使用场景，当一网站是gb2312的编码向另一个是utf8的网站提交查询
如：http://search.chinayq.com/?key=%C0%D6%C6%F7
其中key为gb2312的url编码
可以自动转换成utf8解码后的汉字
/// <summary>
/// 判断是否是utf8编码
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
private static bool IsUTF8(byte[] buf) {
int i;
byte cOctets; // octets to go in this UTF-8 encoded character
bool bAllAscii = true;
long iLen = buf.Length;
cOctets = 0;
for (i = 0; i < iLen; i++) {
if ((buf[i] & 0x80) != 0) bAllAscii = false;
if (cOctets == 0) {
if (buf[i] >= 0x80) { do { buf[i] <<= 1; cOctets++; }
while ((buf[i] & 0x80) != 0);
cOctets--;
if (cOctets == 0)
return false;
}
}
else {
if ((buf[i] & 0xC0) != 0x80)
return false;
cOctets--;
}
}
if (cOctets > 0)
return false;
if (bAllAscii)
return false;
return true;
}
/// <summary> /// url转换为字节 /// </summary>
/// <param name="url"></param>
/// <returns></returns>
private static byte[] GetUrlCodingToBytes(string url) {
StringBuilder sb = new StringBuilder();
int i = url.IndexOf('%');
while (i >= 0) {
if (url.Length < i + 3) {
break;
}
sb.Append(url.Substring(i, 3));
url = url.Substring(i + 3);
i = url.IndexOf('%');
}
string urlCoding = sb.ToString();
if (string.IsNullOrEmpty(urlCoding))
return new byte[0];
urlCoding = urlCoding.Replace("%", string.Empty);
int len = urlCoding.Length / 2;
byte[] result = new byte[len];
len *= 2;
for (int index = 0; index < len; index++) {
string s = urlCoding.Substring(index, 2);
int b = int.Parse(s, System.Globalization.NumberStyles.HexNumber);
result[index / 2] = (byte)b;
index++;
}
return result;
}
/// <summary>
/// Request得到string类型
/// </summary>
/// <param name="name">参数</param>
/// <param name="sum">最大字符数</param>
/// <returns></returns>
public static string GetString( string name, int sum ) {
HttpRequest request = System.Web.HttpContext.Current.Request;
if (request[name] != null ) {
byte[] url = GetUrlCodingToBytes(request.Url.PathAndQuery);
string str = request[name];
string getStr = Regex.Match(request.Url.Query, "" + name + @"=([\s\S]+)&?$").Groups[1].Value;
if (!IsUTF8(url) && getStr!="") {
str = HttpUtility.UrlDecode(getStr, System.Text.ASCIIEncoding.GetEncoding("gb2312")); } else {
str = HttpUtility.UrlDecode(str); }
if (str.Length > sum) {
str = str.Substring(0, sum); }
return FiltrateDangerCharacter(str); }
else { return string.Empty; } }