nshttp 请求
urlReques=[[NSString stringWithFormat:@"%@userid=%@&isVisitCount=1&sign=%@",CarUrl,Userid,SignMd5] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@", urlReques);
NSURL *url = [NSURL URLWithString:urlReques];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
NSError *error = nil;
receivedData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:&error];
NSString *xmlString = [[NSString alloc] initWithBytes:[receivedData bytes] length:[receivedData length] encoding:NSUTF8StringEncoding];
/* 下载的数据 */
if (receivedData!= nil){
NSLog(xmlString);
} else {
NSLog(@"%@", error);
}