NSString *urlString = [NSString stringWithFormat:@"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 = [NSURL URLWithString: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 = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:4.0f];

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

    AFJSONRequestOperation *op = [AFJSONRequestOperation JSONRequestOperationWithRequest: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:

                [self showAlertWithString:@"用户未登录"];

                break;

            case 1:

                [self saveDataToCurrentAccount];

                [self showAlertWithDelegateWithString:@"保存成功"];

                break;

            case -2:

                [self showAlertWithString:@"保存失败"];

                break;

        }

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

        [self showAlertWithString:[NSString stringWithFormat:@"%@", error.localizedDescription]];

    }];

    [op start];

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

    //有中文，需要转换

    urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    NSURL *url = [NSURL URLWithString:urlString];

    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:4.0f];

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

    op.responseSerializer = [AFJSONResponseSerializer serializer];

    [op setCompletionBlockWithSuccess:^(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:

                [self showAlertWithString:@"用户未登录"];

                break;

            case 1:

                [self saveDataToCurrentAccount];

                [self showAlertWithDelegateWithString:@"保存成功"];

                break;

            case -2:

                [self showAlertWithString:@"保存失败"];

                break;

        }

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

        [self showAlertWithString:[NSString stringWithFormat:@"%@", error.localizedDescription]];

    }];

    [[NSOperationQueue mainQueue] addOperation:op];