改pom
<dependencies>
<!--mybatis-plus-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
<!--mybatis-plus 代码生成器-->
<dependency>
<groupId>org.apache.velocity</groupId>
<artifactId>velocity-engine-core</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<!-- 项目打包时会将java目录中的*.xml文件也进行打包 -->
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
写yml
mybatis-plus:
mapper-locations: classpath:com/zjazn/smallarea/mapper/xml/*.xml
主启动类，类上追加注解
@MapperScan("com.zjazn.smallarea.mapper")
结构生成器，即entity、mapper、service 、controller
可以直接运行，需要修改数据库连接信息与要生成结构对应的表（查看注释进行修改）
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.rules.DateType;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import org.junit.Test;
/**
* @author
* @since 2018/12/13
*/
public class CodeGenerator {
@Test
public void run() {
// 1、创建代码生成器
AutoGenerator mpg = new AutoGenerator();
// 2、全局配置
GlobalConfig gc = new GlobalConfig();
String projectPath = System.getProperty("user.dir");
//代码生成的绝对路径！！
gc.setOutputDir("/home/nor/code/i/SmallArea/distributed-smallarea-service/product-service/src/main/java/");
gc.setAuthor("testjava");
gc.setOpen(false); //生成后是否打开资源管理器
gc.setFileOverride(false); //重新生成时文件是否覆盖
//UserServie
gc.setServiceName("%sService"); //去掉Service接口的首字母I
gc.setIdType(IdType.ID_WORKER_STR); //主键策略
gc.setDateType(DateType.ONLY_DATE);//定义生成的实体类中日期类型
gc.setSwagger2(true);//开启Swagger2模式
mpg.setGlobalConfig(gc);
// 3、数据源配置 ！！
DataSourceConfig dsc = new DataSourceConfig();
dsc.setUrl("jdbc:mysql://localhost:3306/area_product?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8");
dsc.setDriverName("com.mysql.jdbc.Driver");
dsc.setUsername("root");
dsc.setPassword("3333");
dsc.setDbType(DbType.MYSQL);
mpg.setDataSource(dsc);
// 4、包配置！！！
PackageConfig pc = new PackageConfig();
//包 com.atguigu.eduservice
pc.setParent("com.zjazn");
pc.setModuleName("smallarea"); //模块名
//包 com.atguigu.eduservice.controller
pc.setController("controller");
pc.setEntity("entity");
pc.setService("service");
pc.setMapper("mapper");
mpg.setPackageInfo(pc);
// 5、策略配置
StrategyConfig strategy = new StrategyConfig();
//哪些表要生成！！
strategy.setInclude("goods","goods_detail","goods_type_global","goods_type_local");
strategy.setNaming(NamingStrategy.underline_to_camel);//数据库表映射到实体的命名策略
strategy.setTablePrefix(pc.getModuleName() + "_"); //生成实体时去掉表前缀
strategy.setColumnNaming(NamingStrategy.underline_to_camel);//数据库表字段映射到实体的命名策略
strategy.setEntityLombokModel(true); // lombok 模型 @Accessors(chain = true) setter链式操作
strategy.setRestControllerStyle(true); //restful api风格控制器
strategy.setControllerMappingHyphenStyle(true); //url中驼峰转连字符
mpg.setStrategy(strategy);
// 6、执行
mpg.execute();
}
}
使用mybatis plus强大功能, 基本使用就是注入service层来使用CURD方法，还可以注入Mapper使用CURD方法。
https://baomidou.com/guide/crud-interface.html
条件查询：
LambdaQueryWrapper<User> userWrapper = new LambdaQueryWrapper<>();
//设置等值条件
userWrapper.eq(User::getUsername,username);
//模糊查询
userWrapper.like(User::getUsername,userFo.getUsername());
//追加条件查询
userWrapper.apply("DATE(birth) <= STR_TO_DATE(‘1999-07-21 23:59:59‘,‘%Y-%m-%d %H:%i:%s‘)");
User user = userService.getOne(userWrapper);
（手写）多条件查询，mapper接口：
package com.zjazn.smallarea.mapper;
import com.zjazn.smallarea.entity.Goods;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.zjazn.smallarea.entity.goods;
import org.apache.ibatis.annotations.Param;
import java.util.List;
/**
* <p>
* Mapper 接口
* </p>
*
* @author testjava
* @since 2021-06-22
*/
public interface GoodsMapper extends BaseMapper<Goods> {
List<goods> getGoodsByGlobalTypeId(@Param("id") String id,@Param("start_number") Integer start_number , @Param("item_number") Integer item_number );
}
XML
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.zjazn.smallarea.mapper.GoodsMapper">
<resultMap id="goodsLimit" type="com.zjazn.smallarea.entity.goods">
<id column="id" property="id" jdbcType="VARCHAR"></id>
<result column="store_id" property="store_id" jdbcType="VARCHAR"></result>
<result column="name" property="name" jdbcType="VARCHAR"></result>
<result column="describe" property="describe" jdbcType="VARCHAR"></result>
<result column="price" property="price" jdbcType="DECIMAL"></result>
<result column="cover" property="cover" jdbcType="VARCHAR"></result>
</resultMap>
<select id="getGoodsByGlobalTypeId" resultType="com.zjazn.smallarea.entity.goods" >
SELECT g.id, g.store_id ,gd.name,gd.describe, gd.price, gd.cover FROM goods g
LEFT JOIN goods_detail gd ON g.id = gd.goods_id
WHERE g.partition_global_id=#{id} LIMIT #{start_number},#{item_number};
</select>
</mapper>
注意，XML取值还可以使用 #{0} #{1} ...
很强！Mybatis plus 学习教程 “手写SQL配置” “Mapper多参数传参” + 坑点说明
原文：https://www.cnblogs.com/zjazn/p/14940317.html