基于java实现DFA算法代码实例

DFA简介

DFA全称为：Deterministic Finite Automaton,即确定有穷自动机。（自己百度吧）

直接代码：

敏感词实体类

package com.nopsmile.dfa;

public class Keywords {
  private String pid;
  private String Content;

  public Keywords() {

  }

  public Keywords(String content) {
    super();
    Content = content;
  }

  public String getContent() {
    return Content;
  }

  public void setContent(String content) {
    Content = content;
  }

  public String getPid() {
    return pid;
  }

  public void setPid(String pid) {
    this.pid = pid;
  }

}

敏感词库初始化

package com.nopsmile.dfa;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;


public class SensitiveWordInit{

  
  public HashMap sensitiveWordMap;

  
  public Map initKeyWord(List sensitiveWords) {
    try {
      // 从敏感词集合对象中取出敏感词并封装到Set集合中
      Set keyWordSet = new HashSet();
      for (Keywords s : sensitiveWords) {
 keyWordSet.add(s.getContent().trim());
      }
      // 将敏感词库加入到HashMap中
      addSensitiveWordToHashMap(keyWordSet);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return sensitiveWordMap;
  }

  
  private void addSensitiveWordToHashMap(Set keyWordSet) {
    // 初始化HashMap对象并控制容器的大小
    sensitiveWordMap = new HashMap(keyWordSet.size());
    // 敏感词
    String key = null;
    // 用来按照相应的格式保存敏感词库数据
    Map nowMap = null;
    // 用来辅助构建敏感词库
    Map newWorMap = null;
    // 使用一个迭代器来循环敏感词集合
    Iterator iterator = keyWordSet.iterator();
    while (iterator.hasNext()) {
      key = iterator.next();
      // 等于敏感词库，HashMap对象在内存中占用的是同一个地址，所以此nowMap对象的变化，sensitiveWordMap对象也会跟着改变
      nowMap = sensitiveWordMap;
      for (int i = 0; i < key.length(); i++) {
 // 截取敏感词当中的字，在敏感词库中字为HashMap对象的Key键值
 char keyChar = key.charAt(i);

 // 判断这个字是否存在于敏感词库中
 Object wordMap = nowMap.get(keyChar);
 if (wordMap != null) {
   nowMap = (Map) wordMap;
 } else {
   newWorMap = new HashMap();
   newWorMap.put("isEnd", "0");
   nowMap.put(keyChar, newWorMap);
   nowMap = newWorMap;
 }

 // 如果该字是当前敏感词的最后一个字，则标识为结尾字
 if (i == key.length() - 1) {
   nowMap.put("isEnd", "1");
 }
      }
    }
  }
}

自定义的工具类

package com.nopsmile.dfa;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.linkedHashMap;
import java.util.linkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.alibaba.fastjson.JSONArray;

import net.sf.json.JSONObject;


public class SensitivewordUtils {
  
  public static Map sensitiveWordMap = null;

  
  public static int minMatchTYpe = 1;

  
  public static int maxMatchType = 2;

  
  public static int getWordSize() {
    if (SensitivewordUtils.sensitiveWordMap == null) {
      return 0;
    }
    return SensitivewordUtils.sensitiveWordMap.size();
  }

  
  public static boolean isContaintSensitiveWord(String txt, int matchType) {
    boolean flag = false;
    for (int i = 0; i < txt.length(); i++) {
      int matchFlag = checkSensitiveWord(txt, i, matchType);
      if (matchFlag > 0) {
 flag = true;
      }
    }
    return flag;
  }

  
  public static Set getSensitiveWord(String txt, int matchType) {
    Set sensitiveWordList = new HashSet();

    for (int i = 0; i < txt.length(); i++) {
      int length = checkSensitiveWord(txt, i, matchType);
      if (length > 0) {
 // 将检测出的敏感词保存到集合中
 sensitiveWordList.add(txt.substring(i, i + length));
 i = i + length - 1;
      }
    }

    return sensitiveWordList;
  }

  
  public static String replaceSensitiveWord(String txt, int matchType, String replaceChar) {
    String resultTxt = txt;
    Set set = getSensitiveWord(txt, matchType);
    Iterator iterator = set.iterator();
    String word = null;
    String replaceString = null;
    while (iterator.hasNext()) {
      word = iterator.next();
      replaceString = getReplaceChars(replaceChar, word.length());
      resultTxt = resultTxt.replaceAll(word, replaceString);
    }

    return resultTxt;
  }

  
  private static String getReplaceChars(String replaceChar, int length) {
    String resultReplace = replaceChar;
    for (int i = 1; i < length; i++) {
      resultReplace += replaceChar;
    }

    return resultReplace;
  }

  
  public static int checkSensitiveWord(String txt, int beginIndex, int matchType) {
    boolean flag = false;
    // 记录敏感词数量
    int matchFlag = 0;
    char word = 0;
    Map nowMap = SensitivewordUtils.sensitiveWordMap;
    for (int i = beginIndex; i < txt.length(); i++) {
      word = txt.charAt(i);
      // 判断该字是否存在于敏感词库中
      nowMap = (Map) nowMap.get(word);
      if (nowMap != null) {
 matchFlag++;
 // 判断是否是敏感词的结尾字，如果是结尾字则判断是否继续检测
 if ("1".equals(nowMap.get("isEnd"))) {
   flag = true;
   // 判断过滤类型，如果是小过滤则跳出循环，否则继续循环
   if (SensitivewordUtils.minMatchTYpe == matchType) {
     break;
   }
 }
      } else {
 break;
      }
    }
    if (!flag) {
      matchFlag = 0;
    }
    return matchFlag;
  }

  
  public static Map getSensitiveWordSum(String txt, int matchType) {
    Map map = new HashMap();
    for (int i = 0; i < txt.length(); i++) {
      int length = checkSensitiveWord(txt, i, matchType);
      if (length > 0) {
 // 将检测出的敏感词保存到集合中
 String str=txt.substring(i, i + length);
 if(map.containsKey(str)) {
   map.put(str, map.get(str).intValue()+1);
 }else {
   map.put(str, new Integer(1));
 }
 //System.out.println(txt.substring(i, i + length));
 i = i + length - 1;
      }
    }
    return map;
  }

  
  public static Map sortByValue(Map unsortMap,int condition,boolean isCondition) {

    // 1. Convert Map to List of Map
    List> list =
 new linkedList>(unsortMap.entrySet());

    // 2. Sort list with Collections.sort(), provide a custom Comparator
    //  Try switch the o1 o2 position for a different order
    Collections.sort(list, new Comparator>() {
      public int compare(Map.Entry o1,
  Map.Entry o2) {
 return (o2.getValue()).compareTo(o1.getValue());
      }
    });

    // 3. Loop the sorted list and put it into a new insertion order Map linkedHashMap
    Map sortedMap = new linkedHashMap();
    if(isCondition) {
      for (int i = 0; i < list.size(); i++) {
 if (i < condition) {
   sortedMap.put(list.get(i).getKey(), list.get(i).getValue());
 }
      }
    }else{
      for (int i = 0; i < list.size(); i++) {
   sortedMap.put(list.get(i).getKey(), list.get(i).getValue());
      }
    }
    return sortedMap;
  }
}

使用上面类流程代码

Keywords ss=new Keywords("好");
List list = new ArrayList();
list.add(ss);

SensitiveWordInit sensitiveWordInit = new SensitiveWordInit();
Map sensitiveWordMap  = sensitiveWordInit.initKeyWord(list);

// 传入SensitivewordEngine类中的敏感词库
SensitivewordUtils.sensitiveWordMap = sensitiveWordMap;

SensitivewordUtils.getSensitiveWordSum("需要检测的文本", 2)  ；

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