C#实现过滤sql特殊字符的方法集合

本文实例讲述了c#实现过滤sql特殊字符的方法集合。分享给大家供大家参考，具体如下：

1.

/// <summary>
/// 过滤不安全的字符串
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static 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>
public static 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>
public static 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.

public static 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;
}

希望本文所述对大家c#程序设计有所帮助。