基于java实现DFA算法代码实例

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;

/**

* 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;http://

/**

* 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 nZrGQWlength = 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.sihttp://ze(); 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 linZrGQWst = 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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