hibernate - 非唯一结果异常 : JPARepository Spring boot

Question

我将 SpringBoot 与 JPA 和 QueryDSL 一起使用。我已经编写了一个 HQL 来从表中获取一些自定义记录，但它抛出了 Exception。下面我提到存储库的代码:

@Repository
public interface LoanOfferRepository extends JpaRepository<LoanOffer, Long>, QuerydslPredicateExecutor<LoanOffer> {

    @Query("select lo.startDate,count(*) from LoanOffer lo where lo.loan.fsp= :fsp and lo.startDate between :fromDate and :toDate Group by lo.startDate")
    public Map<LocalDate,Integer> getLastMonthLoans(@Param("fsp")Fsp fsp,@Param("fromDate")LocalDate fromDate,@Param("toDate")LocalDate toDate);
}

每当我调用此方法时 getLastMonthLoans() 我都会遇到以下异常:

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.IncorrectResultSizeDataAccessException: query did not return a unique result: 9; nested exception is javax.persistence.NonUniqueResultException: query did not return a unique result: 9] with root cause

javax.persistence.NonUniqueResultException: query did not return a unique result: 9

代码或查询或返回类型有什么问题吗？查询似乎工作正常。

Answer 1

您的查询结果无法映射到Map<LocalDate,Integer> .

您可以尝试返回 List<Object[]>而不是 Map .

@Query("select lo.startDate,count(*) from LoanOffer lo where lo.loan.fsp= :fsp and lo.startDate between :fromDate and :toDate Group by lo.startDate")
public List<Object[]> getLastMonthLoans(@Param("fsp")Fsp fsp,@Param("fromDate")LocalDate fromDate,@Param("toDate")LocalDate toDate);

然后解析List<Object[]>到Map你需要。

这样:

Map<LocalDate, Integer> mappedResult = new HashMap<>();
List<Object[]> queryResult = loanOfferRepository.getLastMonthLoans(fsp, fromDate, toDate);
for (Object[] obj : queryResult ) {
    LocalDate ld = (LocalDate) obj[0];
    Integer count = (Integer) obj[1];
    mappedResult.put(ld, count);
}