SpringBoot集成MybatisPlus及分析

1引入pom依賴

    <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <!-- 模板引擎 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <!-- 熱部署、測試 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
    <!-- 驅動、連接池 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql-connector-java.version}</version>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid-spring-boot-starter</artifactId>
      <version>${alibaba.druid}</version>
    </dependency>

    <!-- MP -->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
    </dependency>
    <dependency>
      <groupId>com.baomidou</groupId>
      <artifactId>mybatis-plus-boot-starter</artifactId>
      <version>3.1.1</version>
    </dependency>

2 配置連接池

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://192.168.20.40:3306/ca_ct_business?useUnicode=true&characterEncoding=utf8&useSSL=false
    username: root
    password: 123456

3編寫Mapper(繼承BaseMapper即可獲得基礎CRUD操作)

public interface BusinessMapper extends BaseMapper<BusinessEntity> {
}

4使用註解進行Mapper掃描

@MapperScan("com.ca.ct.console.mapper")

5依賴注入使用即可

@RunWith(SpringRunner.class)
@SpringBootTest(classes = Application.class)
public class BaseTest {

    @Autowired
    private BusinessMapper busiMapper;

    @Test
    public void testBusiMapper() {
        System.out.println(busiMapper.selectById(1));
    }
}

6可使用MP中的擴展類ServiceImpl(ServiceImpl中具體還是使用的BaseMapper)

@Service
public class BusinessService extends ServiceImpl<BusinessMapper, BusinessEntity> {
}

    @Autowired
    private BusinessService busiService;

    @Test
    public void testBusiMapper() {
        BusinessEntity oneById = busiService.getOne(new QueryWrapper<BusinessEntity>().eq("ID", 1));
        System.out.println(oneById);
    }

7擴展類IService和BaseMapper區別
①BaseMapper是通用CRUD的簡單封裝，爲Mybatis-Plus在啓動時自動解析實體表關係映射轉換爲Mybatis內部對象注入容器。其功能有限，諸如批量新增等查用接口需自己再封裝。

②擴展類IService是BaseMapper的增強，提供了諸如BaseMapper沒有的批插入、保存或新增、批量更新等，且包含了大量Java1.8支持的默認實現。企業場景使用時，可在Mapper基礎上封裝Dao類，使Dao類繼承IService的實現類ServiceImpl實現功能增強。這裏IService中Service單詞不等於項目中Service服務層單詞中的Service。