06_SpringBoot_整合Mybatis_掌握

我会带着你远行 2023-09-27 13:33 98阅读 0赞

导入依赖

<dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.3</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.21</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.12</version>
                <scope>provided</scope>
            </dependency>

编写配置文件

appliction.yml中添加如下配置

spring:
      datasource:
        url: jdbc:mysql://127.0.0.1:3306/mydb?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
        driver-class-name: com.mysql.cj.jdbc.Driver
        username: root
        password: root
    mybatis:
      mapper-locations: classpath:mybatis/*.xml
      type-aliases-package: com.msb.pojo

mapper-locations: classpath:mybatis/\*.xml mapper映射文件包扫描  
type-aliases-package 实体类别名包扫描

编写功能代码

1在启动类上添加注解，表示mapper接口所在位置

@SpringBootApplication
    //@MapperScan("com.msb.mapper")
    public class MyApplication {
        public static void main(String[] args) {
            SpringApplication.run(MyApplication.class,args);
        }
    }

2 定义mapper接口

如果不在MyApplication启动类上添加@MapperScan必须在UserMapper接口上添加@Mapper注解。

//@Mapper
    public interface UserMapper {
        List<User> selectAll();
    }

3 定义mapper.xml映射文件  
在resource下新建mybatis文件夹，mapper.xml文件名没有要求了，不需要和接口名完全对应了，是根据namespace去找接口。但是最好还是和接口名字保持一致

![02d6eb1ed373f295dc17e2dba568060a.png][]

4 controller层代码

package com.msb.controller;
    import com.msb.pojo.User;
    import com.msb.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import java.util.List;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    @Controller
    @RequestMapping("/user")
    public class UserController {
        @Autowired
        private UserService userService;
        @RequestMapping("/findAll")
        @ResponseBody
        public List<User> findAll(){
            return userService.findAll();
        }
    }

5 service层代码

package com.msb.service.impl;
    import com.msb.pojo.User;
    import com.msb.mapper.UserMapper;
    import com.msb.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import java.util.List;
    /**
     * @Author: Ma HaiYang
     * @Description: MircoMessage:Mark_7001
     */
    @Service
    public class UserServiceImpl implements UserService {
        @Autowired
        private UserMapper userMapper;
        @Override
        public List<User> findAll() {
            return userMapper.findAll();
        }
    }

6 idea中往往会误报代码错误,如果我们确定代码无问题,可以通过降低idea检查代码的严格程度来消除报错

快捷键: ctrl+alt+shift+h

![d096f1cb8b4d109e5c59666e86566c77.png][]

[02d6eb1ed373f295dc17e2dba568060a.png]: https://img-blog.csdnimg.cn/img_convert/02d6eb1ed373f295dc17e2dba568060a.png
[d096f1cb8b4d109e5c59666e86566c77.png]: https://img-blog.csdnimg.cn/img_convert/d096f1cb8b4d109e5c59666e86566c77.png