Spring cloud 引入MyBatis-Plus

偏执的太偏执、 2022-10-26 12:50 160阅读 0赞

MyBatis-Plus是一个MyBatis的增强工具，在MyBatis的基础上只做增强不做改变，为简化开发、提高效率而生。

## 一、引入MyBatis-Plus依赖 ##

在build.gradle文件中的dependencies的对象中引入依赖  
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implementation 'com.baomidou:mybatis-plus-boot-starter:3.4.2'

引入MyBatis-Plus之后请不要再次引入MyBatis以及MyBatis-Spring，以避免因版本差异导致的问题。

## 二、application.xml配置mybatis-plus ##

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mybatis-plus:
      # mybatis的sql xml映射文件，配置在resources文件夹下
      mapper-locations: classpath:mybatis/*Mapper.xml
      # 数据库表字段实体
      typeAliasesPackage: com.pd.shop.model.entity

## 三、配置Application的mapper扫描路径 ##

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@SpringBootApplication
    @MapperScan(basePackages = "com.pd.shop.mapper")
    public class ShopApplication { 
        public static void main(String[] args) { 
            SpringApplication.run(ShopApplication.class, args);
        }
    }

## 四、封装基类MyBatis-Plus ##

建议一下封装基类,后续进行扩展方便，当然也可以不封装  
对于继承的BaseMapper接口、IService接口、继承ServiceImpl实现类

(1) 继承MyBatis-Plus的BaseMapper  
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package com.pd.shop.mapper;
    
    import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    
    public interface IShopMapper<T> extends BaseMapper<T> { 
    
    }

(2) 继承MyBatis-Plus的IService  
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package com.pd.shop.service;
    
    import com.baomidou.mybatisplus.extension.service.IService;
    
    public interface IShopService<T> extends IService<T> { 
    
    }

(3) 继承MyBatis-Plus的ServiceImpl<M, T>  
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package com.pd.shop.service.impl;
    
    import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
    import com.pd.shop.mapper.IShopMapper;
    import com.pd.shop.service.IShopService;
    
    public class ShopImpl<M extends IShopMapper<T>, T> extends ServiceImpl<M, T> implements IShopService<T> { 
        
    }

## 五、新建实体类 ##

对应步骤二中, mybatis-plus.typeAliasesPackage配置  
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package com.pd.shop.model.entity;
    
    import com.baomidou.mybatisplus.annotation.TableName;
    import lombok.Data;
    
    @Data
    @TableName("user_info")
    public class UserInfo { 
    
        private static final long serialVersionUID = 1L;
    
        private Long id;
    
        /** * 用户昵称 */
        private String nickname;
    
    
        /** * 1男 0女 -1未知 */
        private Integer sex;
    }

## 六、新建mybatis的sql xml映射文件 ##

新建UserInfoMapper.xml resources/mybatis文件夹下，对应步骤二中, mybatis-plus.mapper-locations 配置  
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<?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.pd.shop.mapper.UserInfoMapper">
    
        <select id="queryList" resultType="com.pd.shop.model.entity.UserInfo">
            SELECT
            id,
            nickname,
            sex
            FROM
            user_info
        </select>
    </mapper>

***推荐MybatisX快速开发插件。可以进行跳转，提示等辅助开发功能***

## 七、继承基类 ##

(1) Mapper继承新的IShopMapper,  
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package com.pd.shop.mapper;
    
    import com.pd.shop.model.entity.UserInfo;
    
    import java.util.List;
    
    public interface UserInfoMapper extends IShopMapper<UserInfo> { 
    
        List<UserInfo> queryList();
    }

(2) Service继承新的IShopService,  
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package com.pd.shop.service;
    
    import com.pd.shop.model.entity.UserInfo;
    
    import java.util.List;
    
    public interface UserInfoService extends IShopService<UserInfo> { 
    
        List<UserInfo> queryList();
    }

(3) Impl继承新的ShopImpl  
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package com.pd.shop.service.impl;
    
    import com.pd.shop.mapper.UserInfoMapper;
    import com.pd.shop.model.entity.UserInfo;
    import com.pd.shop.service.UserInfoService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    @Service
    public class UserInfoImpl extends ShopServiceImpl<UserInfoMapper, UserInfo> implements UserInfoService { 
    
        @Override
        public List<UserInfo> queryList(){ 
            UserInfo userInfo= baseMapper.selectById("1336601236750163969");
            //.... baseMapper.
            //.... this.
            //.... 可以调用MyBatis-Plus的方法
            return baseMapper.queryList();
        }
    }

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