這是我的端點 http://localhost:8080/country/all 回覆所有國家都可以

當我想過濾它們時返回未找到 國家為空並回傳異常 throw new RecordNotFoundException("無效請求，無資料回傳"); 在我的資料庫中有一筆記錄 縣_代碼 國家 KM科摩羅

這是我的 json 負載

{
     "country_code":["KM"]
    }

public interface CountryRepo extends JpaRepository<Country, Id>, JpaSpecificationExecutor<Country> {

    }

    public final class CountrySpecs<T> implements Specification<T> {
    
    final private SearchCriteria criteria;
    
    public CountrySpecs(SearchCriteria searchCriteria) {
        this.criteria = searchCriteria;
    }

        @Override
        @Nullable
        public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
        switch (criteria.getOperation()) {
            case ":":
              if (root.get(criteria.getKey()).getJavaType() == String.class) {
                return builder.like(
                        root.<String>get(criteria.getKey()),
                        "%" + criteria.getValue() + "%");
              } else {
                return builder.equal(root.get(criteria.getKey()),
                        criteria.getValue());
              }
            case "=":
              return builder.equal(root.get(criteria.getKey()),
                      criteria.getValue());
            case "in":
              return builder.in(root.get(criteria.getKey())).value(criteria.getValue());
            default:
              return null;
       }
       }
    }

     @GetMapping("/all")
     public ResponseEntity<Map<String, Object>> getAll(
         @Valid @RequestBody Map<String, Object> request) throws Exception {
         List<Country> countries = new ArrayList<>();
 
         int page = (request.get("page") != null) ? (int) request.get("page") : 1;
         int size = (request.get("size") != null) ? (int) request.get("size") : DEFAULT_SIZE;

        // page-1 mi da la possibilità di scrivere nel payload page=1
        Pageable pageable = PageRequest.of(
           page,
          size);
        Page<Country> pageCountries = null;

       /* Validazione */

       /* filter */
       if (request.keySet().size() > 0) {
          CountrySpecs<Country> countrySpecs = null;
          if (request.keySet().contains("country_code")) {
             List<String> list = (List<String>) request.get("country_code");
             /* paginazione filtrata */
             countrySpecs = new CountrySpecs<>(new SearchCriteria("country_code", "in", list));
             pageCountries = repository.findAll(
               countrySpecs,
               pageable);
             countries = pageCountries.getContent();
          }
      } else {
        pageCountries = repository.findAll(pageable);
        countries = pageCountries.getContent();
      }

      if (countries.isEmpty()) {
        // la tabella interrogata non ha dati
        throw new RecordNotFoundException("无效请求，无数据返回");
      }

      Map<String, Object> obj = new TreeMap<>();
      // aggiunta delle informazioni sulla paginazione
      obj.put("countries", countries);
      obj.put("currentPage", pageCountries.getNumber());
      obj.put("totalItems", pageCountries.getTotalElements());
      obj.put("totalPages", pageCountries.getTotalPages());

     ResponseEntity<Map<String, Object>> response = new ResponseEntity<>(
        obj,
        HttpStatus.OK);
       return response;
    }

謝謝Rashin，我已經改進了程式碼，但這個問題仍然存在！ 希望能找到解決方法。

重置程式碼後，它正在工作......