获取错误消息java.lang.IllegalStateException：getWriter（）已被调用！在返回ResponseEntity <>时

Question

返回时返回新的ResponseEntity <>（jsonObject，HttpStatus.BAD_REQUEST）;在下面的代码中，我在其中打印以下行：LOG.trace（“提供了无效的客户端”）;在其他部分

@Action("VALIDATE")
@RequestMapping(value = "/validate", method = RequestMethod.POST)
public ResponseEntity<JSONObject> valCode(HttpServletRequest request, String userId, String code,
        HttpServletResponse response) throws IOException, TokenIssuerException {

    JSONObject jsonObject = new JSONObject();

    if (code != null) {

        ICode cacheCode = tokenCache.getCode(code, null);

        IClientInfo clientInfo = clientAuthCore.getClient(request, response, true);

        boolean checkClientId = checkClientID(clientInfo, cacheCode);
        if (checkClientId) {

//业务逻辑

        } else {
            LOG.trace("Invalid Client provided");
            return new ResponseEntity<>(jsonObject, HttpStatus.BAD_REQUEST);
        }
    } else {
        LOG.trace("Invalid parameters");
        return new ResponseEntity<>(jsonObject, HttpStatus.BAD_REQUEST);
    }

}

Answer 1

我将返回null，而不是另一个JSON对象，因为已调用getwrite，因此它是解决方案。