简单的敏感词过滤

代码如下

package com.nowcoder.service;

/*
   User: fanqunsong 
    Date:  2017/12/31
    Time:  11:32
*/

import org.apache.commons.lang.CharUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Service;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

@Service
public class SensitiveService implements InitializingBean {
    private static final Logger logger = LoggerFactory.getLogger(SensitiveService.class);

    /*
    默认敏感词替换
     */
    private static final String DEFAULT_REPLACEMENT = "敏感词";

    private class TrieNode{
       /**
       true，关键词的终结；false 继续
       **/
       private boolean end = false;

        /**
         * key下一个字符，value是对应的节点
         */
        private Map<Character, TrieNode> subNodes = new HashMap<>();

        /**
         * 向指定位置添加节点树
         */
        void addSubNode(Character key, TrieNode node) {
            subNodes.put(key, node);
        }

        /**
         * 获取下个节点
         */
        TrieNode getSubNode(Character key) {
            return subNodes.get(key);
        }

        boolean isKeywordEnd() {
            return end;
        }

        void setKeywordEnd(boolean end) {
            this.end = end;
        }

        public int getSubNodeCount() {
            return subNodes.size();
        }

    }

    /**
     * 根节点
     */
    private TrieNode rootNode = new TrieNode();


    /**
     * 判断是否是一个符号
     */
    private boolean isSymbol(char c) {
        int ic = (int) c;
        // 0x2E80-0x9FFF 东亚文字范围
        return !CharUtils.isAsciiAlphanumeric(c) && (ic < 0x2E80 || ic > 0x9FFF);
    }

    /**
     * 过滤敏感词
     */

    public String filter(String text){
        if(StringUtils.isBlank(text)){
            return text;
        }
        String replacement = DEFAULT_REPLACEMENT;
        StringBuilder result = new StringBuilder();
        TrieNode tempNode = rootNode;
        int begin = 0;  //回滚数
        int position = 0;  //当前比较的位置
        while (position<text.length()){
            char c = text.charAt(position);
            if(isSymbol(c)){
                if(tempNode == rootNode){
                    result.append(c);
                    begin++;
                }
                position++;
                continue;
            }
            tempNode = tempNode.getSubNode(c);
            //当前位置的匹配结束
            if(tempNode == null){
                //以begin开始的字符串不存在敏感词
                result.append(text.charAt(begin));
                //调到下一个字符开始测试
                position = begin + 1;
                begin = position;
                //回到树初始节点
                tempNode = rootNode;
            }else if(tempNode.isKeywordEnd()){
                //发现敏感词，从begin到position的位置用replacement代替
                result.append(replacement);
                position = position+1;
                begin = position;
                tempNode = rootNode;
            } else{
                position++;
            }
        }
        result.append(text.substring(begin));
        return result.toString();
    }
    //增加关键词
    private void addWord(String lineText){
        TrieNode tempNode  = rootNode;
        for (int i = 0; i < lineText.length(); i++) {
            char c = lineText.charAt(i);
            //过滤空格
            if(isSymbol(c)){
                continue;
            }
            TrieNode node = tempNode.getSubNode(c);
            if(node == null){
                node = new TrieNode();
                tempNode.addSubNode(c,node);
            }
            tempNode = node;
            if(i == lineText.length()-1){
                //关键词结束，设置结束标志
                tempNode.setKeywordEnd(true);
            }
        }
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        rootNode = new TrieNode();

        try {
            InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("\"SensitiveWords.txt");
            InputStreamReader read = new InputStreamReader(is);
            BufferedReader bufferedReader = new BufferedReader(read);
            String lineTxt;
            while ((lineTxt = bufferedReader.readLine())!=null){
                lineTxt = lineTxt.trim();
                addWord(lineTxt);
            }
            read.close();
        } catch (IOException e) {
            logger.error("读取敏感词文件失败" + e.getMessage());
        }

    }
    public static void main(String[] argv) {
        SensitiveService s = new SensitiveService();
        s.addWord("色情");
        s.addWord("好色");
        System.out.print(s.filter("你好色**情XX"));
    }
}