敏感词过滤的实现方案

1.采用DFA算法实现

/**
 * 敏感词过滤工具类
 *
 * @author maple
 */
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
 
@SuppressWarnings({"unchecked", "rawtypes"})
public class SensitiveFilterUtil {
    /**
     * 敏感词集合
     */
    public static HashMap sensitiveWordMap;
 
    /**
     * 初始化敏感词库,构建DFA算法模型
     */
    public static void initContext(HashSet<String> set) {
        initSensitiveWordMap(set);
    }
 
    /**
     * 初始化敏感词库,构建DFA算法模型
     *
     * @param sensitiveWordSet 敏感词库
     */
    private static void initSensitiveWordMap(Set<String> sensitiveWordSet) {
        //初始化敏感词容器,减少扩容操作
        sensitiveWordMap = new HashMap<String, String>(sensitiveWordSet.size());
        Map<Object, Object> temp;
        Map<Object, Object> newWorMap;
        //遍历sensitiveWordSet
        for (String key : sensitiveWordSet) {
            temp = sensitiveWordMap;
            for (int i = 0; i < key.length(); i++) {
                //转换成char型
                char keyChar = key.charAt(i);
                //库中获取关键字
                Object wordMap = temp.get(keyChar);
                //如果存在该key,直接赋值,用于下一个循环获取
                if (wordMap != null) {
                    temp = (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<>();
                    //不是最后一个
                    newWorMap.put("isEnd", "0");
                    temp.put(keyChar, newWorMap);
                    temp = newWorMap;
                }
                //最后一个
                if (i == key.length() - 1) temp.put("isEnd", "1");
            }
        }
    }
 
    /**
     * 判断文字是否包含敏感字符
     * <p>
     * 文本
     * <p>
     * 若包含返回true,否则返回false
     */
    public static boolean contains(String txt) {
        boolean flag = false;
        for (int i = 0; i < txt.length(); i++) {
            int matchFlag = checkSensitiveWord(txt, i); //判断是否包含敏感字符
            if (matchFlag > 0) {//大于0存在,返回true
                flag = true;
            }
        }
        return flag;
    }
 
    /**
     * 检查文字中是否包含敏感字符,检查规则如下:
     *
     * @param txt
     * @param beginIndex
     * @return 如果存在, 则返回敏感词字符的长度, 不存在返回0
     */
    private static int checkSensitiveWord(String txt, int beginIndex) {
        //敏感词结束标识位:用于敏感词只有1位的情况
        boolean flag = false;
        //匹配标识数默认为0
        int matchFlag = 0;
        char word;
        Map nowMap = sensitiveWordMap;
        for (int i = beginIndex; i < txt.length(); i++) {
            word = txt.charAt(i);
            //获取指定key
            nowMap = (Map) nowMap.get(word);
            if (nowMap != null) {//存在,则判断是否为最后一个
                //找到相应key,匹配标识+1
                matchFlag++;
                //如果为最后一个匹配规则,结束循环,返回匹配标识数
                if ("1".equals(nowMap.get("isEnd"))) {
                    //结束标志位为true
                    flag = true;
                }
            } 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;
    }
 
    /**
     * 获取文字中的敏感词
     * <p>
     * txt文字
     */
    public static HashSet getSensitiveWord(String txt) {
        HashSet hashSet = new HashSet();
        for (int i = 0; i < txt.length(); i++) {
            //判断是否包含敏感字符
            int length = checkSensitiveWord(txt, i);
            if (length > 0) {//存在,加入list中
                hashSet.add(txt.substring(i, i + length));
                i = i + length - 1;//减1的原因,是因为for会自增
            }
        }
        return hashSet;
    }
 
 
    /**
     * context是要校验的内容。返回结果是list，为空说明没有敏感词
     *
     * @param context
     * @return
     */
    public static HashSet checkTxt(String context, HashSet<String> set) {
        initContext(set);
        //包含敏感词返回所有敏感词数据
        return getSensitiveWord(context);
    }
}

2.违规词实体类

/**
 * 敏感词对象 disk_sensitive_word
 * 
 * @author maple
 * @date 2024-04-17
 */
public class DiskSensitiveWord extends BaseEntity
{
    private static final long serialVersionUID = 1L;
 
    /** 自增id */
    private Long id;
 
    /** 添加人 */
    @Excel(name = "添加人")
    private String userName;
 
    /** 敏感词 */
    @Excel(name = "敏感词")
    private String sensitiveWord;
 
    public void setId(Long id) 
    {
        this.id = id;
    }
 
    public Long getId() 
    {
        return id;
    }
    public void setUserName(String userName) 
    {
        this.userName = userName;
    }
 
    public String getUserName() 
    {
        return userName;
    }
    public void setSensitiveWord(String sensitiveWord) 
    {
        this.sensitiveWord = sensitiveWord;
    }
 
    public String getSensitiveWord() 
    {
        return sensitiveWord;
    }
 
    @Override
    public String toString() {
        return new ToStringBuilder(this,ToStringStyle.MULTI_LINE_STYLE)
            .append("id", getId())
            .append("userName", getUserName())
            .append("sensitiveWord", getSensitiveWord())
            .append("createTime", getCreateTime())
            .append("updateTime", getUpdateTime())
            .toString();
    }
}

3.测试用例，数据来源可以通过数据库，文件获取，有需要违规词库的联系我哈

        HashSet<String> set = this.selectDiskSensitiveWordAllList()
                .stream().map(DiskSensitiveWord::getSensitiveWord).collect(Collectors.toCollection(HashSet::new));
        HashSet hashSet = SensitiveFilterUtil.checkTxt(text, set);
        if (CollectionUtil.isEmpty(hashSet)) return false;
        throw new ServiceException("有敏感词 "+ hashSet);