如何实现点击UIWebView中链接调用Safari打开目标链接

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType;
{
    NSURL *requestURL =[ [ request URL ] retain ];
    if ( ( [ [ requestURL scheme ] isEqualToString: @"http" ] || [ [ requestURL scheme ] isEqualToString: @"https" ] || [ [ requestURL scheme ] isEqualToString: @"mailto" ])
        && ( navigationType == UIWebViewNavigationTypeLinkClicked ) ) {
        return ![ [ UIApplication sharedApplication ] openURL: [ requestURL autorelease ] ];
    }
    [ requestURL release ];
    return YES;
}