springboot设置像素大小

public static BufferedImage scale(BufferedImage imageToScale, int dWidth, int dHeight) {
        BufferedImage scaledImage = null;
        if (imageToScale != null) {
            scaledImage = new BufferedImage(dWidth, dHeight, imageToScale.getType());
            Graphics2D graphics2D = scaledImage.createGraphics();
            graphics2D.drawImage(imageToScale, 0, 0, dWidth, dHeight, null);
            graphics2D.dispose();
        }
        return scaledImage;
    }

@Override
    public void save(String token, MultipartFile multipartFile) throws Exception {
        AvatarStoreRequest request = decodeToken(token);
        if (LocalDateTime.now().isAfter(request.getExpires())) {
            throw new BadRequestException("Token is expired!");
        }
        save(request, multipartFile.getInputStream(), multipartFile.getSize());
    }

    @Override //初始随机生成图片图片
    public void init(AvatarStoreRequest request) throws Exception {
        BufferedImage identicon = IdenticonGenerator.generateIdenticons(Objects.requireNonNull(md5Hex(request.getAvatarType().toString() + request.getEntityIdentifier().toLowerCase())), 128, 128);

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ImageIO.write(identicon, "png", byteArrayOutputStream);
        byte[] bytes = byteArrayOutputStream.toByteArray();
        ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
        save(request, inputStream, byteArrayOutputStream.size());
    }

//生成三张不同像素的图片
    private void save(AvatarStoreRequest request, InputStream imageInputStream, long imageSize) throws Exception {
        if (imageSize > imageConfig.getMaxAvatarUploadingFileSize()) {
            throw new BadRequestException("Uploaded file is too big!");
        }

        Path dirPath = getImageDir(request.getAvatarType(), request.getEntityId());
        if (!Files.exists(dirPath)) {
            Files.createDirectories(dirPath);
        }
        BufferedImage image = ImageIO.read(imageInputStream);
        // TODO: make sure the content type: multipartFile.getContentType()
        for (AvatarStoreRequest.Size size : imageConfig.getAvatarSizes()) {
            final String formatName = "png";
            Path filePath = getImagePath(request.getAvatarType(), request.getEntityId(), size, formatName);
            File outputFile = new File(filePath.toString());
            Files.deleteIfExists(filePath);
            if (image.getWidth() == size.getWidth() && image.getHeight() == size.getHeight()) {
                ImageIO.write(image, formatName, outputFile);
            } else {
                BufferedImage resizedImage = scale(image, size.getWidth(), size.getHeight());
                ImageIO.write(resizedImage, formatName, outputFile);
            }
        }
    }

//随机生成一张图片
    public static BufferedImage generateIdenticons(String text, int image_width, int image_height) {
        int width = 5, height = 5;

        byte[] hash = text.getBytes();

        BufferedImage identicon = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        WritableRaster raster = identicon.getRaster();

        int[] background = new int[]{255, 255, 255, 0};
        int[] foreground = new int[]{hash[0] & 255, hash[1] & 255, hash[2] & 255, 255};

        for (int x = 0; x < width; x++) {
            //Enforce horizontal symmetry
            int i = x < 3 ? x : 4 - x;
            for (int y = 0; y < height; y++) {
                int[] pixelColor;
                //toggle pixels based on bit being on/off
                if ((hash[i] >> y & 1) == 1)
                    pixelColor = foreground;
                else
                    pixelColor = background;
                raster.setPixel(x, y, pixelColor);
            }
        }

        BufferedImage finalImage = new BufferedImage(image_width, image_height, BufferedImage.TYPE_INT_ARGB);

        //Scale image to the size you want
        AffineTransform at = new AffineTransform();
        at.scale(image_width / width, image_height / height);
        AffineTransformOp op = new AffineTransformOp(at, AffineTransformOp.TYPE_NEAREST_NEIGHBOR);
        finalImage = op.filter(identicon, finalImage);

        return finalImage;
    }

    public static String hex(byte[] array) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < array.length; ++i) {
            sb.append(Integer.toHexString((array[i]
                    & 0xFF) | 0x100).substring(1, 3));
        }
        return sb.toString();
    }

    public static String md5Hex(String message) {
        try {
            MessageDigest md =
                    MessageDigest.getInstance("MD5");
            return hex(md.digest(message.getBytes("CP1252")));
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void saveImage(BufferedImage bufferedImage, String name) {
        File outputfile = new File(name + ".png");
        try {
            ImageIO.write(bufferedImage, "png", outputfile);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }