[NSURLConnectionsendAsynchronousRequest:requestqueue:[[NSOperationQueuealloc]init]completionHandler:^(NSURLResponse*_Nullableresponse,NSData*_Nullabledata,NSError*_NullableconnectionError) {

//出错则返回

if(connectionError !=nil) {

NSLog(@"connectionError = %@",connectionError);

return;

}else{

//通过NSURLResponse类来获取文件的类型

NSLog(@"%@",response.MIMEType);//获取文件的类型如：text/plain

NSLog(@"%@",response.suggestedFilename);//获取文件名加后缀如：LOG_20170115100747.txt

}