1、实现步骤说明:
1.准备数据库创建表
2.添加起步依赖
3.创建POJO
4.创建mapper接口
5.创建映射文件
6.配置yml 指定映射文件位置
7.创建启动类,加入注解扫描
8.创建service controller 进行测试
项目结构图如下:

ps:TestController是我用来做其他操作的与整合无关
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(50) DEFAULT NULL,
`password` varchar(50) DEFAULT NULL,
`name` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;
INSERT INTO `user` VALUES ('1', 'zhangsan', '123', '张三');
INSERT INTO `user` VALUES ('2', 'lisi', '123', '李四');
3、创建工程并添加依赖pom.xml如下参考:
<?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.cyq</groupId>
<artifactId>mybatisspringboot</artifactId>
<version>1.0-SNAPSHOT</version>
<!--添加父工程-->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.0</version>
</parent>
<dependencies>
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<!--加了scope会导致application.yml文件报红,但不影响操作,可加可不加,不加application.yml文件不会报红-->
<scope>runtime</scope>
</dependency>
<!--mybatis-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.1</version>
</dependency>
<!--spring web 起步依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
</project>

4、创建pojo,参考如下:
package com.cyq.pojo;
import java.io.Serializable;
public class User implements Serializable {
private Integer id;
private String username;
private String password;
private String name;
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", name='" + name + '\'' +
'}';
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
5、创建mapper接口,参考如下:
package com.cyq.dao;
import com.cyq.pojo.User;
import java.util.List;
public interface UserMapper {
public List findAllUser();
}
6、创建UserMapper映射文件,如下图所示:

<?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.cyq.dao.UserMapper">
<select id="findAllUser" resultType="com.cyq.pojo.User">
SELECT * from user
</select>
</mapper>
ps:注意namespace的Usermapper和resultType的User类的位置要对应上不然报错
7、创建配置application.yml文件:
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost/user?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
username: root
password: 123456
#配置mapper的映射文件的位置
mybatis:
mapper-locations: classpath:mappers/*Mapper.xml
ps:数据库名记得更改,账号、密码对应
*这里报红但是没关系:

*没加上cj(driver-class-name: com.mysql.cj.jdbc.Driver)会有以下提示:

8、创建启动类,加入mapper接口注解扫描,MybatisApplication文件参考如下:
package com.cyq;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan(basePackages = "com.cyq.dao")
public class MybatisApplication {
public static void main(String[] args) {
SpringApplication.run(MybatisApplication.class);
}
}
9、创建service 实现类和接口:
(1)service:
package com.cyq.service;
import com.cyq.pojo.User;
import java.util.List;
public interface UserService {
public List findAllUser();
}
(2)impl:
package com.cyq.service.impl;
import com.cyq.dao.UserMapper;
import com.cyq.pojo.User;
import com.cyq.service.UserService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Resource
private UserMapper userMapper;
@Override
public List findAllUser() {
return userMapper.findAllUser();
}
}
10、创建controller:
package com.cyq.controller;
import com.cyq.pojo.User;
import com.cyq.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.util.List;
@RestControllerAdvice
@RequestMapping("/user")
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("/findAll")
public List findAll(){
return userService.findAllUser();
}
}
11、测试:
输入网址:

这里用到了一个插件:


链接:https://pan.baidu.com/s/1vwIA4bXvZ8gSBTc_WQqPww
提取码:json
下载好之后:
打开浏览器的设置->扩展程序->打开开发者模式->将下载好的插件拖进去即可



