一、前置条件

先创建好一个最简单的spring boot项目，可参考之前章节的源代码或直接自己创建一个。

二、创建数据库

创建数据库

create database springboot;

创建用户表tbl_user并插入测试数据

CREATE TABLE `tbl_user` (`user_id` bigint(20) NOT NULL,`user_name` varchar(50) DEFAULT NULL,`user_age` int(11) DEFAULT NULL,PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;INSERT INTO `tbl_user` VALUES (1, '张三', 27);
INSERT INTO `tbl_user` VALUES (2, '李四', 30);
INSERT INTO `tbl_user` VALUES (3, '王五', 20);

脚本sql在源码的db文件夹中。

三、引入mybatis依赖

<!-- mybatis -->
<dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.3.2</version>
</dependency><!-- mysql -->
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId>
</dependency>

四、编写代码

1、创建实体

package com.songguoliang.mybatis.entity;/*** @Description* @Author sgl* @Date 2018-05-02 14:59*/
public class User {private Long userId;private String userName;private Integer userAge;public Long getUserId() {return userId;}public void setUserId(Long userId) {this.userId = userId;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public Integer getUserAge() {return userAge;}public void setUserAge(Integer userAge) {this.userAge = userAge;}
}

2、创建Mapper文件

在resources文件夹下创建mapper文件夹，然后在mapper文件夹里创建UserMapper.xml，内容如下：

<?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.songguoliang.mybatis.mapper.UserMapper"><select id="getUsers" resultType="User">SELECT * FROM tbl_user</select></mapper>

3、创建Mapper(Dao)接口

package com.songguoliang.mybatis.mapper;import com.songguoliang.mybatis.entity.User;import java.util.List;/*** @Description* @Author sgl* @Date 2018-05-02 15:02*/
public interface UserMapper {List<User> getUsers();
}

4、创建Service

package com.songguoliang.mybatis.service;import com.songguoliang.mybatis.entity.User;
import com.songguoliang.mybatis.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;/*** @Description* @Author sgl* @Date 2018-05-02 15:01*/
@Service
public class UserService {@Autowiredprivate UserMapper userMapper;public List<User> getUsers() {return userMapper.getUsers();}
}

5、创建controller

package com.songguoliang.mybatis.controller;import com.songguoliang.mybatis.entity.User;
import com.songguoliang.mybatis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;/*** @Description* @Author sgl* @Date 2018-05-02 14:59*/
@RestController
public class UserController {@Autowiredprivate UserService userService;@GetMapping("/users")public List<User> lists() {return userService.getUsers();}}

五、配置mybatis

1、配置数据源

在application.properties配置文件中添加如下代码：

## 数据源配置
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

2、添加mybatis配置

在application.properties配置文件中添加mybatis的配置，如下代码：

# mybatis
mybatis.type-aliases-package=com.songguoliang.mybatis.entity
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.configuration.map-underscore-to-camel-case=true

• mybatis.type-aliases-package：别名类(实体类)所在包
• mybatis.mapper-locations：mapper文件所在文件夹
• mybatis.configuration.map-underscore-to-camel-case：采用驼峰命名方式转换

3、扫描Mapper接口

在启动类上添加注解@MapperScan("com.songguoliang.mybatis.mapper") ，注意MapperScan的包路径(org.mybatis.spring.annotation.MapperScan)，后面章节和Mapper4集成时会修改导入的包。

package com.songguoliang.mybatis;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;/*** @Description* @Author sgl* @Date 2018-05-02 14:51*/
@SpringBootApplication
@MapperScan("com.songguoliang.mybatis.mapper")
public class MybatisApplication {public static void main(String[] args) {SpringApplication.run(MybatisApplication.class, args);}
}

六、测试

启动服务，浏览器输入http://localhost:8080/users ,可看到如下内容：