SpringBoot +mybatis

新建一个springboot项目

打开New Project > 选择Spring initializr 然后next

导入依赖

  <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>

编写 application.properties

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

新建一个pojo包

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private int id;
    private String name;
    private String pwd;
}

新建一个mapper包

新建一个UserMapper接口
实现增删改查

//这个注解表示了这是一个mybatis的mapper类； dao

@Mapper
@Repository
public interface UserMapper {
      
    List<User> queryUserList();

    User queryUserById(int id);

    int addUser(User user);

    int updateUser(User user);

    int deleteUser(int id);
}

在resources目录下编写mapper

resources -> mybatis -> mapper -> UserMapper.xml
待会会写怎么使用别名 和 UserMapper.xml怎么被spring识别到

<?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.rzk.mapper.UserMapper">
    <select id="queryUserList" resultType="User">
        select * from user
    </select>

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

    <insert id="addUser" parameterType="User">
        insert into user(id,name,pwd) values(#{id},#{name},#{pwd})
    </insert>

    <update id="updateUser" parameterType="User">
        update user set name=#{name},pwd=#{pwd} where id=#{id}
    </update>

    <delete id="deleteUser" parameterType="int">
        delete from user where id=#{id}
    </delete>
</mapper>

别名和识别.xml

在application.properties写

mybatis.type-aliases-package=com.rzk.pojo 别名
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml 扫描mapper包下的.xml文件

测试