SpringBoot（四）整合Mybatis

布满荆棘的人生 2024-03-22 10:07 46阅读 0赞

## 整合Mybatis ##

### 一、导入依赖 ###

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>3.0.0</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.27</version>
    </dependency>

### 二、编写yml配置文件 ###

spring:
      # 配置数据源
      datasource:
        url: jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
        driver-class-name: com.mysql.cj.jdbc.Driver
        username: root
        password: 123456
    ##配置mybatis
    mybatis:
      #  mapper映射文件包扫描
      mapper-locations: classpath:/mapper/*.xml
      #  实体类别名包扫描
      type-aliases-package: com.yka.pojo

### 三、在启动类上添加注解，表示mapper接口所在位置 ###

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

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

### 四、定义mapper接口 ###

@Mapper
    public interface TestMapper {
        List<String> selectNameAll();
    }

### 五、定义mapper.xml映射文件 ###

在resource下新建mappers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

<?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.buba.mappers.TestMapper">
        <select id="selectNameAll" resultType="string">
            select name from user
        </select>
    </mapper>

### 六、service层 ###

@Service
    public class TestServiceImpl implements TestService {
        @Autowired
        private TestMapper testMapper;
        @Override
        public List<String> selectNameAll() {
            return testMapper.selectNameAll();
        }
    }

### 七、controller层 ###

@RestController
    @RequestMapping("/test")
    public class TestController {
    
    @Autowired
    private TestService testService;
    
    @GetMapping("/selectNameAll")
    public List<String> selectNameAll() {
        return testService.selectNameAll();
    }
    }