code: public static boolean isFileExist(final String filePathString) throws Exception {
  
          File f = new File(filePathString);
          return f.exists();
      }
docs: @param filePathString
  
  @return boolean
  
  @throws Exception
  @Description: 文件或目录是否存在
  @author liaoqiqi
  @date 2013-6-13