如何在Java中将BuffereImage保存到FastDFS？

我有一个图像，我用它做了一些事情，最后我得到了一个BuffereImage对象（原始图像的子图像），现在我想将子图像保存到FastDFS而不保存在本地，我该怎么办

我已经将子映像作为文件保存到本地，但我不想这样做，因为这样会造成浪费

    String oriPicPathInFastDFS = "http://127.0.0.1/xx/xx/xx/xx";
    BufferedImage image = null;
    try {
        image = ImageIO.read(new URL(oriPicPathInFastDFS));
    } catch (IOException e) {
        e.printStackTrace();
    }

    // do something

    // this is the sub image that I want to save to FastDFS
    BufferedImage subImage = image.getSubimage(5, 5, 5, 5);

    // these code can save the sub image to my local and then upload to fastDFS
    String localPath = "/home/xx/x/xx.jpg";
    File detectionFile = new File(localPath);
    try {
        detectionFile.createNewFile();
        ImageIO.write(subImage, "jpg", detectionFile);
    } catch (IOException e) {
        e.printStackTrace();
    }

    // upload to fast dfs

---

我想将子映像上载到fastDFS，而不将其保存到本地。

好的，我找到了解决此问题的方法

    // change the BufferedImage to byte[]
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    try {
        boolean flag = ImageIO.write(sunImage, "jpg", out);
    } catch (IOException e) {
        e.printStackTrace();
    }
    byte[] byteArray = out.toByteArray();

    // then save the byteArray to fast DFS