1.url编码
string s = "=%D3%AA%CA%D5_0%B7%D1%D3%C3%D5%CA%C4%BF"; string result = System.Web.HttpUtility.UrlDecode(b, System.Text.Encoding.GetEncoding("GB2312"));
2. MjMzNTE1YWI%3D----Base64转utf-8
