code: public static boolean isFraction(final String text, final int start, final int len){
          if(len < 3){
              return false;
          }
          int index = -1;
          for(int i=start; i<start+len; i++){
              char c = text.charAt(i);
              if(c=='.' || c=='/' || c=='／' || c=='．' || c=='·'){
                  index = i;
                  break;
              }
          }
          if(index == -1 || index == start || index == start+len-1){
              return false;
          }
          int beforeLen = index-start;
          return isNumber(text, start, beforeLen) && isNumber(text, index+1, len-(beforeLen+1));
      }
docs: 小数和分数识别
  @param text 识别文本
  @param start 待识别文本开始索引
  @param len 识别长度
  @return 是否识别