//几种url
href="http://diy.sina.com.cn/cardshow.php" target="_blank">
href=http://video.sina.com.cn/p/sports/k/v/2011-10-17/092261530255.html target="_blank">
href="http://auto.sina.com.cn/?c=spr_web_sina_sina_www_T001">

    public static String getPaperName(String url){
        String res = "";
        Pattern p = Pattern.compile("href=\"?(.*?)[\"|\\s)]");
        Matcher m = p.matcher(url);
        while(m.find()){
            res = m.group(1);
        }
        return res;
    } 
    public static void main(String[] args) {
        System.out.println(getPaperName("href=\"http://diy.sina.com.cn/cardshow.php\" target=\"_blank\">"));
        System.out.println(getPaperName("href=http://video.sina.com.cn/p/sports/k/v/2011-10-17/092261530255.html target=\"_blank\">"));
        System.out.println(getPaperName("href=\"http://auto.sina.com.cn/?c=spr_web_sina_sina_www_T001\">"));
    }

------解决方案--------------------
http(s)?://([\w-]+\.)+[\w-]+(/[\w-./?%&=]*)?