NSString *urlString = [NSStringstringWithFormat:@"xxxxxxxxxx"];//xxxx处写一个你的网址

    //如果网址中有中文，需要转换

    urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    //构建NSURL

   NSURL *url = [NSURLURLWithString:urlString];

    //构建请求，这个构建方法是基本构建方法的一个封装加强。主要多了超时属性，就是最后一个参数，4.0f。意思就是如果在4秒内没有响应，就不阻塞主线程（为啥放主线程就不赘述了）

    NSURLRequest *request = [NSURLRequestrequestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicytimeoutInterval:4.0f];

    //以AF开始的是就是AFNetworking框架的API，这是1.x的方法。

   AFJSONRequestOperation *op = [AFJSONRequestOperationJSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {

       NSDictionary *dictionary = JSON;

       int ret = [[dictionary objectForKey:@"ret"] intValue];

        //对服务器返回数据进行判断

       switch (ret) {

           case -1:

                [selfshowAlertWithString:@"用户未登录"];

               break;

           case 1:

                [selfsaveDataToCurrentAccount];

                [selfshowAlertWithDelegateWithString:@"保存成功"];

               break;

           case -2:

                [selfshowAlertWithString:@"保存失败"];

               break;

        }

    }failure:^(NSURLRequest *request,NSHTTPURLResponse *response, NSError *error, id JSON) {

        [selfshowAlertWithString:[NSStringstringWithFormat:@"%@", error.localizedDescription]];

    }];

    [opstart];

NSString *urlString = [NSStringstringWithFormat:@"xxxxxxxx"];

    //有中文，需要转换

    urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

   NSURL *url = [NSURLURLWithString:urlString];

    NSURLRequest *request = [NSURLRequestrequestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicytimeoutInterval:4.0f];

    AFHTTPRequestOperation *op = [[AFHTTPRequestOperationalloc] initWithRequest:request];

    op.responseSerializer = [AFJSONResponseSerializerserializer];

    [opsetCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation,id responseObject) {

       NSDictionary *dictionary = responseObject;

       int ret = [[dictionary objectForKey:@"ret"] intValue];

        //对服务器返回数据进行判断

       switch (ret) {

           case -1:

                [selfshowAlertWithString:@"用户未登录"];

               break;

           case 1:

                [selfsaveDataToCurrentAccount];

                [selfshowAlertWithDelegateWithString:@"保存成功"];

               break;

           case -2:

                [selfshowAlertWithString:@"保存失败"];

               break;

        }

    }failure:^(AFHTTPRequestOperation *operation,NSError *error) {

        [selfshowAlertWithString:[NSStringstringWithFormat:@"%@", error.localizedDescription]];

    }];

    [[NSOperationQueuemainQueue] addOperation:op];