WebappClassLoader无法加载资源

时间:2016-11-09 13:27:00

标签: classloader dicom dcm4che

我有以下代码尝试读取Dicom图像:

public  BufferedImage readDicomFile(File dicomFile) {

    ImageReader reader = (ImageReader) ImageIO.getImageReadersByFormatName("DICOM").next();
    BufferedImage tempImage = null;
    try {
        if (!dicomFile.exists()) {          
            return null;
        }
        ImageIO.scanForPlugins();
        tempImage = ImageIO.read(dicomFile);            
        DicomObject obj = new DicomInputStream(dicomFile).readDicomObject();
        String overlayData = obj.getString(1610625024);
        if ((overlayData != null) && (overlayData.length() > 0)) {
            tempImage = combineImages(tempImage,
                    OverlayUtils.extractOverlay(obj, 1610625024, reader,
                            "FFFFFF"));
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return tempImage;
}

然而,这就是我所得到的:

SEVERE: java.lang.IllegalStateException: WEB9031: WebappClassLoader unable to load resource [org.dcm4che.data.DcmParserFactory], because it has not yet been started, or was already stopped
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1401)
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1359)
at org.dcm4cheri.imageio.plugins.DcmImageReaderSpi.canDecodeInput(DcmImageReaderSpi.java:113)
at javax.imageio.ImageIO$CanDecodeInputFilter.filter(ImageIO.java:567)
at javax.imageio.spi.FilterIterator.advance(ServiceRegistry.java:810)
at javax.imageio.spi.FilterIterator.<init>(ServiceRegistry.java:804)
at javax.imageio.spi.ServiceRegistry.getServiceProviders(ServiceRegistry.java:508)
at javax.imageio.ImageIO.getImageReaders(ImageIO.java:646)
at javax.imageio.ImageIO.read(ImageIO.java:1438)
at javax.imageio.ImageIO.read(ImageIO.java:1308)
at edu.kfshrc.dm.services.DicomViewerService.readDicomFile(DicomViewerService.java:565)
at edu.kfshrc.dm.services.DicomViewerService.extractImageFromDicom(DicomViewerService.java:414)
at edu.kfshrc.dm.servlet.DicomViewerServlet.doGet(DicomViewerServlet.java:131)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)

SEVERE:     at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1401)
SEVERE:     at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1359)
SEVERE:     at org.dcm4cheri.imageio.plugins.DcmImageReaderSpi.canDecodeInput(DcmImageReaderSpi.java:113)
SEVERE:     at javax.imageio.ImageIO$CanDecodeInputFilter.filter(ImageIO.java:567)
SEVERE:     at javax.imageio.spi.FilterIterator.advance(ServiceRegistry.java:810)
SEVERE:     at javax.imageio.spi.FilterIterator.<init>(ServiceRegistry.java:804)
SEVERE:     at javax.imageio.spi.ServiceRegistry.getServiceProviders(ServiceRegistry.java:508)
SEVERE:     at javax.imageio.ImageIO.getImageReaders(ImageIO.java:646)
SEVERE:     at javax.imageio.ImageIO.read(ImageIO.java:1438)
SEVERE:     at javax.imageio.ImageIO.read(ImageIO.java:1308)
SEVERE:     at edu.kfshrc.dm.services.DicomViewerService.readDicomFile(DicomViewerService.java:565)
SEVERE:     at edu.kfshrc.dm.services.DicomViewerService.extractImageFromDicom(DicomViewerService.java:414)
SEVERE:     at edu.kfshrc.dm.servlet.DicomViewerServlet.doGet(DicomViewerServlet.java:131)
SEVERE:     at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
SEVERE:     at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
SEVERE:     at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
SEVERE:     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
SEVERE:     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
SEVERE:     at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
SEVERE:     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
SEVERE:     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
SEVERE:     at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
SEVERE:     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
SEVERE:     at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
SEVERE:     at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
SEVERE:     at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
SEVERE:     at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
SEVERE:     at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
SEVERE:     at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
SEVERE:     at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
SEVERE:     at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
SEVERE:     at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
SEVERE:     at java.lang.Thread.run(Thread.java:722)

我正在传递一个指向某个路径的File对象:“c:\ temp2 \ testing.dcm”。当它到达试图读取Dicom文件的行时,它会给出上述错误。

你能帮忙吗?

1 个答案:

答案 0 :(得分:0)

Salam Wael,

问题的根本原因是Servlet容器(tomcat,..)无法自动处理注册/取消注册本机库

这意味着当dcm4che加载使用本机库的ImageIO DICOM插件时,它拥有该插件,如果你想从另一个webApp(Servlet)使用它,你必须再次扫描插件,以便每次执行dcm4che DICOM读写器代码

我建议在每次执行后自行取消注册本机ImageIO插件,以防止将来发生潜在的内存泄漏

     try{
ImageIO.scanForPlugins()
    //Dicom code
        }
    catch {
    //exceptions
    }
    finally {
                try {
                    // De-register any locally registered IIO plugins. Relies on
                    // each web app having its own context class loader.
                    final IIORegistry registry = IIORegistry.getDefaultInstance();
                    final LocalFilter localFilter = new LocalFilter(Thread.currentThread().getContextClassLoader()); 

                    // scanForPlugins uses context  class loader
                    Iterator<Class<?>> categories = registry.getCategories();

                    while (categories.hasNext()) {
                        Class<?> category = categories.next();
                        Iterator<?> providers = registry.getServiceProviders(category, localFilter, false);

                        // Copy the providers, as de-registering while iterating
                        // over providers will lead to
                        // ConcurrentModificationExceptions.
                        List<Object> providersCopy = new ArrayList<Object>();
                        while (providers.hasNext()) {
                            providersCopy.add(providers.next());
                        }

                        for (Object provider : providersCopy) {
                            registry.deregisterServiceProvider(provider);
                            log.debug(String.format("Unregistered locally installed provider class: %s",provider.getClass()));
                        }
                    }
                } catch (Exception ex) {
                    _logger.error("Exception occured while de-registering locally registered IIO plugins", ex);
                }
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