java 不改变尺寸大小对图片压缩

public ByteArrayInputStream compressImg(InputStream inputStream) {
     ByteArrayOutputStream baos = null;
     try {
         baos = new ByteArrayOutputStream();           Thumbnails.of(inputStream).scale(0.25f).outputQuality(0.5f).toOutputStream(baos);
         if (baos != null)
             return parse(baos);
     } catch (Exception e) {
         e.printStackTrace();
     }
     return null;
 }
 也可以按照具体的尺寸来进行压缩、旋转、裁剪等
//指定大小进行缩放
 Thumbnails.of(inputStream).size(200, 300).toFile("C:/image_200x300.jpg");
//不按照比例，指定大小进行缩放 keepAspectRatio(false) 默认是按照比例缩放的
 Thumbnails.of(inputStream).size(120, 120).keepAspectRatio(false).toFile("C:/image_120x120.jpg");
 
 //旋转 rotate(角度),正数：顺时针 负数：逆时针
 Thumbnails.of("images/test.jpg").size(1280, 1024).rotate(90).toFile("C:/image+90.jpg");
//水印 watermark(位置，水印图，透明度)
 Thumbnails.of("images/test.jpg").size(1280, 1024).watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("images/watermark.png")), 0.5f).outputQuality(0.8f).toFile("C:/image_watermark_bottom_right.jpg");
//转化图片格式
 Thumbnails.of("images/test.jpg").size(1280, 1024).outputFormat("png").toFile("C:/image_1280x1024.png");
//裁剪
 /**
  * 图片中心400*400的区域
  */
 Thumbnails.of("images/test.jpg").sourceRegion(Positions.CENTER, 400, 400).size(200, 200).keepAspectRatio(false)
         .toFile("C:/image_region_center.jpg");
 /**
  * 图片右下400*400的区域
  */
 Thumbnails.of("images/test.jpg").sourceRegion(Positions.BOTTOM_RIGHT, 400, 400).size(200, 200).keepAspectRatio(false)
         .toFile("C:/image_region_bootom_right.jpg");
 /**
  * 指定坐标
  */
 Thumbnails.of("images/test.jpg").sourceRegion(600, 500, 400, 400).size(200, 200).keepAspectRatio(false).toFile("C:/image_region_coord.jpg");
 
 2.1按照指定的width，height进行缩放
/**
 *@param scale  width,height的缩放比例
 *@param suffix 文件格式，pdf，jpg
 **/
 public ByteArrayInputStream scaleImage(InputStream inputStream, double scale, String suffix) {
     BufferedImage bufferedImage;
     try {
         bufferedImage = ImageIO.read(inputStream);
         int width = bufferedImage.getWidth();
         int height = bufferedImage.getHeight();
        width = parseDoubleToInt(width * scale);
         height = parseDoubleToInt(height * scale);
        Image image = bufferedImage.getScaledInstance(width, height,
                 Image.SCALE_SMOOTH);
        BufferedImage outputImage = new BufferedImage(width, height,
                 BufferedImage.TYPE_INT_RGB);
         Graphics graphics = outputImage.getGraphics();
         graphics.drawImage(image, 0, 0, null);
         graphics.dispose();
         ByteArrayOutputStream bs = new ByteArrayOutputStream();
         ImageOutputStream imOut = ImageIO.createImageOutputStream(bs);
         ImageIO.write(bufferedImage, suffix, imOut);
         return new ByteArrayInputStream(bs.toByteArray());
     } catch (IOException e) {
         e.printStackTrace();
     }
     return null;
 }
 2.2 直接指定压缩程度来进行压缩
/**
 *@param qality 压缩的程度
 *@param suffix 文件格式，pdf，jpg
 **/
 public ByteArrayInputStream scaleImage(InputStream inputStream, float qality, String suffix) {
     BufferedImage bufferedImage;
     ByteArrayOutputStream out = new ByteArrayOutputStream();
     ImageWriter imgWriter;
     ImageWriteParam imgWriteParams;
     try {
         bufferedImage = ImageIO.read(inputStream);
         imgWriter = ImageIO.getImageWritersByFormatName(suffix).next();
         imgWriteParams = new JPEGImageWriteParam(null);
         // 要使用压缩，必须指定压缩方式为MODE_EXPLICIT
         imgWriteParams.setCompressionMode(imgWriteParams.MODE_EXPLICIT);
         // 这里指定压缩的程度，参数qality是取值0~1范围内，
         imgWriteParams.setCompressionQuality(qality);
         imgWriteParams.setProgressiveMode(imgWriteParams.MODE_DISABLED);
         ColorModel colorModel = bufferedImage.getColorModel();// ColorModel.getRGBdefault();
         imgWriteParams.setDestinationType(new ImageTypeSpecifier(colorModel, colorModel.createCompatibleSampleModel(32, 32)));
         imgWriter.reset();
         // OutputStream构造
         imgWriter.setOutput(ImageIO.createImageOutputStream(out));
         imgWriter.write(null, new IIOImage(bufferedImage, null, null), imgWriteParams);
         return new ByteArrayInputStream(out.toByteArray());
     } catch (IOException e) {
         e.printStackTrace();
     }
     return null;
 }

/**
 * 压缩图片
 *
 * @param bufferedImage BufferedImage对象
 * @param quality       压缩的程度（0-1越小压缩的比列越大）
 * @param suffix        后缀
 * @return ByteArrayOutputStream
 */
public static ByteArrayOutputStream scale(BufferedImage bufferedImage, double quality, String suffix) {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    try {
        Thumbnails.of(bufferedImage).scale(1f).outputQuality(quality).outputFormat(suffix).toOutputStream(out);
        try {
            out.close();
        } catch (IOException e) {
            log.error("关闭输出流失败{}", e.getMessage());
        }
    } catch (IOException e) {
        log.error("压缩图片处理失败{}", e.getMessage());
    }
    return out;
}