实现 该 敏感词过滤 采用的是 dfa算法，参考文章：
具体 实现 步骤 如下：
第一步，构建 敏感词库（wordslibrary） 类：
我要评论using system.collections.generic;
using system.linq;
using system;
namespace contentsafe.sensitiveword
{
/// <summary>
/// 敏感词库
/// </summary>
public class wordslibrary
{
/// <summary>
/// 词库树结构类
/// </summary>
public class itemtree
{
public char item { get; set; }
public bool isend { get; set; }
public list<itemtree> child { get; set; }
}
/// <summary>
/// 词库树
/// </summary>
public itemtree library { get; private set; }
/// <summary>
/// 敏感词组
/// </summary>
public string[] words { get; protected set; }
/// <summary>
/// 敏感词库
/// </summary>
public wordslibrary()
{
loadwords();
init();
}
/// <summary>
/// 敏感词库
/// </summary>
/// <param name="words">敏感词组</param>
public wordslibrary(string[] words) : this()
{
words = words;
}
/// <summary>
/// 加载 敏感词组，可被重写以自定义 如何加载 敏感词组
/// </summary>
public virtual void loadwords()
{
}
/// <summary>
/// 词库初始化
/// </summary>
private void init()
{
if (words == null)
words = new[] { "" };
library = new itemtree() { item = 'r', isend = false, child = createtree(words) };
}
/// <summary>
/// 创建词库树
/// </summary>
/// <param name="words">敏感词组</param>
/// <returns></returns>
private list<itemtree> createtree(string[] words)
{
list<itemtree> tree = null;
if (words != null && words.length > 0)
{
tree = new list<itemtree>();
foreach (var item in words)
if (!string.isnullorempty(item))
{
char cha = item[0];
itemtree node = tree.find(e => e.item == cha);
if (node != null)
addchildtree(node, item);
else
tree.add(createsingletree(item));
}
}
return tree;
}
/// <summary>
/// 创建单个完整树
/// </summary>
/// <param name="word">单个敏感词</param>
/// <returns></returns>
private itemtree createsingletree(string word)
{
//根节点，此节点 值为空
itemtree root = new itemtree();
//移动 游标
itemtree p = root;
for (int i = 0; i < word.length; i++)
{
itemtree child = new itemtree() { item = word[i], isend = false, child = null };
p.child = new list<itemtree>() { child };
p = child;
}
p.isend = true;
return root.child.first();
}
/// <summary>
/// 附加分支子树
/// </summary>
/// <param name="childtree">子树</param>
/// <param name="word">单个敏感词</param>
private void addchildtree(itemtree childtree, string word)
{
//移动 游标
itemtree p = childtree;
for (int i = 1; i < word.length; i++)
{
char cha = word[i];
list<itemtree> child = p.child;
if (child == null)
{
itemtree node = new itemtree() { item = cha, isend = false, child = null };
p.child = new list<itemtree>() { node };
p = node;
}
else
{
itemtree node = child.find(e => e.item == cha);
if (node == null)
{
node = new itemtree() { item = cha, isend = false, child = null };
child.add(node);
p = node;
}
else
p = node;
}
}
p.isend = true;
}
}
}
第二步，构建 敏感词检测（contentcheck） 类：
using system.collections.generic;
using system.linq;
using system;
namespace contentsafe.sensitiveword
{
/// <summary>
/// 敏感词检测
/// </summary>
public class contentcheck
{
/// <summary>
/// 检测文本
/// </summary>
public string text { private get; set; }
/// <summary>
/// 敏感词库 词树
/// </summary>
public wordslibrary.itemtree library { private get; set; }
/// <summary>
/// 敏感词检测
/// </summary>
public contentcheck() { }
/// <summary>
/// 敏感词检测
/// </summary>
/// <param name="library">敏感词库</param>
public contentcheck(wordslibrary library)
{
if (library.library == null)
throw new exception("敏感词库未初始化");
library = library.library;
}
/// <summary>
/// 敏感词检测
/// </summary>
/// <param name="library">敏感词库</param>
/// <param name="text">检测文本</param>
public contentcheck(wordslibrary library, string text) : this(library)
{
if (text == null)
throw new exception("检测文本不能为null");
text = text;
}
/// <summary>
/// 检测敏感词
/// </summary>
/// <param name="text">检测文本</param>
/// <returns></returns>
private dictionary<int, char> wordscheck(string text)
{
if (library == null)
throw new exception("未设置敏感词库 词树");
dictionary<int, char> dic = new dictionary<int, char>();
wordslibrary.itemtree p = library;
list<int> indexs = new list<int>();
for (int i = 0, j = 0; j < text.length; j++)
{
char cha = text[j];
var child = p.child;
var node = child.find(e => e.item == cha);
if (node != null)
{
indexs.add(j);
if (node.isend || node.child == null)
{
if (node.child != null)
{
int k = j + 1;
if (k < text.length && node.child.exists(e => e.item == text[k]))
{
p = node;
continue;
}
}
foreach (var item in indexs)
dic.add(item, text[item]);
indexs.clear();
p = library;
i = j;
++i;
}
else
p = node;
}
else
{
indexs.clear();
if (p.gethashcode() != library.gethashcode())
{
++i;
j = i;
p = library;
}
else
i = j;
}
}
return dic;
}
/// <summary>
/// 替换敏感词
/// </summary>
/// <param name="library">敏感词库</param>
/// <param name="text">检测文本</param>
/// <param name="newchar">替换字符</param>
/// <returns></returns>
public static string sensitivewordsreplace(wordslibrary library, string text, char newchar = '*')
{
dictionary<int, char> dic = new contentcheck(library).wordscheck(text);
if (dic != null && dic.keys.count > 0)
{
char[] chars = text.tochararray();
foreach (var item in dic)
chars[item.key] = newchar;
text = new string(chars);
}
return text;
}
/// <summary>
/// 替换敏感词
/// </summary>
/// <param name="text">检测文本</param>
/// <param name="newchar">替换字符</param>
/// <returns></returns>
public string sensitivewordsreplace(string text, char newchar = '*')
{
dictionary<int, char> dic = wordscheck(text);
if (dic != null && dic.keys.count > 0)
{
char[] chars = text.tochararray();
foreach (var item in dic)
chars[item.key] = newchar;
text = new string(chars);
}
return text;
}
/// <summary>
/// 替换敏感词
/// </summary>
/// <param name="newchar">替换字符</param>
/// <returns></returns>
public string sensitivewordsreplace(char newchar = '*')
{
if (text == null)
throw new exception("未设置检测文本");
return sensitivewordsreplace(text, newchar);
}
/// <summary>
/// 查找敏感词
/// </summary>
/// <param name="library">敏感词库</param>
/// <param name="text">检测文本</param>
/// <returns></returns>
public static list<string> findsensitivewords(wordslibrary library, string text)
{
contentcheck check = new contentcheck(library, text);
return check.findsensitivewords();
}
/// <summary>
/// 查找敏感词
/// </summary>
/// <param name="text">检测文本</param>
/// <returns></returns>
public list<string> findsensitivewords(string text)
{
dictionary<int, char> dic = wordscheck(text);
if (dic != null && dic.keys.count > 0)
{
int i = -1;
string str = "";
list<string> list = new list<string>();
foreach(var item in dic)
{
if (i == -1 || i + 1 == item.key)
str += item.value;
else
{
list.add(str);
str = "" + item.value;
}
i = item.key;
}
list.add(str);
return list.distinct().tolist();
}
else
return null;
}
/// <summary>
/// 查找敏感词
/// </summary>
/// <returns></returns>
public list<string> findsensitivewords()
{
if (text == null)
throw new exception("未设置检测文本");
return findsensitivewords(text);
}
}
}
第三步，测试与使用方法：
string[] words = new[] { "敏感词1", "敏感词2", "含有", "垃圾" }; //敏感词组 可自行在网上 搜索下载
//敏感词库 类可被继承，如果想实现自定义 敏感词导入方法 可以 对 loadwords 方法进行 重写
var library = new wordslibrary(words); //实例化 敏感词库
string text = "在任意一个文本中都可能包含敏感词1、2、3等等，只要含有敏感词都会被找出来，比如：垃圾";
contentcheck check = new contentcheck(library, text); //实例化 内容检测类
var list = check.findsensitivewords(); //调用 查找敏感词方法 返回敏感词列表
var str = check.sensitivewordsreplace(); //调用 敏感词替换方法 返回处理过的字符串
该 实现方案 不止 这个 使用方法，更多使用方法 可自行 研究
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