在网站中进行敏感词过滤是非常必要的。

先写一个过滤器

public class WordValidator implements Filter{private WordValidatorUtil wordValidatorUtil=new WordValidatorUtil(); @Overridepublic void destroy() {wordValidatorUtil=null;}@Overridepublic void doFilter(ServletRequest arg0, ServletResponse arg1,FilterChain arg2) throws IOException, ServletException {HttpServletRequest request= (HttpServletRequest) arg0;HttpServletResponse response = (HttpServletResponse) arg1;String txt=request.getParameter("txt");if(txt!=null){Boolean bool = wordValidatorUtil.isContaintSensitiveWord(txt, 1);if(bool==true){System.out.println("有敏感词");PrintWriter writer=response.getWriter();writer.print(common.util.Status.SENSITIVE_WORD_TRUE);writer.flush();writer.close();}else {System.out.println("没有敏感词");arg2.doFilter(arg0, arg1);}}else {arg2.doFilter(arg0, arg1);}return;}@Overridepublic void init(FilterConfig arg0) throws ServletException {}}//WordValidatorUtil 类 判断输入是否包含关键字public class WordValidatorUtil {private Map sensitiveWordMap = null;public static int minMatchTYpe = 1;      //最小匹配规则public static int maxMatchType = 2;      //最大匹配规则/*** 构造函数，初始化敏感词库*/public WordValidatorUtil(){WordValidatorInit wordValidatorInit=new WordValidatorInit();sensitiveWordMap=wordValidatorInit.initKeyWord();}/*** 判断文字是否包含敏感字符* @param txt  文字* @param matchType  匹配规则 1：最小匹配规则，2：最大匹配规则* @return 若包含返回true，否则返回false* @version 1.0*/public boolean isContaintSensitiveWord(String txt,int matchType){boolean flag = false;for(int i = 0 ; i < txt.length() ; i++){int matchFlag = this.CheckSensitiveWord(txt, i, matchType); //判断是否包含敏感字符if(matchFlag > 0){    //大于0存在，返回trueflag = true;}}return flag;}/*** 检查文字中是否包含敏感字符，检查规则如下：
* @author chenming * @param beginIndex* @param matchType* @return，如果存在，则返回敏感词字符的长度，不存在返回0*/public int CheckSensitiveWord(String txt,int beginIndex,int matchType){boolean  flag = false;    //敏感词结束标识位：用于敏感词只有1位的情况int matchFlag = 0;     //匹配标识数默认为0char word = 0;Map nowMap = sensitiveWordMap;for(int i = beginIndex; i < txt.length() ; i++){word = txt.charAt(i);nowMap = (Map) nowMap.get(word);     //获取指定keyif(nowMap != null){     //存在，则判断是否为最后一个matchFlag++;     //找到相应key，匹配标识+1 if("1".equals(nowMap.get("isEnd"))){       //如果为最后一个匹配规则,结束循环，返回匹配标识数flag = true;       //结束标志位为true   if(WordValidatorUtil.minMatchTYpe == matchType){    //最小规则，直接返回,最大规则还需继续查找break;}}}else{     //不存在，直接返回break;}}if(matchFlag < 2 || !flag){        //长度必须大于等于1，为词 matchFlag = 0;}return matchFlag;}}//敏感词库初始化public class WordValidatorInit {private String ENCODING = "UTF-8";    //字符编码public HashMap sensitiveWordMap;/*** * @version 1.0*/public Map initKeyWord(){try {//读取敏感词库Set
    
      keyWordSet = readSensitiveWordFile();//将敏感词库加入到HashMap中addSensitiveWordToHashMap(keyWordSet);//spring获取application，然后application.setAttribute("sensitiveWordMap",sensitiveWordMap);} catch (Exception e) {e.printStackTrace();}return sensitiveWordMap;}/*** @param keyWordSet  敏感词库* @version 1.0*/private void addSensitiveWordToHashMap(Set
     
       keyWordSet) {sensitiveWordMap = new HashMap(keyWordSet.size());     //初始化敏感词容器，减少扩容操作String key = null;  Map nowMap = null;Map
      
        newWorMap = null;//迭代keyWordSetIterator
       
         iterator = keyWordSet.iterator();while(iterator.hasNext()){key = iterator.next();    //关键字nowMap = sensitiveWordMap;for(int i = 0 ; i < key.length() ; i++){char keyChar = key.charAt(i);       //转换成char型Object wordMap = nowMap.get(keyChar);       //获取if(wordMap != null){        //如果存在该key，直接赋值nowMap = (Map) wordMap;}else{     //不存在则，则构建一个map，同时将isEnd设置为0，因为他不是最后一个newWorMap = new HashMap
        
         ();newWorMap.put("isEnd", "0");     //不是最后一个nowMap.put(keyChar, newWorMap);nowMap = newWorMap;}if(i == key.length() - 1){nowMap.put("isEnd", "1");    //最后一个}}}}/*** 读取敏感词库中的内容，将内容添加到set集合中* @return* @version 1.0* @throws Exception */private Set
         
           readSensitiveWordFile() throws Exception{Set
          
            set = null;File file = new File(getClass().getClassLoader().getResource("SensitiveWord.txt").getPath());    //读取文件InputStreamReader read = new InputStreamReader(new FileInputStream(file),ENCODING);try {if(file.isFile() && file.exists()){      //文件流是否存在set = new HashSet
           
            ();BufferedReader bufferedReader = new BufferedReader(read);String txt = null;while((txt = bufferedReader.readLine()) != null){    //读取文件，将文件内容放入到set中set.add(txt);   }}else{         //不存在抛出异常信息throw new Exception("敏感词库文件不存在");}} catch (Exception e) {throw e;}finally{read.close();     //关闭文件流}return set;}}