Mybatis与Springboot的整合

1.导入sprinboot依赖，数据库连接依赖，mybatis依赖，junit依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.10</version>
        <relativePath/> <!-- lookup parent from repository -->
</parent>
<!--Mybatis-->
<dependencies>
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<!--springboot依赖-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
    <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version> 
        </dependency>
         <!--Spring Boot Test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
</dependencies>

2.编写mybatis核心配置文件（yml）

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: 3237never
    url: jdbc:mysql://localhost:3306/greatecommunity
  #配置映射文件位置，相当于在xml中的<package name="com.duhong.dao"/>
  mybatis:
    mapper-locations: classpath:com/duhong/mapper/*.xml

3.配置mapper映射文件,注意namespace 必须指定对应mapper接口的权限定类名，而且映射文件目录结构要与mapper接口一致，映射文件去掉xml的名称与mapper接口名称一致。

<mapper namespace="com.duhong.mapper.UserMapper"> 
        <!--id属性对应的名称要与mappe接口中的方法一致-->
        <select id="selectAll" resultType="com.duhong.entity.User">
            select * from users;
        </select>
</mapper>

4.编写mapper接口

@Mapper
public interface UserMapper {
    int insertUser(User user);
    List<User> selectAll();
}

5.测试

@SpringBootTest
public class Maintest {
    @Autowired
    private UserMapper userMapper;
    @Test
    void testinsertUser(){

        List<User> users = userMapper.selectAll();
        System.out.println(users);
    }
}