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
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<?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>
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三、编辑application.yml
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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
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四、逆向生成pojo，mapper
创建generatorconfig.xml
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<?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>
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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
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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();
}
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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;
}
}
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创建controller
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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;
}
}
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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springboot+springmvc+mybatis项目整合
运行springbootmybatisplusapplication主函数
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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);
}
}
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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这里学习
（源码下载地址）
最后谢谢大家的观看，写博客经验不足，写得不好请见谅
原文链接：https://www.cnblogs.com/caichaoqi/archive/2018/04/01/8662614.html