springboot整合Mybatis

简单整合mybatis

1、导入依赖，使用JDBC

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

2、连接数据库，编写实体类pojo

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

    private int id;
    private String name;
    private String pwd;
}

3、配置application.yaml

spring:
  datasource:
    username: xiaofan
    password: 123456
    url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver

# 整合Mybatis
mybatis:
  type-aliases-package: com.fan.pojo
  mapper-locations: classpath:mybatis/mapper/*.xml

4、编写mapper接口

@Mapper//注解表示了这是一个mybatis的mapper接口
@Repository
public interface UserMapper {

    List<User> queryUser();
    User queryUserById(int id);
    int addUser(User user);
    int updateUser(User user);
    int deleteUserById(int id);

}

5、编写UserMapper.xml,根据mapper-locations创建文件路径，resources/mybatis/mapper/UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--configuration核心配置文件-->
<mapper namespace="com.fan.mapper.UserMapper">

    <select id="queryUser" resultType="user">
        select * from user
    </select>

    <select id="queryUserById" resultType="user">
        select * from user where id=#{id}
    </select>

</mapper>

6、编写service层，但此处省略，就不写了，直接写controller

@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;

    @RequestMapping("/query")
    public List<User> query(){
        List<User> list = userMapper.queryUser();
        for (User user : list) {
            System.out.println(user);
        }
        return list;
    }
}

7、测试