iphone - 如何将 XML 数据从 iOS 应用程序发布到 Web？

Question

我正在尝试将一些 XML 格式的数据发送到我可以注册用户的网页。

我尝试了两种方法，并用两种我感觉的方式来获取数据。

方式一

    NSString *urlString = @"http://****.com/iphone/csi/register.php?choice=register";
    NSURL *url = [NSURL URLWithString: urlString];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: url];
    [request setHTTPMethod: @"POST"];
    [request setValue: @"text/xml" forHTTPHeaderField: @"Content-Type"];

    NSMutableData *highScoreData = [NSMutableData data];
    [highScoreData appendData: [[NSString stringWithFormat: @"<?xml version=\"1.0\" encoding=\"UTF-8\" ?>"] dataUsingEncoding: NSUTF8StringEncoding]];
    [highScoreData appendData: [[NSString stringWithFormat: @"<user_name>%@</user_name", @"test"] dataUsingEncoding: NSUTF8StringEncoding]];
    [highScoreData appendData: [[NSString stringWithFormat: @"<password>%@</password>", @"test"] dataUsingEncoding: NSUTF8StringEncoding]];
    [highScoreData appendData: [[NSString stringWithFormat: @"</xml>"] dataUsingEncoding: NSUTF8StringEncoding]];
    [request setHTTPBody: highScoreData];
    NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest: request
                                                                delegate: self];

方式二

    NSString * xmlString = @"<test><message>Hello</message></test>";        
    NSURL * serviceUrl = [NSURL URLWithString:@"http://demos4clients.com/iphone/csi/register.php?choice=register"];
    NSMutableURLRequest * serviceRequest = [NSMutableURLRequest requestWithURL:serviceUrl];
    [serviceRequest setValue:@"text/xml" forHTTPHeaderField:@"Content-type"];
    [serviceRequest setHTTPMethod:@"POST"];
    [serviceRequest setHTTPBody:[xmlString dataUsingEncoding:NSASCIIStringEncoding]];

    NSURLResponse * serviceResponse;
    NSError * serviceError;
    serviceResponse = [NSURLConnection sendSynchronousRequest:serviceRequest returningResponse:&serviceResponse error:&serviceError];

我怎样才能找到这个错误的原因？