源代碼1：        InputStream in = new FileInputStream("E:\\java編程思想.jpg");        byte[] data = new byte[in.available()];        in.read(data);源代碼2：        InputStream in = new FileInputStream("E:\\java編程思想.jpg");        ByteArrayOutputStream output = new ByteArrayOutputStream();        byte[] data = null;        byte[] buf = new byte[1024];        int numBytesRead = 0;        while ((numBytesRead = in.read(buf)) != -1) {            output.write(buf, 0, numBytesRead);        }        data = output.toByteArray();以上兩個程序有什么性能上的區別嗎？