[java]----Springboot整合Mybatis-优快云博客

以查询学生信息案例为例：

一、在pom.xml中添加依赖


<!--MySQL驱动-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <!--<version>5.1.9</version>-->
</dependency>

<!--MyBatis整合SpringBoot框架的起步依赖-->
<dependency> 
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.0.0</version>
</dependency>

二、配置信息

application.yml

# 配置数据库信息
spring:
  datasource:
    username: root
    password: admin
    # ?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver

# 整合mybatis
mybatis:
# 可以取别名
  type-aliases-package: com.cailearnjava.pojo
# 如果将mapper层的xml配置文件放在resource文件夹下
  mapper-locations: classpath:mybatis/mapper/*.xml

三、mapper层

StudentMapper.java

// 这个注解表示了这是一个 mybatis 的 mapper 类
@Mapper
//此注解表明这是一个持久层组件
@Repository
public interface StudentMapoer {
	
	Student getStudentById(int id);
	
}

配置文件：StudentMapper.xml

<mapper namespace="com.cailearnjava.mapper.UserMapper">
    
    <select id="getStudentById" resultType="Student">
        select * from springboot.student;
    </select>
</mapper>

四、service层

接口文件StudentService.java

public interface StudentService {

    /**
     * 根据学生ID查询详情
     * @param id
     * @return
     */
    Student getStudentById(int id);
}

接口实现类：StudentServiceImpl.java

//此注解表明这是一个服务层组件
@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    @Override
    public Student getStudentById(int id) {
        return studentMapper.getStudentById(id);
    }
}

五、controller层

StudentController.java

//此注解表明这是一个控制层组件
@Controller
public class StudentController {

    @Autowired
    private StudentService studentService;

    @RequestMapping(value = "/student")
    public @ResponseBody Object student(Integer id) {

        Student student = studentService.getStudentById(id);

        return student;
    }
}

六、项目入口文件

//关键注解，开启自动配置
@SpringBootApplication
//开启扫描Mapper接口的包以及子目录
@MapperScan("com.cailearnjava.mapper")
public class Springboot05MybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot05MybatisApplication.class, args);
    }

}

另外，如果mapper的xml配置文件和mapper接口文件放在同一个文件夹下，则要在pom.xml中加入下面代码：

<resources>
    <resource>
        <directory>src/main/java</directory>
        <includes>
            <include>**/*.xml</include>
        </includes>
    </resource>
</resources>