java - Json 返回 3 个对象，而不是 java 中的一个？

Question

我有一个 REST 端点，我调用它来请求一些数据，但它在 JSON 响应中返回同一对象三次，而不是只返回不同的结果。

这是我得到的回复:

[
    {
        "id": "5555 ",
        "label": "MAIN USER (5555)  "
    },
    {
        "id": "5555 ",
        "label": "MAIN USER (5555)  "
    },
   {
        "id": "5555 ",
        "label": "MAIN USER (5555)  "
    }
]

这是用于生成 JSON 响应的 Controller :

@RestController
public class AutoCompleteController {
    private AutoCompleteService autoCompleteService;
    private EntityManager em;

    public AutoCompleteController(AutoCompleteService autoCompleteService, EntityManager em) {
        this.autoCompleteService = autoCompleteService;
        this.em = em;
    }

    @RequestMapping(value = "jobs", method = RequestMethod.GET)
    public @ResponseBody
    List<AutoComplete> getSalary(@RequestParam(value = "autocomplete") String autocompleteValue) {
      return autoCompleteService.retrieveSalary(autocompleteValue);
   }
} 

Controller 依次调用AutoCompleteService:

@Service
public class AutoCompleteService {
    private AutoCompleteRepository autocompleteRepository;

    public AutoCompleteService(AutoCompleteRepository autRepo) {
        this.autocompleteRepository = autRepo;
    }

    public List<AutoComplete> retrieveSalary(String jobClassCd) {
        List<AutoComplete>  salaries = autocompleteRepository.findAllByJobClassCdIsContaining(jobClassCd);
        if (salaries.size() <= 0) {
            throw new AutoCompleteNotFoundException(jobClassCd);
        }
        return salaries;
    }
}

Answer 1

只需确保您的方法 autoCompleteService.retrieveSalary 仅返回 1 个结果，根据您的过滤器检查您的数据库是否存在具有相同内容的多行。如果你总是想要 1 个结果，那么让你的返回一个对象，而不是 List<>。