打印HTTP返回头信息

转自：http://lj-1105.blog.163.com/blog/static/109953129201081322237795/

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{
    NSHTTPURLResponse * httpResponse;
    NSString *          contentTypeHeader;
    httpResponse = (NSHTTPURLResponse *) response;
    assert( [httpResponse isKindOfClass:[NSHTTPURLResponse class]] );
    NSDictionary *httpResponseHeaderFields = [httpResponse allHeaderFields];
    NSLog(@"%@",httpResponseHeaderFields);
    nStatusCode = httpResponse.statusCode;
    if (nStatusCode != 200) 
   {
    } 
   else 
   {
        contentTypeHeader = [httpResponse.allHeaderFields objectForKey:@"Content-Type"];
    }    
}