Java get image extension/type using BufferedImage from URL

Question

I am familiar with working with images. I retrieve/read an image from a URL, where the URL does not have a file extension. Then I wish to write/save the image to the local s

Answer 1

If you get the image from a URL, that means you can access the image through an InputStream. From that you can use ImageIO to get the image type (format) and with the following code, create a BufferedImage at the same time.

public static BufferedImageWrapper getImageAndTypeFromInputStream(InputStream is) {

    String format = null;
    BufferedImage bufferedimage = null;
    try (ImageInputStream iis = ImageIO.createImageInputStream(is);) {

      Iterator readers = ImageIO.getImageReaders(iis);

      if (readers.hasNext()) {

        ImageReader reader = readers.next();
        format = reader.getFormatName();
        reader.setInput(iis);
        bufferedimage = reader.read(0);
      }
    } catch (IOException e) {
      logger.error("ERROR DETERMINING IMAGE TYPE!!!", e);
    }

    return new BufferedImageWrapper(format, bufferedimage);
  }

  public static class BufferedImageWrapper {

    private final String imageType;
    private final BufferedImage bufferedimage;

    /**
     * Constructor
     *
     * @param imageType
     * @param bufferedimage
     */
    public BufferedImageWrapper(String imageType, BufferedImage bufferedimage) {
      this.imageType = imageType;
      this.bufferedimage = bufferedimage;
    }

    public String getImageType() {

      return imageType;
    }

    public BufferedImage getBufferedimage() {

      return bufferedimage;
    }

  }