不，它没有。

为了从URL异步获取数据您应该使用 NSURLRequest 和 NSURLConnection 方法。

In order to get data from URL asynchronously you should use the NSURLRequest and NSURLConnection approach.

您必须实施 NSURLConnectionDelegate 方法：

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
-(void)connectionDidFinishLoading:(NSURLConnection *)connection;
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;