我正在尝试编写一个 WebApplication 来查看一些 DICOM 文件。我的想法是通过调用我的 servlet 将 DICOM 文件即时转换为 JPEG。我使用 dcm4che 2.0.27 来转换文件。
servlet 被称为
<img src="pathToServlet/PathToDICOMFile">.
问题:当我有很多标签(当然是针对不同的 DICOM 文件)时,有时我会遇到 java.util.ConcurrentModificationException 类型的异常
这是方法,我的servlet正在调用:
void convertFile(String path, OutputStream to) throws IOException {
File myDicomFile = new File(path);
BufferedImage myJpegImage = null;
ImageIO.scanForPlugins();
Iterator<ImageReader> iter = ImageIO.getImageReadersByFormatName("DICOM");
ImageReader reader = (ImageReader) iter.next();
DicomImageReadParam param = (DicomImageReadParam) reader.getDefaultReadParam();
ImageInputStream iis = ImageIO.createImageInputStream(myDicomFile);
reader.setInput(iis, false);
myJpegImage = reader.read(0, param);
iis.close();
ImageIO.write(myJpegImage, "JPEG", to);
to.close();
}
"path" 是 dicom 文件的绝对路径,"out" 只是 response.getOutputStream()。
可以在 3 个地方抛出异常:
- ImageIO.getImageReadersByFormatName("DICOM");
- myJpegImage = reader.read(0, param);
- ImageIO.write(myJpegImage, "JPEG", to);
这是调用 ImageIO.getImageReadersByFormatName("DICOM") 时抛出的堆栈跟踪:
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:806)
at java.util.HashMap$ValueIterator.next(HashMap.java:835)
at javax.imageio.spi.PartialOrderIterator.<init>(PartiallyOrderedSet.java:177)
at javax.imageio.spi.PartiallyOrderedSet.iterator(PartiallyOrderedSet.java:85)
at javax.imageio.spi.SubRegistry.getServiceProviders(ServiceRegistry.java:759)
at javax.imageio.spi.ServiceRegistry.getServiceProviders(ServiceRegistry.java:451)
at javax.imageio.spi.ServiceRegistry.getServiceProviders(ServiceRegistry.java:507)
at javax.imageio.ImageIO.getImageReadersByFormatName(ImageIO.java:708)
at example.project.dicomtest.myDicomConverter.ConvertHelper.convertFile(ConvertHelper.java:32)
at example.project.dicomtest.myDicomConverter.GetImage.doGet(GetImage.java:40)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:185)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:151)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEnginateValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:269)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
是因为 ImageIO 不是线程安全的吗?我能做些什么来解决这个问题?非常感谢您的帮助和问候!