JAVA JPA SPRING - IncorrectResultSizeDataAccessException：查询未返回唯一结果：2

Question

@Query(value = "SELECT i.productNumber FROM Product as i ORDER BY i.productNumber DESC") public String getLastProductNumber(); // 这是我的查询，

// 这是我的生成器，我想每次发布产品时都生成加 1，

private String setProductNumber() {
    try {
        String value = productRepository.getLastProductNumber();
        System.out.println("Get Last OrderNumber: " + value);

        long currentValue = 0;
        if (!(value == null || value.isEmpty())) {
            currentValue = Long.parseLong(value);
        }

        String result = String.format("%08d", currentValue + 1);

        return result;
    } catch (EmptyResultDataAccessException e) {
        String result = "00000001";
        return result;

但它在获取 2 个产品编号后导致错误。

Answer 1

嗨，请检查这个例子

  @Query(value = "SELECT i.productNumber FROM Product as i ORDER BY i.productNumber 
  DESC") 
  public List<String> getLastProductNumber();