Java使用DFA算法实现过滤多家公司自定义敏感字功能详解

背景

因为最近有通讯有个需求，说需要让多家客户公司可以自定义敏感词过滤掉他们自定义的规则，选择了DFA算法来做，不过和以前传统了DFA写法不太一样了

模式图

直接上代码

publicclassKeywordFilter {
//  private static ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
  publicstaticMap currentMap =newConcurrentHashMap();
  publicstaticMap nowhash =null;
  publicstaticObject wordMap;// map子节点
  // 不建立对象
  privateKeywordFilter() {
  }
  privatestaticString getKey(intcompanyId) {
    return"companyId"+ companyId;
  }
  /*
   * 
说明:清扫内容
   *
   * @author:姚旭民
   *
   * @data:2017-8-22 上午10:13:11
   */
  public static void clear() {
    try {
      currentMap.clear();
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
    }
  }
  /*
   * 
说明:各个渠道的过滤字符
   *
   * @author:姚旭民
   *
   * @data:2017-8-20 下午2:55:06
   */
  public static void saveKeywords(int companyId, List keywords) {
    try {
      Map tempAllMap = currentMap;
      String key = getKey(companyId);
      int l = keywords.size();
      int il;
      Map tempMap;
      for (int i = 0; i  newWordHash = new HashMap();
            newWordHash.put(key, "0");
            nowhash.put(word, newWordHash);
            nowhash = newWordHash;
          }
          if (j == il - 1) {
            nowhash.put(key, "1");
          }
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      nowhash = null;
      wordMap = null;
    }
  }
  /*
   * 
说明:替换掉对应的渠道规定掉敏感字
   *
   * @author:姚旭民
   *
   * @data:2017-8-20 上午11:41:47
   */
  public static List repword(int companyId, String txt) {
    Map tempMap = currentMap;
    List result = new ArrayList();
    String key = getKey(companyId);
    nowhash = currentMap;
    int l = txt.length();
    char word;
    String keywordStr = "";
    String keyStatu;
    StringBuilder keyword = new StringBuilder();// 敏感字
    for (int i = 0; i  0 ? keywordStr.substring(0,
        keywordStr.length() - 1) : keywordStr);
    return result;
  }
  /*
   * 
说明:检查是否存在敏感字
   *
   * @author:姚旭民
   *
   * @data:2017-8-20 下午3:00:06 专门设计成私有的，如果没有理由，别改动他
   */
  private static int checkKeyWords(String txt, int companyId, int begin) {
    int result = 0;
    String key = getKey(companyId);
    try {
      nowhash = currentMap;
      int l = txt.length();
      char word = 0;
      for (int i = begin; i 说明:返回检查的文本中包含的敏感字
   *
   * @author:姚旭民
   *
   * @data:2017-8-20 下午3:32:53
   */
  public static String getTxtKeyWords(String txt, int companyId) {
    String result = null;
    StringBuilder temp = new StringBuilder();
    String key;
    int l = txt.length();
    for (int i = 0; i  0) {
        key = (txt.substring(i, i + len));// 挑选出来的关键字
        temp.append(key + ",");
        txt = txt.replaceAll(key, "");// 挑选出来的关键字替换成空白，加快挑选速度
        l = txt.length();
      } else {
        i++;
      }
    }
    if (temp.length() > 0) {
      result = temp.substring(0, temp.length() - 1);
    }
    return result;
  }
  /*
   * 
说明:判断文中是否包含渠道规定的敏感字
   *
   * @author:姚旭民
   *
   * @data:2017-8-20 下午3:33:19
   */
  publicbooleanisKeyWords(String txt,intcompanyId) {
    for(inti =0; i 0) {
        returntrue;
      }
    }
    returnfalse;
  }
  publicstaticvoidmain(String[] arg) {
    List keywords =newArrayList();
    keywords.add("傻×");
    keywords.add("汉奸");
    keywords.add("草");
    keywords.add("草泥马");
    KeywordFilter.saveKeywords(1, keywords);
    String txt ="是傻×汉奸傻A傻B傻C傻D汉奸傻×草泥马";
    List list = repword(1, txt);
    System.out.println("文中包含的敏感字为:"+ list.get(1));
    System.out.println("原文:"+ txt);
    System.out.println("敏感字过滤后:"+ list.get(0));
  }
}