读取文件到byte数组中

public byte[] byteArray(String fileName)
    {
      InputStream is = fileName.getClass().getResourceAsStream(fileName);
      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      try
      {
        int ch = 0;
        while ((ch = is.read()) != -1)
        {
          baos.write(ch);
        }
        baos.close();
        is.close();
      }
      catch (IOException ex)
      {
      }
      return baos.toByteArray();
    }