从ituns里面复制的链接是：
https://itunes.apple.com/cn/app/tao-bao-sui-shi-sui-xiang/id387682726?mt=8
需要将https改成AppStore的urlSchemes，即itms-apps
最后用打开openURL方法打开该链接即可。如下：
NSString *urlStr = @"itms-apps://itunes.apple.com/cn/app/tao-bao-sui-shi-sui-xiang/id387682726?mt=8";
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:urlStr]];
补充：手机iTunes Store的urlSchemes为itms，不要弄混。
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"https://itunes.apple.com/cn/app/wan-zhuan-quan-cheng/id692579125?mt=8"]];