java - 错误: Missing return statement when throwing a new ResponseStatusException in method

Question

当尝试在方法中抛出新异常而不是直接抛出异常时，我的 IDE 会在 catch block 中显示错误“缺少 return 语句”。

REST Controller 的缩小示例:

@RestController
public class RootController {
  protected final Logger log = Logger.getLogger("myLogger");

  @PostMapping(
    value={"sample/",
           "sample/123"},
    consumes = MediaType.APPLICATION_JSON_VALUE,
    produces = MediaType.APPLICATION_JSON_VALUE)
  public @ResponseBody Object getFileContentPost (@RequestBody Request payload) {
    return checkPayloadAndRespond(payload.getFileName());
  }

  private Object checkPayloadAndRespond(String fileName) throws ResponseStatusException {
    if (StringUtils.isEmpty(fileName))
      logErrorAndThrowResponseException(HttpStatus.BAD_REQUEST, "Field fileName is empty or missing!", null);

    try {
      ObjectMapper mapper = new ObjectMapper();
      return mapper.readValue("/static/json/" + fileName , Object.class);
    } catch (IOException e) {
      //line causing ERROR "missing return statement":
      logErrorAndThrowResponseException(HttpStatus.INTERNAL_SERVER_ERROR, "Could not parse file!, e);
    }
  }

  private void logErrorAndThrowResponseException(HttpStatus status, String reason, @Nullable Throwable cause) throws ResponseStatusException {
    log.error("Error occurred: " + reason + ", returning status: " + status);
    throw new ResponseStatusException(status, reason, cause);
  }


}

工作示例:如果我直接使用 throw new 语句而不使用方法:

@RestController
public class RootController {
  protected final Logger log = Logger.getLogger("myLogger");

  @PostMapping(
    value={"sample/",
           "sample/123"},
    consumes = MediaType.APPLICATION_JSON_VALUE,
    produces = MediaType.APPLICATION_JSON_VALUE)
  public @ResponseBody Object getFileContentPost (@RequestBody Request payload) {
    return checkPayloadAndRespond(payload.getFileName());
  }

  private Object checkPayloadAndRespond(String fileName) throws ResponseStatusException {
    if (StringUtils.isEmpty(fileName))
      throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Field fileName is empty or missing!", e);

    try {
      ObjectMapper mapper = new ObjectMapper();
      return mapper.readValue("/static/json/" + fileName , Object.class);
    } catch (IOException e) {
      throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "Could not parse response file!", e);
    }
  }

}

解决这个问题的最佳方法是什么？

我想做的就是在抛出 ResponseStatusException 时实际创建一个日志。

提前致谢。

Answer 1

所以我猜想 void-return-type 导致了这个问题。

我现在通过返回实际响应来解决它，然后抛出:

  private Object checkPayloadAndRespond(String fileName) throws ResponseStatusException {
    if (StringUtils.isEmpty(fileName))
      throw logErrorAndThrowResponseException(HttpStatus.BAD_REQUEST, "Field fileName is empty or missing!", null);

    try {
      ObjectMapper mapper = new ObjectMapper();
      return mapper.readValue("/static/json/" + fileName , Object.class);
    } catch (IOException e) {
throw logErrorAndThrowResponseException(HttpStatus.INTERNAL_SERVER_ERROR, "Could not parse file!, e);
    }
  }

  private ResponseStatusException logErrorAndThrowResponseException(HttpStatus status, String reason, @Nullable Throwable cause) {
    log.error("Error occurred: " + reason + ", returning status: " + status);
    return new ResponseStatusException(status, reason, cause);
  }


}