在java中将图像转换为二进制数据(0和1)

Question

我想从URL读取图像并将其转换为二进制数据.请帮我..

        byte[] data = null;
        ByteArrayOutputStream bas = null;
        try {
            URL u = new URL(
                    "http://www.eso.org/public/archives/images/screen/eso0844a.jpg");
            HttpURLConnection con1 = (HttpURLConnection) u.openConnection();
            con1.setAllowUserInteraction(true);
            con1.setRequestMethod("GET");
            con1.connect();
            InputStream is = con1.getInputStream();
            BufferedImage imgToServe = null;
            if (is != null) {
                imgToServe = ImageIO.read(is);
            }
            bas = new ByteArrayOutputStream();
            ImageIO.write(imgToServe, "jpg", bas);

            File f = new File("C:\\img.jpg");
            ImageIO.write(imgToServe, "jpg", f);

            data = bas.toByteArray();
            String str = "";
            for (int i = 0; i < data.length; i++) {
                str = str + toBinary(data[i]);
            }
            System.out.println(str);

        } catch (HTTPException he) {

        } catch (IOException ioe) {
        }
    }

    private static String toBinary(byte b) {
        StringBuilder sb = new StringBuilder("00000000");

        for (int bit = 0; bit < 8; bit++) {
            if (((b >> bit) & 1) > 0) {
                sb.setCharAt(7 - bit, '1');
            }
        }
        return (sb.toString());
    }

Answer 1

如果您正在从URL读取图像,它将已经是二进制格式.只需下载数据并忽略它是图像的事实.毕竟,参与下载的代码无关紧要.假设您要将其写入文件或类似文件,只需打开URLConnection并打开FileOutputStream,然后重复读取来自Web的输入流,将您读取的数据写入输出流.

如果那不是您所追求的,请澄清问题.

编辑:如果你真的想把数据作为单独的位(这对我来说有点奇怪)你应该将问题分成两部分:

• 下载数据(见上文;如果您不需要它在磁盘上,请考虑写入a ByteArrayOutputStream)
• 将任意二进制数据(字节数组或输入流)转换为0和1

你如何处理后一项任务将取决于你实际想要做什么.这里的真正目的是什么？

Answer 2

您可以使用此标准ImageIO.该read方法采用a URL并将其检索到Image.然后,您可以使用该write方法将其写入a File或类似的情况,a ByteArrayOutputStream将图像输出到内存缓冲区.

public static void main(String[] args) throws Exception {

    // read "any" type of image (in this case a png file)
    BufferedImage image = ImageIO.read(new URL("http://upload.wikimedia.org/wikipedia/en/2/24/Lenna.png"));

    // write it to byte array in-memory (jpg format)
    ByteArrayOutputStream b = new ByteArrayOutputStream();
    ImageIO.write(image, "jpg", b);

    // do whatever with the array...
    byte[] jpgByteArray = b.toByteArray();

    // convert it to a String with 0s and 1s        
    StringBuilder sb = new StringBuilder();
    for (byte by : jpgByteArray)
        sb.append(Integer.toBinaryString(by & 0xFF));

    System.out.println(sb.toString());
}