过滤特殊字符的方法

 

1.
/// <summary>
    /// 过滤不安全的字符串
    /// </summary>
    /// <param name="Str"></param>
    /// <returns></returns>
    publicstatic string FilteSQLStr(string Str)
    {

        Str = Str.Replace("'","");
        Str = Str.Replace("\"","");
        Str = Str.Replace("&","&amp");
        Str = Str.Replace("<","&lt");
        Str = Str.Replace(">","&gt");

        Str = Str.Replace("delete","");
        Str = Str.Replace("update","");
        Str = Str.Replace("insert","");

        return Str;
    }

2.

#region 过滤 Sql 语句字符串中的注入脚本
        /// <summary>
        /// 过滤 Sql 语句字符串中的注入脚本
        /// </summary>
        /// <param name="source">传入的字符串</param>
        /// <returns>过滤后的字符串</returns>
        publicstatic string SqlFilter(string source)
        {
            //单引号替换成两个单引号
            source = source.Replace("'","''");

            //半角封号替换为全角封号，防止多语句执行
            source = source.Replace(";","；");

            //半角括号替换为全角括号
            source = source.Replace("(","（");
            source = source.Replace(")","）");

            ///////////////要用正则表达式替换，防止字母大小写得情况////////////////////

            //去除执行存储过程的命令关键字
            source = source.Replace("Exec","");
            source = source.Replace("Execute","");

            //去除系统存储过程或扩展存储过程关键字
            source = source.Replace("xp_","x p_");
            source = source.Replace("sp_","s p_");

            //防止16进制注入
            source = source.Replace("0x","0 x");

            return source;
        }
        #endregion

3.

/// 过滤SQL字符。
        /// </summary>
        /// <param name="str">要过滤SQL字符的字符串。</param>
        /// <returns>已过滤掉SQL字符的字符串。</returns>
        publicstatic string ReplaceSQLChar(string str)
        {
            if (str== String.Empty)
                return String.Empty; str= str.Replace("'","‘");
            str = str.Replace(";","；");
            str = str.Replace(",",",");
            str = str.Replace("?","?");
            str = str.Replace("<","＜");
            str = str.Replace(">","＞");
            str = str.Replace("(","(");
            str = str.Replace(")",")");
            str = str.Replace("@","＠");
            str = str.Replace("=","＝");
            str = str.Replace("+","＋");
            str = str.Replace("*","＊");
            str = str.Replace("&","＆");
            str = str.Replace("#","＃");
            str = str.Replace("%","％");
            str = str.Replace("$","￥");

            return str;
        }
4.

/// <summary>
/// 过滤标记
/// </summary>
/// <param name="NoHTML">包括HTML，脚本，数据库关键字，特殊字符的源码</param>
/// <returns>已经去除标记后的文字</returns>
public string NoHtml(string Htmlstring)
{
    if (Htmlstring== null)
    {
        return"";
    }
    else
    {
        //删除脚本
         Htmlstring = Regex.Replace(Htmlstring,@"<script[^>]*?>.*?</script>","", RegexOptions.IgnoreCase);
        //删除HTML
        Htmlstring = Regex.Replace(Htmlstring,@"<(.[^>]*)>","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"([\r\n])[\s]+","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"-->","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"<!--.*","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(quot|#34);","\"", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(amp|#38);","&", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(lt|#60);","<", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(gt|#62);",">", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(nbsp|#160);"," ", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(iexcl|#161);","\xa1", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(cent|#162);","\xa2", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(pound|#163);","\xa3", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&(copy|#169);","\xa9", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,@"&#(\d+);","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"xp_cmdshell","", RegexOptions.IgnoreCase);

        //删除与数据库相关的词
         Htmlstring = Regex.Replace(Htmlstring,"select","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"insert","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"delete from","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"count''","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"drop table","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"truncate","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"asc","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"mid","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"char","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"xp_cmdshell","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"exec master","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"net localgroup administrators","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"and","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"net user","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"or","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"net","", RegexOptions.IgnoreCase);
        //Htmlstring = Regex.Replace(Htmlstring, "*", "", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"-","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"delete","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"drop","", RegexOptions.IgnoreCase);
        Htmlstring = Regex.Replace(Htmlstring,"script","", RegexOptions.IgnoreCase);

        //特殊的字符
         Htmlstring = Htmlstring.Replace("<","");
        Htmlstring = Htmlstring.Replace(">","");
        Htmlstring = Htmlstring.Replace("*","");
        Htmlstring = Htmlstring.Replace("-","");
        Htmlstring = Htmlstring.Replace("?","");
        Htmlstring = Htmlstring.Replace("'","''");
        Htmlstring = Htmlstring.Replace(",","");
        Htmlstring = Htmlstring.Replace("/","");
        Htmlstring = Htmlstring.Replace(";","");
        Htmlstring = Htmlstring.Replace("*/","");
        Htmlstring = Htmlstring.Replace("\r\n","");
        Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();

        return Htmlstring;
   }
}

5.

publicstatic bool CheckBadWord(string str)
{
string pattern= @"select|insert|delete|from|count\(|drop table|update|truncate|asc\(|mid\(|char\(|xp_cmdshell|exec   master|netlocalgroup administrators|net user|or|and";
if (Regex.IsMatch(str, pattern, RegexOptions.IgnoreCase))
return true;
return false;
}
public static string Filter(string str)
{
string[] pattern={ "select","insert","delete","from","count\\(","drop table","update","truncate","asc\\(","mid\\(","char\\(","xp_cmdshell","exec   master","netlocalgroup administrators","net user","or","and" };
for (int i= 0; i< pattern.Length; i++)
{
str = str.Replace(pattern[i].ToString(),"");
}
return str;
}