问iOS无法在移动数据/4G网络上将图像上传到服务器，而在Wifi中，它工作得很好

EN

NSMutableURLRequest * request = [[NSMutableURLRequest alloc] init];
NSString *boundary = @"---------------------------14737809831466499882746641449";
[request setCachePolicy:cachePolicy];
[self prepareMethod:methodURL methodType:methodType dataInBody:dataInBody contentType:contentType withRequest:request];
[request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary] forHTTPHeaderField:@"Content-Type"];


NSMutableData * bodyData = [[NSMutableData alloc] init];

params = [[[NSUserDefaults standardUserDefaults]objectForKey:@"userparams"]mutableCopy];

for (NSString *param in params)
{
    if (![param isEqualToString:@"file"]) {
        [bodyData appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [bodyData appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", param] dataUsingEncoding:NSUTF8StringEncoding]];
        [bodyData appendData:[[NSString stringWithFormat:@"%@\r\n", [params objectForKey:param]] dataUsingEncoding:NSUTF8StringEncoding]];
    }
}

// add image data
[bodyData appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"image.jpeg\"\r\n", @"file"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[@"Content-Type: image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[params objectForKey:@"file"]];
[bodyData appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[bodyData appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];


//NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
// sessionConfiguration.timeoutIntervalForRequest = 120.0;
NSURLSession *session = [NSURLSession sharedSession];

NSURLSessionUploadTask* uploadtask = [session uploadTaskWithRequest:request fromData:bodyData completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){

  if (!error)
  {
      NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)response;
      HttpResponse * response = [[HttpResponse alloc] initWithHttpURLResponse:httpResponse withData:data];

      dispatch_async(dispatch_get_main_queue(), ^{
          if ([delegate respondsToSelector:@selector(connectionFinishedLoading:)]) {
              [delegate connectionFinishedLoading:response];
          }
      });

  }
  else
  {
      dispatch_async(dispatch_get_main_queue(), ^{
          if ([delegate respondsToSelector:@selector(connectionFailedWithError:)])
          {
              [delegate connectionFailedWithError:error];
          }
      });
  }


}];
[uploadtask resume];