java追加写文件（android）

•     private FileOutputStream fileOutputStream;
      private static final String FILENAME = "Hello";
   File file = new File(Environment.getExternalStorageDirectory()
                                  .getAbsolutePath(),FILENAME);
                          RandomAccessFile randomAccessFile = new RandomAccessFile(file,"rw");
                          randomAccessFile.seek(file.length());
                          randomAccessFile.writeBytes("hello,Kitty!!\r\n");
                          randomAccessFile.close();