一、pom文件添加依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.4</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<build>
    <plugins>
        <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
            <mainClass>com.example.Application</mainClass>
        </configuration>
        <executions>
            <execution>
            <goals>
                <goal>repackage</goal>
            </goals>
            </execution>
        </executions>
        </plugin>
    </plugins>
    <resources>
        <resource>
        <directory>src/main/java</directory>
        <includes>
            <include>**/*.xml</include>
        </includes>
        <filtering>false</filtering>
        </resource>
        <resource>
        <directory>src/main/resources</directory>
        <includes>
            <include>**/*.html</include>
            <include>**/*.css</include>
            <include>**/*.js</include>
            <include>**/*.yml</include>
        </includes>
        <filtering>false</filtering>
        </resource>
    </resources>
</build>

二、修改yml配置文件

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/example?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    driver-class-name: com.mysql.jdbc.Driver
mybatis:
  mapper-locations: classpath:com/example/mapper/*Mapper.xml ## mapper.xml所在目录

三、启动类添加MapperScan注解

在启动类上添加 @MapperScan("com.example.mapper") ，扫面Mapper。

mapper.xml文件的基本结构

<?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.example.mapper.UserMapper">

</mapper>