发送json给服务器

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // 1.URL
    NSURL *url = [NSURL URLWithString:@"http://localhost:8080/MJServer/order"];

    // 2.请求
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];

    // 3.请求方法
    request.HTTPMethod = @"POST";

    // 4.设置请求体（请求参数）
    // 创建一个描述订单信息的JSON数据
    NSDictionary *orderInfo = @{
                                @"shop_id" : @"1243324",
                                @"shop_name" : @"啊哈哈哈",
                                @"user_id" : @"899"
                                };
    NSData *json = [NSJSONSerialization dataWithJSONObject:orderInfo options:NSJSONWritingPrettyPrinted error:nil];
    request.HTTPBody = json;

    // 5.设置请求头：这次请求体的数据不再是普通的参数，而是一个JSON数据
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

    // 6.发送请求
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        if (data == nil || connectionError) return;
        NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
        NSString *error = dict[@"error"];
        if (error) {
            [MBProgressHUD showError:error];
        } else {
            NSString *success = dict[@"success"];
            [MBProgressHUD showSuccess:success];
        }
    }];

}