介绍：
Mybatis-Plus（简称MP）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。（摘自mybatis-plus官网）Mybatis虽然已经给我们提供了很大的方便，但它还是有不足之处，MP的存在就是为了稍稍弥补Mybatis的不足。在我们使用Mybatis时会发现，每当要写一个业务逻辑的时候都要在DAO层写一个方法，再对应一个SQL，即使是简单的条件查询、即使仅仅改变了一个条件都要在DAO层新增一个方法，针对这个问题，MP这样一个框架，一种集Mybatis与Hibernate的优点一起的框架。它提供了Hibernate的单表CURD操作的方便同时，又保留了Mybatis的特性。
本章只教大家怎么使用MybatisPlus，如果想深入了解底层是怎么实现的可以去官网下载源代码进行解读。
一、创建项目
这里就不一步一步来了，我直接给出创建后的项目结构，在本章的最后我会给出源码地址需要看效果的可以进行下载。
二、引入依赖
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.chaoqi</groupId>
<artifactId>springboot_mybatisplus</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springboot_mybatisplus</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--添加jsp依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
</dependency>
<!-- SpringBoot - MyBatis 逆向工程 -->
<dependency>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.3.2</version>
</dependency>
<!-- MyBatis 通用 Mapper -->
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper-spring-boot-starter</artifactId>
<version>1.1.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-maven-plugin</artifactId>
<version>1.3.2</version>
<configuration>
<configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
<verbose>true</verbose>
<overwrite>true</overwrite>
</configuration>
<executions>
<execution>
<id>Generate MyBatis Artifacts</id>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
<version>3.5.0</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>
三、编辑application.yml
server:
port: 8080
spring:
mvc:
view:
prefix: /WEB-INF/jsp/
suffix: .jsp
datasource:
url: jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8&useUnicode=true&useSSL=false
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
mybatis:
mapper-locations: classpath:mapper/*.xml
type-aliases-package: com.chaoqi.springboot_mybatisplus.domain
四、逆向生成pojo，mapper
创建generatorConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<properties resource="application.yml"/>
<classPathEntry location="D:/mysql/mysql-connector-java-5.1.46/mysql-connector-java-5.1.46.jar"/>
<context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
<property name="beginningDelimiter" value="`"/>
<property name="endingDelimiter" value="`"/>
<property name="javaFileEncoding" value="UTF-8"/>
<plugin type="tk.mybatis.mapper.generator.MapperPlugin">
<property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
</plugin>
<!-- 注释 -->
<commentGenerator>
<!-- 是否生成注释代时间戳 -->
<property name="suppressDate" value="true"/>
<!-- 是否去除自动生成的注释 true：是 ： false:否 -->
<property name="suppressAllComments" value="false"/>
</commentGenerator>
<!-- JDBC连接 -->
<jdbcConnection
driverClass="com.mysql.jdbc.Driver"
connectionURL="jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8"
userId="root"
password="123456">
</jdbcConnection>
<!-- 生成实体类地址 -->
<javaModelGenerator targetPackage="com.chaoqi.springboot_mybatisplus.dao.domain" targetProject="src/main/java"/>
<!-- 生成mapper xml文件 -->
<sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources"/>
<!-- 生成mapper xml对应Client-->
<javaClientGenerator targetPackage="com.chaoqi.springboot_mybatisplus.dao.mapper" targetProject="src/main/java"
type="XMLMAPPER"/>
<!-- 配置表信息 -->
<table tableName="%">
<!--mysql 配置-->
<generatedKey column="id" sqlStatement="Mysql"/>
<!--oracle 配置-->
<!--<generatedKey column="id" sqlStatement="select SEQ_{1}.nextval from dual" identity="false" type="pre"/>-->
</table>
</context>
</generatorConfiguration>
maven运行generator
生成完后的项目结构如下
五、整合mybatisplus
创建service接口以及service实现类
package com.chaoqi.springboot_mybatisplus.service;
import com.chaoqi.springboot_mybatisplus.dao.domain.MusicInfo;
import java.util.List;
public interface MusicInfoService {
public List<MusicInfo> getMusicInfo();
}
package com.chaoqi.springboot_mybatisplus.service.impl;
import com.chaoqi.springboot_mybatisplus.dao.domain.MusicInfo;
import com.chaoqi.springboot_mybatisplus.dao.mapper.MusicInfoMapper;
import com.chaoqi.springboot_mybatisplus.service.MusicInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class MusicInfoServiceImpl implements MusicInfoService {
@Autowired
private MusicInfoMapper musicInfoMapper;
@Override
public List<MusicInfo> getMusicInfo() {
List<MusicInfo> musicInfos = musicInfoMapper.selectAll();
return musicInfos;
}
}
创建Controller
package com.chaoqi.springboot_mybatisplus.web;
import com.chaoqi.springboot_mybatisplus.dao.domain.MusicInfo;
import com.chaoqi.springboot_mybatisplus.service.MusicInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequestMapping(value = "/music")
public class MusicInfoController {
@Autowired
private MusicInfoService musicInfoService;
@RequestMapping("/showMusic")
public List<MusicInfo> getMusicInfo() {
List<MusicInfo> musicInfo1 = musicInfoService.getMusicInfo();
return musicInfo1;
}
}
这里我的mapper并不要写sql，一些简单的sqlmybatiplus都给封装好了，节省了许多开发时间，如果是一些复杂的sql，也可以通过写原生sql来实现，在我的第二篇博客中有讲到http://www.cnblogs.com/caichaoqi/p/8580521.html
运行SpringbootMybatisplusApplication主函数
package com.chaoqi.springboot_mybatisplus;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.chaoqi.springboot_mybatisplus.dao.mapper")
public class SpringbootMybatisplusApplication {
public static void main(String[] args) {
SpringApplication.run(SpringbootMybatisplusApplication.class, args);
}
}
查看数据库
下面给出mybatisplus封装的一些方法，这些方法具体怎么使用，感兴趣的小伙伴可以查看下源代码，mybatisplus还有一个强大的分页功能，如果有兴趣也可以去学习http://mp.baomidou.com
（源码下载地址：https://github.com/caicahoqi/ChaoqiIsPrivateLibrary）
最后谢谢大家的观看，写博客经验不足，写得不好请见谅，如果能给你带来帮助请点个赞，若遇到不明白的，或者有写错的地方可以在下方留言，博主看到后第一时间会给予回复，谢谢。
