过滤敏感字的算法

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
* 算法思路：把敏感词的第一个字符取出来，作为比较对象。
* 遍历整个字符串，如果发现字符跟敏感词第一个字符相同，
* 就从字符串取出跟关键词相同长度的子串比较，如果相同就替换
*
* 本算法比较适合敏感词都不长的场合
* @author Administrator
*
*/
public class WordFilter {
private static Map<Character,List<String>> wordListToMap(List<String> sensitiveWordList){
Map<Character,List<String>> result=new HashMap<Character,List<String>>();
for (String s:sensitiveWordList){
char c=s.charAt(0);
List<String> strs=result.get(c);
if (strs==null){
strs=new ArrayList<String>();
result.put(c,strs);
}
strs.add(s);
}

return result;
}

public static String filter(String src,List<String> sensitiveWordList){
Map<Character,List<String>> wordMap=wordListToMap(sensitiveWordList);

StringBuilder strb=new StringBuilder();
for (int i=0;i<src.length();i++){
char c=src.charAt(i);
String find=null;
if (wordMap.containsKey(c)){
List<String> words=wordMap.get(c);
for (String s:words){
String temp=src.substring(i,(s.length()<=(src.length()-i))?i+s.length():i);
if (s.equals(temp)){
find=s;
break;
}
}
}
if (find!=null){
strb.append("***");
i+=(find.length()-1);
} else {
strb.append(c);
}
}
return strb.toString();
}
/**
* @param args
*/
public static void main(String[] args) {
List<String> wordList=new ArrayList<String>();
wordList.add("TMD");
wordList.add("变态");
System.out.println(filter("你TMD，也太缺德了吧",wordList));
System.out.println(filter("你TMD，也太缺德了TMD吧",wordList));
System.out.println(filter("你TMD，也太缺德了吧TM",wordList));
System.out.println(filter("你TMD，也太缺德了，太变态了吧TM",wordList));
wordList.add("TM");
System.out.println(filter("你TMD，也太缺德了，太变态了吧TM",wordList));
}

}