通用mapper就是指的是 tk.mybatis 包下的。这个是通用mapper就是说自动生成的dao层需要继承这个框架提供的mapper类。而我们之前用的org.mybatis这个最开始是普通的。
就是说最开始我们用这个会给我们生成dao接口（不继承其他类），mapper文件（有许多方法增删改查）和实体类。我们感觉很麻烦，所以就出来了通用mapper，只需要继承mapper类就行，自动有增删改查的方法，类似于jpa。代码很简洁。我们这里只讲一下如何自动生成。
坑很多，比如说springboot2.0以上就会出问题，换成1.5就可以。要按照教程来。肯定会成功的。
pom文件
<?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.example</groupId>
<artifactId>tk-mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>tk-mybatis</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.10.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</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-web</artifactId>
</dependency>
<!--mybatis-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- mybatis 逆向生成工具 -->
<dependency>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.3.2</version>
<scope>compile</scope>
<optional>true</optional>
</dependency>
<!--mapper -->
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper-spring-boot-starter</artifactId>
<version>1.2.4</version>
</dependency>
<!--数据库连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</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>
<!--generator配置文件所在位置-->
<configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile>
<verbose>true</verbose>
<overwrite>true</overwrite>
</configuration>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.36</version>
</dependency>
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
<version>3.4.0</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>generatorConfig.properties
# Generator generator.targetProject=src/main/java generator.mappers=com.example.demo.baseMapper.IBaseMapper generator.javaModel-targetPackage=com.example.demo.domain generator.sqlMap-targetPackage=com.example.demo.dao generator.javaClient-targetPackage=com.example.demo.dao #mysql driverClass=com.mysql.jdbc.Driver connectionURL=jdbc:mysql://localhost:3306/video?serverTimezone=UTC userId=root password=root
generatorConfig.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<!--根节点 -->
<generatorConfiguration>
<!-- 指定外部的属性元素 -->
<properties resource="generatorConfig.properties"/>
<!-- 必须 指定生成一组对象的环境 -->
<context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
<!--分隔符 -->
<property name="autoDelimitKeywords" value="true"/>
<property name="beginningDelimiter" value="`"/>
<property name="endingDelimiter" value="`"/>
<!-- 通用mapper插件 -->
<plugin type="tk.mybatis.mapper.generator.MapperPlugin">
<!-- 此处的 MyMapper注意一定不能被扫描到-->
<property name="mappers" value="${generator.mappers}"/>
</plugin>
<!-- 注释 规则-->
<commentGenerator>
<property name="suppressAllComments" value="false"/>
<property name="suppressDate" value="true"/>
</commentGenerator>
<jdbcConnection driverClass="${driverClass}"
connectionURL="${connectionURL}"
userId="${userId}"
password="${password}">
</jdbcConnection>
<javaModelGenerator targetPackage="${generator.javaModel-targetPackage}" targetProject="${generator.targetProject}"/>
<sqlMapGenerator targetPackage="${generator.sqlMap-targetPackage}" targetProject="${generator.targetProject}"/>
<javaClientGenerator targetPackage="${generator.javaClient-targetPackage}" targetProject="${generator.targetProject}"
type="XMLMAPPER"/>
<table tableName="bgm">
<!--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>IBaseMapper（让生成的mapper接口都继承这个类）
package com.example.demo.baseMapper;
import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;
/**
* Created by 敲代码的卡卡罗特
* on 2018/11/1 22:04.
*/
public interface IBaseMapper<T> extends Mapper<T>, MySqlMapper<T> {
}就ok了。