将 ImageOutputStream 转换为 byte[]

Question

一直在尝试使用 JAI 将 ImageOutputStream 转换为 byte[] 一段时间。任何输入表示赞赏。谢谢。

抱歉，这是代码片段，我正在处理。我不得不提前发布它。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

Answer 1

我得到了答案，这与 Guillaume 的建议非常接近。除了不需要写入中间的临时文件。以下是将 ImageOutputStream 转换为 byte[] 的修改代码：

ByteArrayOutputStream baos = new ByteArrayOutputStream(37628);
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);

//Create a ByteArrayInputStream to read that ByteArrayOutputStream and read it from ImageIO

ByteArrayInputStream bai = new ByteArrayInputStream(baos.toByteArray());
RenderedImage out = ImageIO.read(bai);
int size = bos.toByteArray().length;

System.out.println(""+ size);

return bos.toByteArray

Answer 2

我很确定这是因为您没有ImageOutputStream.flush()在操作结束时调用 - 如果创建的 IOS 是 a MemoryCacheOutputStream，则似乎需要对某些 ​​ImageIO 实现进行显式刷新。