C#和Java中正则写法的代码转换

Question

public static string getQueryString(string url, string name)
    {
        if (url == "") return "";
        System.Text.RegularExpressions.Regex re = new System.Text.RegularExpressions.Regex(@"(^|&)?(\w+)=([^&]+)(&|$)?", System.Text.RegularExpressions.RegexOptions.Compiled);
        System.Text.RegularExpressions.MatchCollection mc = re.Matches(url);
        foreach (System.Text.RegularExpressions.Match m in mc)
        {
            if (m.Result("$2").Equals(name))
            {
                return m.Result("$3");
            }
        }
        return "";
    }

上面是C#的代码，用Java代码怎么写？