code: private static String irregularity(String word){
          if(Character.isDigit(word.charAt(0))){
              LOGGER.debug("词以数字开头，忽略："+word);
              return null;
          }
          if(word.startsWith("0x")
                  || word.startsWith("0X")){
              LOGGER.debug("词为16进制，忽略："+word);
              return null;
          }
          if(word.endsWith("l")
                  && isNumeric(word.substring(0, word.length()-1))){
              LOGGER.debug("词为long类型数字，忽略："+word);
              return null;
          }
          if(UNICODE.matcher(word).find()){
              LOGGER.debug("词为UNICODE字符编码，忽略："+word);
              return null;
          }
          switch (word){
              //I’ll do it. You'll see.
              case "ll": return "will";
              //If you’re already building applications using Spring.
              case "re": return "are";
              //package com.manning.sdmia.ch04;
              case "ch": return "chapter";
              //you find you’ve made a
              case "ve": return "have";
              //but it doesn’t stop there.
              case "doesn": return "does";
              //but it isn’t enough.
              case "isn": return "is";
              //<input type="text" name="firstName" /><br/>
              case "br": return null;
          }
          return word;
      }
docs: 处理分词意外，即无规则情况
  @param word
  @return