Thingsboard源码分析（一）数据库crud--SpringDataJPA

从CustomerController入手，其getCustomers方法调用了CustoemrService.findCustomersByTenantId方法

• CustomerService是由于CustoemrController继承了baseController。baseController注入了一个CustoemrService（接口）

@PreAuthorize("hasAuthority('TENANT_ADMIN')")
    @RequestMapping(value = "/customers", params = {"pageSize", "page"}, method = RequestMethod.GET)
    @ResponseBody
    public PageData getCustomers(@RequestParam int pageSize,
                                           @RequestParam int page,
                                           @RequestParam(required = false) String textSearch,
                                           @RequestParam(required = false) String sortProperty,
                                           @RequestParam(required = false) String sortOrder) throws ThingsboardException {
        try {
            Pagelink pagelink = createPagelink(pageSize, page, textSearch, sortProperty, sortOrder);
            TenantId tenantId = getCurrentUser().getTenantId();
            return checkNotNull(customerService.findCustomersByTenantId(tenantId, pagelink));
        } catch (Exception e) {
            throw handleException(e);
        }
    }

• 根据SpringBoot自动注入，需要在IOC容器中找到一个CustomerService的实现类。这个类是dao/src/main/java/org/thingsboard/server/dao/customer/CustomerServiceImpl.java 。然后这个类又注入了一个CustomerDao（接口），使用了customerDao.findCustomersByTenantId方法。

@Override
    public PageData findCustomersByTenantId(TenantId tenantId, Pagelink pagelink) {
        log.trace("Executing findCustomersByTenantId, tenantId [{}], pagelink [{}]", tenantId, pagelink);
        Validator.validateId(tenantId, "Incorrect tenantId " + tenantId);
        Validator.validatePagelink(pagelink);
        return customerDao.findCustomersByTenantId(tenantId.getId(), pagelink);
    }

• 然后需要找到CustomerDao的实现类JpaCustomerDao.java。可以看到它又注入了一个CustomerRepository，调用了customerRepository.findByTenantId方法。

public class JpaCustomerDao extends JpaAbstractSearchTextDao implements CustomerDao {

    @Autowired
    private CustomerRepository customerRepository;

    @Override
    public PageData findCustomersByTenantId(UUID tenantId, Pagelink pagelink) {
        return DaoUtil.toPageData(customerRepository.findByTenantId(
                tenantId,
                Objects.toString(pagelink.getTextSearch(), ""),
                DaoUtil.toPageable(pagelink)));
    }
}

• 然后又发现CustomerRepository接口又继承了PagingAndSortingRepository接口

import org.springframework.data.repository.PagingAndSortingRepository;

public interface CustomerRepository extends PagingAndSortingRepository {

    @Query("SELECt c FROM CustomerEntity c WHERe c.tenantId = :tenantId " +
            "AND LOWER(c.searchText) LIKE LOWER(CONCAt(:textSearch, '%'))")
    Page findByTenantId(@Param("tenantId") UUID tenantId,
                                        @Param("textSearch") String textSearch,
                                        Pageable pageable);

    CustomerEntity findByTenantIdAndTitle(UUID tenantId, String title);

    Long countByTenantId(UUID tenantId);
}

• 重点来了： PagingAndSortingRepository接口是JPA框架提供的一个接口，位于org.springframework.data.repository.PagingAndSortingRepository，继承了这个接口的接口，可以根据方法名自动生成sql语句从而进行查询。比如，User findUserById（int id）方法就会自动生成sql：SELECt * from User where id=#{id}，并根据User的构造方法返回一个User对象
• 数据源配置：application/src/main/resources/thingsboard.yml 配置文件中441~457行

# SQL DAO Configuration
spring:
  data:
    jpa:
      repositories:
        enabled: "true"
  jpa:
    open-in-view: "false"
    hibernate:
      ddl-auto: "none"
    database-platform: "${SPRING_JPA_DATAbase_PLATFORM:org.hibernate.dialect.PostgreSQLDialect}"
  datasource:
    driverClassName: "${SPRING_DRIVER_CLASS_NAME:org.postgresql.Driver}"
    url: "${SPRING_DATASOURCE_URL:jdbc:postgresql://localhost:5432/thingsboard}"
    username: "${SPRING_DATASOURCE_USERNAME:postgres}"
    password: "${SPRING_DATASOURCE_PASSWORD:postgres}"
    hikari:
      maximumPoolSize: "${SPRING_DATASOURCE_MAXIMUM_POOL_SIZE:16}"