java 百度式算法_java 实现DFA 算法（理论百度搜索）

痛定思痛。 2022-11-07 05:25 165阅读 0赞

java 实现DFA 算法(理论百度搜索)

发布时间：2020-07-17 21:28:16

来源：51CTO

阅读：924

作者：NopSmile

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;

/\*\*

\* 敏感词库初始化

\*/

public class SensitiveWordInit\{

/\*\*

\* 敏感词库

\*/

public HashMap sensitiveWordMap;

/\*\*

\* 初始化敏感词 keywords

\*/

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;

/\*\*

\* 封装敏感词库

\*/

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;

/\*\*

\* 敏感词过滤工具类

\* @author AlanLee

\*/

public class SensitivewordUtils \{

/\*\*

\* 敏感词库

\*/

public static Map sensitiveWordMap = null;

/\*\*

\* 只过滤最小敏感词

\*/

public static int minMatchTYpe = 1;

/\*\*

\* 过滤所有敏感词

\*/

public static int maxMatchType = 2;

/\*\*

\* 敏感词库敏感词数量

\* @return

\*/

public static int getWordSize() \{

if (SensitivewordUtils.sensitiveWordMap == null) \{

return 0;

return SensitivewordUtils.sensitiveWordMap.size();

/\*\*

\* 是否包含敏感词

\*/

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;

/\*\*

\* 获取敏感词内容

\* @param txt

\* @param matchType

\* @return 敏感词内容

\*/

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;

/\*\*

\* 替换敏感词

\*/

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;

/\*\*

\* 替换敏感词内容

\*/

private static String getReplaceChars(String replaceChar, int length) \{

String resultReplace = replaceChar;

for (int i = 1; i < length; i++) \{

resultReplace += replaceChar;

return resultReplace;

/\*\*

\* 检查敏感词数量

\*/

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;

/\*\*

\* 敏感词汇对应个数

\* 返回 "关键字"="关键字个数"

\*/

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;

/\*\*

\* 对map数组value排序，并取前10

\* this method will always sort the map;

\* isCondition is true condition can be used otherwise invalid

\* @param unsortMap

\* @return

\*/

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) ；

java 百度式算法_java 实现DFA 算法（理论百度搜索）

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