连接到服务器

-(void)xmlParsingInBackground
{
NSString xmlString = [NSString stringWithFormat:@\"Your XML REquest\"];
NSURL * serviceUrl = [NSURL URLWithString:[NSString stringWithString:@\"YOUR URL\"]];
NSMutableURLRequest * serviceRequest = [NSMutableURLRequest requestWithURL:serviceUrl];
[serviceRequest setValue:@\"text/xml\" forHTTPHeaderField:@\"Content-type\"];
[serviceRequest setHTTPMethod:@\"POST\"];
[serviceRequest setHTTPBody:[xmlString dataUsingEncoding:NSUTF8StringEncoding]];
NSData *responseData;
NSURLResponse * serviceResponse;
NSError * serviceError;
responseData = [NSURLConnection sendSynchronousRequest:serviceRequest returningResponse:&serviceResponse error:&serviceError];
NSString *resp=[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
if(responseData != NULL)
{       
    NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:responseData];
    [xmlParser setDelegate:self];
    //[xmlParser setDelegate:parser];       
    BOOL success = [xmlParser parse];

    if(success)
    { // DO SOMETHING HERE
            }

}

 - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName 
attributes:(NSDictionary *)attributeDict 

 - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string  

 - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName