{

    // Create zero addy

    struct sockaddr_in zeroAddress;

    bzero(&zeroAddress, sizeof(zeroAddress));

    zeroAddress.sin_len = sizeof(zeroAddress);

    zeroAddress.sin_family = AF_INET;

    // Recover reachability flags

    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);

    SCNetworkReachabilityFlags flags;

    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);

    CFRelease(defaultRouteReachability);

    if (!didRetrieveFlags)

    {

        NSLog(@"Error. Could not recover network reachability flags");

        return NO;

    }

    BOOL isReachable = flags & kSCNetworkFlagsReachable;

    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;

BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;

／／向苹果网站发送请求，严正URL链接是否成功 

NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];

NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL  cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];

NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];

    return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO;

}