使用post请求下载数据

//下载数据
-(void)requestData
{
    NSURL *url = [NSURL URLWithString:kVerify];
    //转码
    //urlStr= [url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    request.HTTPMethod = @"POST";   //设置请求方法
    NSString *param = [NSString stringWithFormat:@"sign=02D4CB5771C7AE0EB03C6A7F3163805A&v=2015061201&t=1440916340&phone_number=18296118078&appkey=9&from=0123456789&code=%@&openId=",_verifyTField.text];
    request.timeoutInterval = 3;
    request.HTTPBody = [param dataUsingEncoding:NSUTF8StringEncoding];

    NSHTTPURLResponse *response = nil;
    NSError *error = nil;
    NSData *data =  [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
    id result = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
    if ([result isKindOfClass:[NSDictionary class]]) {
        NSDictionary *dic = result;
        if ([dic[@"ret"] integerValue] != -19) {
            _msgLabel.text = @"查找手机号验证信息失败";
        }
        else
        {
            _msgLabel.text = nil;
            //_userDic = dic[@"data"];
        }
    }
}