java – 将ImageOutputStream转换为byte []

一直在尝试使用JAI将ImageOutputStream转换为byte []一段时间.任何投入都表示赞赏.谢谢.

对不起,这是代码片段,我正在努力.我不得不提前发布.我面临的问题是,我能够从ImageOutputStream获取ByteArrayOutputStream.但它总是给我零字节.但是如果我使用FileOutputStream而不是ByteArrayOuputStream,我可以写入一个非零字节的文件. ：

File file = new File("C:/TIFFImages/tiff-image.tiff");
FileInputStream in = new FileInputStream(file);
long filelength = file.length();
byte[] bytes = new byte[(int)filelength]; 
int offset = 0; 
int numRead = 0; 

while (offset < bytes.length && (numRead=in.read(bytes, offset, bytes.length-offset)) >= 0) { 
    offset += numRead; 
} 
if (offset < bytes.length) { 
    throw new IOException("Could not completely read file "+file.getName()); 
} 

ByteArrayInputStream bais = new ByteArrayInputStream(bytes);

RenderedImage src = JAI.create("stream", SeekableStream.wrapInputStream(bais, true));
RenderedOp renderedOp = MedianFilterDescriptor.create(src, MedianFilterDescriptor.MEDIAN_MASK_SQUARE , 1, null);
BufferedImage image = renderedOp.getAsBufferedImage();

ByteArrayOutputStream baos = new ByteArrayOutputStream();

ImageOutputStream  ios =  ImageIO.createImageOutputStream(baos);
//Instead of baos if I pass a FileOutputStream to the above function. It writes non zero
//bytes to the output file

TIFFImageWriterSpi tiffspi = new TIFFImageWriterSpi();
ImageWriter writer = tiffspi.createWriterInstance();
RenderedImage renderedImage = PlanarImage.wrapRenderedImage(src);
writer.setOutput(ios);
writer.write(image);
writer.write(null,new IIOImage(image, null, null), param);

System.out.println("After tiff ImageIO operations" + baos.toByteArray().length);

谢谢 ,
 维奈

解决方法:

使用ByteArrayOutputStream(而不是FileOutputStream)创建ImageOutputStream

ByteArrayOutputStream bos = new ByteArrayOutputStream(255);
ImageOutputStream ios = ImageIO.createImageOutputStream(bos);
// use "ios" for image processing

完成图像处理后,图像字节将在“ios”对象中可用,但偏移量将位于“ios”对象的末尾.因此,我们需要将偏移量定位到“ios”对象的开头,然后读取字节以写入新的ByteArrayOutputStream对象.最后从新对象返回toByteArray().如下所示：

        public byte[] getBytes(ImageOutputStream ios) {
            ByteArrayOutputStream bos = new ByteArrayOutputStream(255);
            byte imageByte;
            long counter = 0; 
            try {
                    System.out.println("getStreamPosition()[BEFORE]=" + ios.getStreamPosition());
                    ios.seek(0);
                    System.out.println("getStreamPosition()[AFTER]=" + ios.getStreamPosition());
            } catch (IOException e1) {                       
                    e1.printStackTrace();
            }

            while (true) {
                    try {
                            bos.write(ios.readByte());
                            counter++;
                    } catch (EOFException e) {
                            System.out.println("End of Image Stream");
                            break;
                    } catch (IOException e) {
                            System.out.println("Error processing the Image Stream");
                            break;
                    }
            }
            System.out.println("Total bytes read=" + counter);
            byte[] retValue = bos.toByteArray();
            return retValue;
    }

标签：java,image,jai
来源： https://codeday.me/bug/20190610/1212860.html