java - ResponseEntity 在使用 DeferredResult 时得到空体

Question

我正在使用 SpringBoot 1.4.4 创建异步 RESTful api。一切正常，除非请求被成功处理，DeferredResult > 总是有空主体和 200 OK 状态代码，即使我明确地将字符串值设置为结果对象。代码如下所示:

RestController 实现:

 @Async
  public DeferredResult<ResponseEntity<String>> parseWithLongDelay(    
     @RequestBody MyRequestObject req){
     DeferredResult<ResponseEntity<String>> result = new DeferredResult<>();
     :
     :
     result.setResult(new ResponseEntity<String>("That big zip file successfully parsed.", HttpStatus.OK));
     return result;
  }

客户端:

 @Test
 public void test(){
    ListenableFuture<ResponseEntity<String>> futureEntity = new AsyncRestTemplate().postForEntity(url, requestEntity,
    String.class);
    futureEntity.addCallback(new MyFutureCallback());
    :
  }
  class MyFutureCallback implements ListenableFutureCallback<ResponseEntity<String>> {
  @Override
  public void onSuccess(ResponseEntity<String> entity) {
   String body = entity.getBody();
   log.info("response content: " + body);
   //always get null body, there is no server side exception or error
   //when callback happens
 }
}  

我期待的是字符串“成功解析了那个大的 zip 文件。”因为 body 得到返回而不是 null？有什么线索吗？请帮忙!

Answer 1

我发现在我的案例中，ShallowEtagHeaderFilter 导致了错误。这是我在休息方法中为避免空体所做的:

ShallowEtagHeaderFilter.disableContentCaching(request);