本文實(shí)例講述了高效.NET臟字過(guò)濾算法。分享給大家供大家參考,具體如下:
BadWordsFilter.cs類
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Collections;
using System.Data;
namespace WNF
{
public class BadWordsFilter
{
private HashSetstring> hash = new HashSetstring>(); //關(guān)鍵字
private byte[] fastCheck = new byte[char.MaxValue];
private byte[] fastLength = new byte[char.MaxValue];
private BitArray charCheck = new BitArray(char.MaxValue);
private BitArray endCheck = new BitArray(char.MaxValue);
private int maxWordLength = 0;
private int minWordLength = int.MaxValue;
public BadWordsFilter()
{
}
//初始化關(guān)鍵字
public void Init(DataTable badwords)
{
for (int j = 0; j badwords.Rows.Count; j++)
{
string word = badwords.Rows[j][0].ToString();
maxWordLength = Math.Max(maxWordLength, word.Length);
minWordLength = Math.Min(minWordLength, word.Length);
for (int i = 0; i 7 i word.Length; i++)
{
fastCheck[word[i]] |= (byte)(1 i);
}
for (int i = 7; i word.Length; i++)
{
fastCheck[word[i]] |= 0x80;
}
if (word.Length == 1)
{
charCheck[word[0]] = true;
}
else
{
fastLength[word[0]] |= (byte)(1 (Math.Min(7, word.Length - 2)));
endCheck[word[word.Length - 1]] = true;
hash.Add(word);
}
}
}
public string Filter(string text, string mask)
{
throw new NotImplementedException();
}
//檢查是否有關(guān)鍵字
public bool HasBadWord(string text)
{
int index = 0;
while (index text.Length)
{
int count = 1;
if (index > 0 || (fastCheck[text[index]] 1) == 0)
{
while (index text.Length - 1 (fastCheck[text[++index]] 1) == 0) ;
}
char begin = text[index];
if (minWordLength == 1 charCheck[begin])
{
return true;
}
for (int j = 1; j = Math.Min(maxWordLength, text.Length - index - 1); j++)
{
char current = text[index + j];
if ((fastCheck[current] 1) == 0)
{
++count;
}
if ((fastCheck[current] (1 Math.Min(j, 7))) == 0)
{
break;
}
if (j + 1 >= minWordLength)
{
if ((fastLength[begin] (1 Math.Min(j - 1, 7))) > 0 endCheck[current])
{
string sub = text.Substring(index, j + 1);
if (hash.Contains(sub))
{
return true;
}
}
}
}
index += count;
}
return false;
}
}
}
引用:
string sql = "select keywords from tb_keyword";
BadWordsFilter badwordfilter = new BadWordsFilter();
//初始化關(guān)鍵字
badwordfilter.Init(oEtb.GetDataSet(sql).Tables[0]);
//檢查是否有存在關(guān)鍵字
bool a = badwordfilter.HasBadWord(TextBox1.Text);
if (a == true)
{
Page.RegisterClientScriptBlock("a", "script>alert('該評(píng)論含有不合法文字!')/script>");
}
else
{
PingLun();//寫入評(píng)論表
}
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