小数组拷贝

            write(byte[] b)

            write(byte[] b, int off, int len)写出有效的字节个数

案例：

           FileInputStream fis = new FileInStream("文件1.mp3");

           FileOutputStream  fos = new FileOutputStream("Copy.mp3");

           byte[] arr = new byte[1024 * 8];

           int len;

           while((len = fis.read(arr)) != -1) {

                   fos.write(arr, 0, len);

}

           fis.close;

           fos.close;