我想更改多页TIFF图像的高度，所以我在下面的代码段中进行缩放。但是它仅从tiff文件返回第一页，我想它会将其转换为JPEG图像。如何保留文件的所有页面？

public static byte[] scale(byte[] fileData, int width, int height) {
  System.out.println("width:::"+width+"::::height:::"+height);
  ByteArrayInputStream in = new ByteArrayInputStream(fileData);
  ByteArrayOutputStream buffer=null;
  BufferedImage img=null;
  BufferedImage imageBuff=null;
  try {
    ImageInputStream imageStream = ImageIO.createImageInputStream(new ByteArrayInputStream(fileData));

    java.util.Iterator<ImageReader> readers = ImageIO.getImageReaders(imageStream); 
    while(readers.hasNext()) {  
      ImageReader nextImageReader = readers.next();  
      nextImageReader.reset();  
    }

    img = ImageIO.read(in);
    if(height == 0) {
      height = (width * img.getHeight())/ img.getWidth(); 
    }
    if(width == 0) {
      width = (height * img.getWidth())/ img.getHeight();
    }
    Image scaledImage = img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
    imageBuff = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    imageBuff.getGraphics().drawImage(scaledImage, 0, 0, new Color(0,0,0), null);

    buffer = new ByteArrayOutputStream();

    ImageIO.write(imageBuff, "TIF", buffer);


  } catch (IOException e) {
    e.printStackTrace();
  } finally{
    if(img!=null){
      img.flush();
      img=null;
    }
    if(imageBuff!=null){
      imageBuff.flush();
      imageBuff=null;
    }

    if(buffer!=null){
      try {
        buffer.close();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }

    if(in!=null){
      try {
        in.close();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    }
  }
  return buffer.toByteArray();
}

更新的代码：

public static byte[] resize(byte[] img,int height,int width) throws IOException {
        byte[] outimage = null;

        ImageReader reader=null;
        ImageWriter writer=null;
        ByteArrayOutputStream baos=null;
        ImageOutputStream ios=null;
        ImageInputStream imageStream=null;
        try {
            baos = new ByteArrayOutputStream(30000);
            ios = ImageIO.createImageOutputStream(baos);

            reader = getTiffImageReader();
            imageStream= ImageIO.createImageInputStream(new ByteArrayInputStream(img));
            reader.setInput(imageStream);

            int pages = reader.getNumImages(true);

            Iterator<ImageWriter> imageWriters = ImageIO.getImageWritersByFormatName("TIFF");
            writer = imageWriters.next();

            writer.setOutput(ios);
            ImageWriteParam writeParam = writer.getDefaultWriteParam();
            writeParam.setTilingMode(ImageWriteParam.MODE_DEFAULT);

            writer.prepareWriteSequence(reader.getStreamMetadata());

            for (int i = 0; i < pages; i++) {
                //IIOImage iioImage = reader.readAll(i, null);
                BufferedImage bufimage=null;
                BufferedImage imageBuff=null;
                bufimage=reader.read(i);
                imageBuff=Thumbnails.of(bufimage).size(1200, 1200).asBufferedImage();
                IIOImage scalediioImage = new IIOImage(imageBuff, null, null);
                writer.writeToSequence(scalediioImage, writeParam);
                bufimage.flush();
                imageBuff.flush();
            }

            writer.endWriteSequence();
            outimage = baos.toByteArray();


        } catch (Exception e) {
            e.printStackTrace();
        }
        finally{
                if(imageStream!=null){
                    imageStream.close();
                    }
                if(ios!=null){
                    ios.flush();
                    ios.close();
                    }

                if(baos!=null){
                    baos.close();
                }
                if(reader!=null){
                     reader.dispose();
                }
                if(writer!=null){
                    writer.dispose();
                }
            }
        return outimage;
    }