JAI关闭文件处理得太早？ [英] Is JAI closing file handles too early?

问题描述

我使用JAI来读取java中的Tiff文件。
与此代码：

  RenderedOp renderer = JAI.create（fileload，tifFilename）; 
 return renderer.getAsBufferedImage（）; 
  

使用java 7在一个框中工作良好，但在其他人使用java 8时， p>

 引起：com.sun.media.jai.codecimpl.util.ImagingException 
 at com.sun.media.jai .codecimpl.ImagingListenerProxy.errorOccurred（ImagingListenerProxy.java:63）
 at com.sun.media.jai.codecimpl.TIFFImage.getTile（TIFFImage.java:1087）
 at javax.media.jai.RenderedImageAdapter .getTile（RenderedImageAdapter.java:148）
 at javax.media.jai.NullOpImage.computeTile（NullOpImage.java:162）
 at com.sun.media.jai.util.SunTileScheduler.scheduleTile（SunTileScheduler .java：904）
 at javax.media.jai.OpImage.getTile（OpImage.java:1129）
 at javax.media.jai.PlanarImage.copyData（PlanarImage.java:2343）
在javax.media.jai.RenderedImageAdapter.copyData（RenderedImageAdapter.java:163）
 at javax.media.jai.RenderedOp.copyData（RenderedOp.java:2299）
 at javax.media.jai。 PlanarImage.getAsBufferedImage（PlanarImage.ja va：2525）
 at javax.media.jai.PlanarImage.getAsBufferedImage（PlanarImage.java:2546）
 at ... 
由com.sun.media.jai.codecimpl引起。 util.ImagingException：读取TIFF图像数据时发生IOException。 
 ... 17 more 
导致：java.io.IOException：流已关闭$ b $ at java.io.RandomAccessFile.seek0（Native Method）$ b $ at java.io.RandomAccessFile .seek（RandomAccessFile.java:557）
 at com.sun.media.jai.codec.FileSeekableStream.read（FileSeekableStream.java:168）
 at com.sun.media.jai.codec.SeekableStream .readFully（SeekableStream.java:318）
 at com.sun.media.jai.codecimpl.TIFFImage.getTile（TIFFImage.java:1081）
 ... 16 more 
  
 
 
  try（SeekableStream seekableStream = new FileSeekableStream（filename））{
 TIFFDecodeParam param = null; 
 ImageDecoder dec = ImageCodec.createImageDecoder（tiff，seekableStream，param）; 
 //如果需要，转换为缓冲图像
返回新RenderedImageAdapter（dec.decodeAsRenderedImage（））。getAsBufferedImage（）; //转换为缓冲图像
} 
  
并且问题似乎消失了。我的猜测是因为 FileSeekableStream s 不会过早收集，因为它的句柄仍保留在本地变量作用域中。也许还有其他的JAI方法可以做到这一点，只要确保在inputstream [？] 
 
 
 
上保持自己的句柄（帮助我发现这项工作：  RenderedImage to BufferedImage for multipage-tiff reading ） 
 
 
也<一个href =https://stackoverflow.com/questions/18517463/jai-create-seems-to-leave-file-descriptors-open> JAI创建似乎离开文件描述符打开 
 
 
 
不确定是否也适用于其他图片格式 
I'm using JAI to read Tiff files in java. 
with this code:
RenderedOp renderer = JAI.create("fileload", tifFilename);
return renderer.getAsBufferedImage();
Worked fine on one box with java 7, but on others with java 8, get this:
Caused by: com.sun.media.jai.codecimpl.util.ImagingException
    at com.sun.media.jai.codecimpl.ImagingListenerProxy.errorOccurred(ImagingListenerProxy.java:63)
    at com.sun.media.jai.codecimpl.TIFFImage.getTile(TIFFImage.java:1087)
    at javax.media.jai.RenderedImageAdapter.getTile(RenderedImageAdapter.java:148)
    at javax.media.jai.NullOpImage.computeTile(NullOpImage.java:162)
    at com.sun.media.jai.util.SunTileScheduler.scheduleTile(SunTileScheduler.java:904)
    at javax.media.jai.OpImage.getTile(OpImage.java:1129)
    at javax.media.jai.PlanarImage.copyData(PlanarImage.java:2343)
    at javax.media.jai.RenderedImageAdapter.copyData(RenderedImageAdapter.java:163)
    at javax.media.jai.RenderedOp.copyData(RenderedOp.java:2299)
    at javax.media.jai.PlanarImage.getAsBufferedImage(PlanarImage.java:2525)
    at javax.media.jai.PlanarImage.getAsBufferedImage(PlanarImage.java:2546)
    at  ...
Caused by: com.sun.media.jai.codecimpl.util.ImagingException: IOException occured while reading TIFF image data.
    ... 17 more
Caused by: java.io.IOException: Stream Closed
    at java.io.RandomAccessFile.seek0(Native Method)
    at java.io.RandomAccessFile.seek(RandomAccessFile.java:557)
    at com.sun.media.jai.codec.FileSeekableStream.read(FileSeekableStream.java:168)
    at com.sun.media.jai.codec.SeekableStream.readFully(SeekableStream.java:318)
    at com.sun.media.jai.codecimpl.TIFFImage.getTile(TIFFImage.java:1081)
    ... 16 more

解决方案
My theory is that garbage collection was kicking in and finalizing something it shouldn't.  very weird.  replacing it with this:
try (SeekableStream seekableStream = new FileSeekableStream(filename)){
  TIFFDecodeParam param = null;
  ImageDecoder dec = ImageCodec.createImageDecoder("tiff", seekableStream, param);
  // convert to buffered image if desired
  return new RenderedImageAdapter(dec.decodeAsRenderedImage()).getAsBufferedImage(); // convert to buffered image
}
and the problem seems to go away.  My guess is because the FileSeekableStream s is not prematurely collected since a handle to it remains in the local variable scope.  There are probably other JAI ways to do this as well, just make sure to keep your own handle on the inputstream [?]

related (helped me discover this work around: RenderedImage to BufferedImage for multipage-tiff reading)

also JAI create seems to leave file descriptors open

not sure if also applies to other image formats

                        
这篇关于JAI关闭文件处理得太早？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！