关于json 为什么服务端提示我访问了两次

为啥在服务器端提示我访问了两次（在//1 和//2）呢   我只想做一次数据的交互 请问是什么地方的问题基本是这个过程  当点击categorybutton的时候  将name等信息post到服务端  然后跳转到CategoryTableView中 在跳转之前在从服务端获得 一个json 并且解析 最后显示在那个table中-(IBAction)categoryButton:(id)sender{
        //post提交
        NSString *urlString=@"http://192.168.1.6:8080/iphone/jsonTest.action";
    NSString *bodyString=[NSString stringWithFormat:@"name=%@&clsId=%@&sex=%@",username.text,clsId.text,sex.text];
      [appDelegate.kuaidiParams objectForKey:@"value"],self.searchBar.text];
        NSMutableURLRequest *theRequest=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlString]];
         [theRequest setHTTPBody:[bodyString dataUsingEncoding:NSUTF8StringEncoding]];
         [theRequest setHTTPMethod:@"POST"];
         [theRequest addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
        NSURLResponse *response;
         NSError *error;
         NSData *resultData=[NSURLConnection sendSynchronousRequest:theRequest returningResponse:&response error:&error];//1
        NSXMLParser *xmlParser=[[[NSXMLParser alloc] initWithData:resultData] autorelease];
         [xmlParser parse];        category = [[CategoryTableViewController alloc]
                                           initWithNibName:@"CategoryTableViewController" bundle:nil];
       
        Growsoft_itemAppDelegate *delegate = [[UIApplication sharedApplication]delegate];
        category.title = @"商品类别";
        category.myData = [[MyDataSource fetchLibraryInformation]retain];
       
        [delegate.navController pushViewController:category animated:YES];
}@implementation MyDataSource
+(NSDictionary *) fetchLibraryInformation{
        NSString *urlString = [NSString stringWithFormat:@"http://192.168.1.6:8080/iphone/jsonTest.action"];                                               
        NSURL *url = [NSURL URLWithString:urlString];
        NSLog(@"fetching library data");
        NSString *aa= [self fetchJSONValueForURL:url];
        NSLog(@"%@<--url",aa);
        return aa;
}
+(id)fetchJSONValueForURL:(NSURL *)url{
        NSString *jsonString = [[NSString alloc] initWithContentsOfURL:url
                                                                                                                  encoding:NSUTF8StringEncoding error:nil];//2
        id jsonValue = [jsonString JSONValue];
        [jsonString release];
        NSLog(@"%@<--JSONValue",jsonValue);
        return jsonValue;
       
}@end