应的代码
- 在BusOrderMapper中新增查新的接口
Page<OrderDto> getOrderList(@Param("page") Page<OrderDto> page,@Param(Constants.WRAPPER) QueryWrapper<OrderDto> qw);
OrderDto 为最终返回的实体模型，参数中需要定义Page和查询参数QueryWrapper，格式必须按照上面格式来写
- 在BusOrder.xml定定义查询的sql语句
<select id="getOrderList" resultMap="OrderListMapping">
SELECT
bo.id as order_id,
bo.order_code,
bod.product_name,
bod.product_spec,
bod.product_price,
su.user_name
FROM
bus_order bo,
sys_user su,
bus_order_details bod
<where>
bo.user_id = su.id
AND bo.id = bod.order_id and
${ew.sqlSegment}
where>
select>
<select id="getOrderListForJoin" resultMap="OrderListMapping">
SELECT
bo.id AS order_id,
bo.order_code,
bod.product_name,
bod.product_spec,
bod.product_price,
su.user_name
FROM
bus_order bo
LEFT JOIN sys_user su ON bo.user_id = su.id
LEFT JOIN bus_order_details bod ON bo.id = bod.order_id
${ew.customSqlSegment}
select>
<resultMap id="OrderListMapping" type="com.yf.contentcenter.dto.OrderDto">
<id column="order_id" property="id" javaType="int"/>
<result column="order_code" property="orderCode" javaType="String"/>
<result column="product_name" property="productName"/>
<result column="product_spec" property="productSpec" javaType="String"/>
<result column="product_price" property="productPrice" javaType="java.math.BigDecimal"/>
<result column="user_name" property="userName" javaType="String"/>
resultMap>
- 在test目录下新建TestMapper测试类
package com.yf.usercenter;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.yf.usercenter.dto.OrderDto;
import com.yf.usercenter.entity.BusOrder;
import com.yf.usercenter.entity.BusOrderDetails;
import com.yf.usercenter.entity.RunoobTbl;
import com.yf.usercenter.entity.SysUser;
import com.yf.usercenter.mapper.BusOrderDetailsMapper;
import com.yf.usercenter.mapper.BusOrderMapper;
import com.yf.usercenter.mapper.RunoobTblMapper;
import com.yf.usercenter.mapper.SysUserMapper;
import java.math.BigDecimal;
import java.util.Date;
import java.util.List;
import javax.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
/**
* @author yangfeng
* @version 1.0
* @date 2022-03-16 17:53
*/
@SpringBootTest
@RunWith(SpringJUnit4ClassRunner.class)
//@RequiredArgsConstructor(onConstructor = @__(@Autowired))
@Slf4j
public class TestMapper {
//@Autowired
@Resource
private RunoobTblMapper runoobTblMapper;
@Resource
private SysUserMapper sysUserMapper;
@Resource
private BusOrderMapper busOrderMapper;
@Resource
private BusOrderDetailsMapper busOrderDetailsMapper;
@Test
public void testSelectPage(){
Page<OrderDto> page = new Page<OrderDto>(1,3);
QueryWrapper<OrderDto> queryWrapper = new QueryWrapper<OrderDto>();
queryWrapper.eq("bo.user_id",2).like("bod.product_name","吃面");
Page<OrderDto> orderList = busOrderMapper.getOrderList(page, queryWrapper);
System.out.println(orderList.getRecords());
}
@Test
public void testSelectPageForJoin(){
Page<OrderDto> page = new Page<OrderDto>(1,3);
QueryWrapper<OrderDto> queryWrapper = new QueryWrapper<OrderDto>();
queryWrapper.eq("bo.user_id",2).like("bod.product_name","吃面");
Page<OrderDto> orderList = busOrderMapper.getOrderListForJoin(page, queryWrapper);
System.out.println(orderList.getRecords());
}
}
- 执行testSelectPage或者testSelectPageForJoin方法即可实现mybatis-plus多表分页查询
