字符串的处理类

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Text.RegularExpressions; 

namespace BIReportCenter.Utility 
{ 
public class StringHelper 
{ 
#region String length formatter 

/// <summary> 
/// 对字符串进行裁剪 
/// </summary> 
public static string Trim(string stringTrim, int maxLength) 
{ 
return Trim(stringTrim, maxLength, "..."); 
} 

/// <summary> 
/// 对字符串进行裁剪(区分单字节及双字节字符) 
/// </summary> 
/// <param name="rawString">需要裁剪的字符串</param> 
/// <param name="maxLength">裁剪的长度，按双字节计数</param> 
/// <param name="appendString">如果进行了裁剪需要附加的字符</param> 
public static string Trim(string rawString, int maxLength, string appendString) 
{ 
if (string.IsNullOrEmpty(rawString) || rawString.Length <= maxLength) 
{ 
return rawString; 
} 
else 
{ 
int rawStringLength = Encoding.UTF8.GetBytes(rawString).Length; 
if (rawStringLength <= maxLength * 2) 
return rawString; 
} 

int appendStringLength = Encoding.UTF8.GetBytes(appendString).Length; 
StringBuilder checkedStringBuilder = new StringBuilder(); 
int appendedLenth = 0; 
for (int i = 0; i < rawString.Length; i++) 
{ 
char _char = rawString[i]; 
checkedStringBuilder.Append(_char); 

appendedLenth += Encoding.Default.GetBytes(new char[] { _char }).Length; 

if (appendedLenth >= maxLength * 2 - appendStringLength) 
break; 
} 

return checkedStringBuilder.ToString() + appendString; 
} 


#endregion 

#region 特殊字符 

/// <summary> 
/// 检测是否有Sql危险字符 
/// </summary> 
/// <param name="str">要判断字符串</param> 
/// <returns>判断结果</returns> 
public static bool IsSafeSqlString(string str) 
{ 
return !Regex.IsMatch(str, @"[-|;|,|\/|||
|
|\}|\{|%|@|\*|!|\']"); 
} 

/// <summary> 
/// 删除SQL注入特殊字符 
/// 解然 20070622加入对输入参数sql为Null的判断 
/// </summary> 
public static string StripSQLInjection(string sql) 
{ 
if (!string.IsNullOrEmpty(sql)) 
{ 
//过滤 ' -- 
string pattern1 = @"(\%27)|(\')|(\-\-)"; 

//防止执行 ' or 
string pattern2 = @"((\%27)|(\'))\s*((\%6F)|o|(\%4F))((\%72)|r|(\%52))"; 

//防止执行sql server 内部存储过程或扩展存储过程 
string pattern3 = @"\s+exec(\s|\+)+(s|x)p\w+"; 

sql = Regex.Replace(sql, pattern1, string.Empty, RegexOptions.IgnoreCase); 
sql = Regex.Replace(sql, pattern2, string.Empty, RegexOptions.IgnoreCase); 
sql = Regex.Replace(sql, pattern3, string.Empty, RegexOptions.IgnoreCase); 
} 
return sql; 
} 

public static string SQLSafe(string Parameter) 
{ 
Parameter = Parameter.ToLower(); 
Parameter = Parameter.Replace("'", ""); 
Parameter = Parameter.Replace(">", ">"); 
Parameter = Parameter.Replace("<", "<"); 
Parameter = Parameter.Replace("\n", "<br>"); 
Parameter = Parameter.Replace("\0", "·"); 
return Parameter; 
} 

/// <summary> 
/// 清除xml中的不合法字符 
/// </summary> 
/// <remarks> 
/// 无效字符： 
/// 0x00 - 0x08 
/// 0x0b - 0x0c 
/// 0x0e - 0x1f 
/// </remarks> 
public static string CleanInvalidCharsForXML(string input) 
{ 
if (string.IsNullOrEmpty(input)) 
return input; 
else 
{ 
StringBuilder checkedStringBuilder = new StringBuilder(); 
Char[] chars = input.ToCharArray(); 
for (int i = 0; i < chars.Length; i++) 
{ 
int charValue = Convert.ToInt32(chars[i]); 

if ((charValue >= 0x00 && charValue <= 0x08) || (charValue >= 0x0b && charValue <= 0x0c) || (charValue >= 0x0e && charValue <= 0x1f)) 
continue; 
else 
checkedStringBuilder.Append(chars[i]); 
} 

return checkedStringBuilder.ToString(); 

//string result = checkedStringBuilder.ToString(); 
//result = result.Replace("&#x0;", ""); 
//return Regex.Replace(result, @"[\u0000-\u0008\u000B\u000C\u000E-\u001A\uD800-\uDFFF]", delegate(Match m) { int code = (int)m.Value.ToCharArray()[0]; return (code > 9 ? "&#" + code.ToString() : "&#0" + code.ToString()) + ";"; }); 
} 
} 


/// <summary> 
/// 改正sql语句中的转义字符 
/// </summary> 
public static string mashSQL(string str) 
{ 
return (str == null) ? "" : str.Replace("\'", "'"); 
} 

/// <summary> 
/// 替换sql语句中的有问题符号 
/// </summary> 
public static string ChkSQL(string str) 
{ 
return (str == null) ? "" : str.Replace("'", "''"); 
} 

/// <summary> 
/// 判断是否有非法字符 
/// </summary> 
/// <param name="strString"></param> 
/// <returns>返回TRUE表示有非法字符，返回FALSE表示没有非法字符。</returns> 
public static bool CheckBadStr(string strString) 
{ 
bool outValue = false; 
if (strString != null && strString.Length > 0) 
{ 
string[] bidStrlist = new string[9]; 
bidStrlist[0] = "'"; 
bidStrlist[1] = ";"; 
bidStrlist[2] = ":"; 
bidStrlist[3] = "%"; 
bidStrlist[4] = "@"; 
bidStrlist[5] = "&"; 
bidStrlist[6] = "#"; 
bidStrlist[7] = "\""; 
bidStrlist[8] = "net user"; 
bidStrlist[9] = "exec"; 
bidStrlist[10] = "net localgroup"; 
bidStrlist[11] = "select"; 
bidStrlist[12] = "asc"; 
bidStrlist[13] = "char"; 
bidStrlist[14] = "mid"; 
bidStrlist[15] = "insert"; 
bidStrlist[19] = "order"; 
bidStrlist[20] = "exec"; 
bidStrlist[21] = "delete"; 
bidStrlist[22] = "drop"; 
bidStrlist[23] = "truncate"; 
bidStrlist[24] = "xp_cmdshell"; 
bidStrlist[25] = "<"; 
bidStrlist[26] = ">"; 
string tempStr = strString.ToLower(); 
for (int i = 0; i < bidStrlist.Length; i++) 
{ 
if (tempStr.IndexOf(bidStrlist[i]) != -1) 
//if (tempStr == bidStrlist[i]) 
{ 
outValue = true; 
break; 
} 
} 
} 
return outValue; 
} 

#endregion 

#region Tools 
/// <summary> 
/// 去掉最后一个逗号 
/// </summary> 
/// <param name="String">要做处理的字符串</param> 
/// <returns>去掉最后一个逗号的字符串</returns> 
public static string DelLastComma(string String) 
{ 
if (String.IndexOf(",") == -1) 
{ 
return String; 
} 
return String.Substring(0, String.LastIndexOf(",")); 
} 

/// <summary> 
/// 删除最后一个字符 
/// </summary> 
/// <param name="str"></param> 
/// <returns></returns> 
public static string ClearLastChar(string str) 
{ 
return (str == "") ? "" : str.Substring(0, str.Length - 1); 
} 
/// <summary> 
/// html编码 
/// </summary> 
/// <param name="chr"></param> 
/// <returns></returns> 
public static string html_text(string chr) 
{ 
if (chr == null) 
return ""; 
chr = chr.Replace("'", "''"); 
chr = chr.Replace("<", "<"); 
chr = chr.Replace(">", ">"); 
return (chr); 
} 
/// <summary> 
/// html解码 
/// </summary> 
/// <param name="chr"></param> 
/// <returns></returns> 
public static string text_html(string chr) 
{ 
if (chr == null) 
return ""; 
chr = chr.Replace("<", "<"); 
chr = chr.Replace(">", ">"); 
return (chr); 
} 
public static bool JustifyStr(string strValue) 
{ 
bool flag = false; 
char[] str = "^<>'=&*, ".ToCharArray(0, 8); 
for (int i = 0; i < 8; i++) 
{ 
if (strValue.IndexOf(str[i]) != -1) 
{ 
flag = true; 
break; 
} 
} 
return flag; 
} 
public static string CheckOutputString(string key) 
{ 
string OutputString = string.Empty; 
OutputString = key.Replace("<br>", "\n").Replace("<", "<").Replace(">", ">").Replace(" ", " "); 
return OutputString; 

} 
#endregion 
} 
}