高效.NET脏字过滤算法与应用实例_实用技巧_

 using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Collections; using System.Data; namespace WNF { public class BadWordsFilter { private HashSet hash = new HashSet(); //关键字 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() { } //初始化关键字 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(); } //检查是否有关键字 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; } } } 

 string sql = "select keywords from tb_keyword"; BadWordsFilter badwordfilter = new BadWordsFilter(); //初始化关键字 badwordfilter.Init(oEtb.GetDataSet(sql).Tables[0]); //检查是否有存在关键字 bool a = badwordfilter.HasBadWord(TextBox1.Text); if (a == true) { Page.RegisterClientScriptBlock("a", ""); } else { PingLun();//写入评论表 }