多线程下获取PDF中的图片信息报错：Not supported image type

pizhai2 · August 1, 2025, 2:16pm

代码如下，正常使用则没有问题，但是添加了线程池就会报错：
com.aspose.pdf.internal.ms.System.l7n: Not supported image type
at com.aspose.pdf.XImage.lI(Unknown Source)
at com.aspose.pdf.XImage.saveInternal(Unknown Source)
at com.aspose.pdf.XImage.saveInternal(Unknown Source)
at com.aspose.pdf.XImage.getImage(Unknown Source)
代码如下：

    /**
     * 获取PDF文档中的所有图片
     *
     * @param pdfFilePath PDF文件路径
     * @return 图片列表
     */
    public static List<BufferedImage> getImages(String pdfFilePath) {

        List<BufferedImage> images = new ArrayList<>();
        try (Document document = new Document(pdfFilePath)) {
            PageCollection pages = document.getPages();

            int pageSize = pages.size();

            if (pageSize > 5) {

                ExecutorService executorService = Executors.newFixedThreadPool(7);
                List<Future<List<BufferedImage>>> futures = new ArrayList<>();

                for (int i = 1; i <= pageSize; i += 5) {
                    int endPage = Math.min(i + 4, pageSize);
                    int finalI = i;
                    Future<List<BufferedImage>> future = executorService.submit(() -> getImages(pdfFilePath, finalI, endPage));
                    futures.add(future);
                }

                for (Future<List<BufferedImage>> future : futures) {
                    try {
                        images.addAll(future.get());
                    } catch (Exception e) {
                        throw new RuntimeException("获取图片失败", e);
                    }
                }

                executorService.shutdown();
            } else {

                pages.forEach(page -> images.addAll(getImages(page)));
            }

            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * 获取指定页面的所有图片
     *
     * @param pdfFilePath     PDF文件路径
     * @param startPageNumber 起始页面索引，从1开始
     * @param endPageNumber   结束页面索引，从1开始
     * @return 图片列表
     */
    public static List<BufferedImage> getImages(String pdfFilePath,
                                                int startPageNumber,
                                                int endPageNumber) {

        try (Document document = new Document(pdfFilePath)) {
            PageCollection pages = document.getPages();
            List<BufferedImage> images = new ArrayList<>();
            for (int i = startPageNumber; i <= endPageNumber; i++) {
                if (i > pages.size()) {
                    break;
                }
                Page page = pages.get_Item(i);
                images.addAll(getImages(page));
            }
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    public static List<BufferedImage> getImages(Page page) {

        List<BufferedImage> images = new ArrayList<>();
        try {
            ImagePlacementAbsorber absorber = new ImagePlacementAbsorber();
            page.accept(absorber);
            for (ImagePlacement imagePlacement : absorber.getImagePlacements()) {
                images.add(imagePlacement.getImage().getImage().lf());
            }
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

Professionalize.Discourse · August 1, 2025, 2:17pm

@pizhai2

在多线程环境中处理PDF文件时，出现“Not supported image type”错误通常是由于线程之间的资源竞争或不当的资源管理导致的。以下是一些可能的原因和解决步骤：

原因与解决方案

资源共享：确保每个线程都在独立的上下文中处理PDF文档，避免多个线程同时访问同一个Document实例。
线程安全：考虑使用ThreadLocal来为每个线程提供独立的Document实例，以防止资源竞争。
异常处理：在捕获异常时，确保记录详细的错误信息，以便更好地调试。
图像处理：在获取图像时，确保图像类型是支持的格式。可以在处理图像之前添加类型检查。

下一步

请参考以下修改后的代码示例，使用ThreadLocal来确保每个线程都有自己的Document实例：

public static List<BufferedImage> getImages(String pdfFilePath) {
    List<BufferedImage> images = new ArrayList<>();
    ThreadLocal<Document> threadLocalDocument = ThreadLocal.withInitial(() -> new Document(pdfFilePath));

    try {
        PageCollection pages = threadLocalDocument.get().getPages();
        int pageSize = pages.size();

        if (pageSize > 5) {
            ExecutorService executorService = Executors.newFixedThreadPool(7);
            List<Future<List<BufferedImage>>> futures = new ArrayList<>();

            for (int i = 1; i <= pageSize; i += 5) {
                int endPage = Math.min(i + 4, pageSize);
                int finalI = i;
                Future<List<BufferedImage>> future = executorService.submit(() -> getImages(threadLocalDocument.get(), finalI, endPage));
                futures.add(future);
            }

            for (Future<List<BufferedImage>> future : futures) {
                try {
                    images.addAll(future.get());
                } catch (Exception e) {
                    throw new RuntimeException("获取图片失败", e);
                }
            }

            executorService.shutdown();
        } else {
            pages.forEach(page -> images.addAll(getImages(page)));
        }

        return images;
    } catch (Exception e) {
        throw new RuntimeException(e);
    } finally {
        threadLocalDocument.remove(); // 清理ThreadLocal
    }
}

public static List<BufferedImage> getImages(Document document, int startPageNumber, int endPageNumber) {
    // 处理指定页面的图像
}

通过这种方式，每个线程都将拥有自己的Document实例，从而避免了资源竞争问题。请按照上述建议进行调整，并测试代码以确保问题得到解决。如果还有其他问题，请随时告诉我！

pizhai2 · August 1, 2025, 2:21pm

你提供的代码无效，依然报同样的错误，请转人工。

asad.ali · August 1, 2025, 8:45pm

@pizhai2

如果可能，请提供以下信息：

完整的堆栈跟踪
示例 PDF 文档

另外，请确认您是否尝试使用 25.6 版本的 PDF。我们将根据情况进一步处理。

pizhai2 · August 1, 2025, 9:11pm

我使用的是25.6版本。
文件如下：
homeworkId_27477_type_16.0.pdf (8.7 MB)

pizhai2 · August 1, 2025, 10:15pm

com.aspose.pdf.internal.ms.System.l7n: Not supported image type
	at com.aspose.pdf.XImage.lI(Unknown Source)
	at com.aspose.pdf.XImage.saveInternal(Unknown Source)
	at com.aspose.pdf.XImage.saveInternal(Unknown Source)
	at com.aspose.pdf.XImage.getImage(Unknown Source)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.getImages(AsposePdfUtils.java:256)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.getImages(AsposePdfUtils.java:168)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImages$0(AsposePdfUtils.java:225)
	at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:840)

pizhai2 · August 1, 2025, 10:53pm

发现即使是@Async方法调用，也会有问题：

com.aspose.pdf.internal.ms.System.l7n: Not supported image type
        at com.aspose.pdf.XImage.lI(Unknown Source)
        at com.aspose.pdf.XImage.saveInternal(Unknown Source)
        at com.aspose.pdf.XImage.saveInternal(Unknown Source)
        at com.aspose.pdf.XImage.getImage(Unknown Source)
        at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.getImages(AsposePdfUtils.java:220)
        at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImages$0(AsposePdfUtils.java:206)
        at java.base/java.lang.Iterable.forEach(Iterable.java:75)
        at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.getImages(AsposePdfUtils.java:206)
        at cn.df2680.aihomework.dddpo.dotmatrix.DotUnitASDownloaderImpl.getPdfImagesWithRetry(DotUnitASDownloaderImpl.java:721)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:568)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:351)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:196)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
        at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:113)
        at org.springframework.util.concurrent.FutureUtils.lambda$toSupplier$0(FutureUtils.java:74)
        at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
        at java.base/java.lang.Thread.run(Thread.java:842)

代码：

// 接口
    @Async("ioTaskExecutor")
    CompletableFuture<List<BufferedImage>> getPdfImages(String pdfPath);
//实现
    public CompletableFuture<List<BufferedImage>> getPdfImages(String pdfPath) {
        List<BufferedImage> images = AsposePdfUtils.getImages(pdfPath);
        return CompletableFuture.completedFuture(images);
    }
//工具类实现
    public static List<BufferedImage> getImages(String pdfFilePath) {

        List<BufferedImage> images = new ArrayList<>();
        try (Document document = new Document(pdfFilePath)) {
            PageCollection pages = document.getPages();
            pages.forEach(page -> images.addAll(getImages(page)));
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static List<BufferedImage> getImages(Page page) {

        List<BufferedImage> images = new ArrayList<>();
        try {
            ImagePlacementAbsorber absorber = new ImagePlacementAbsorber();
            page.accept(absorber);
            for (ImagePlacement imagePlacement : absorber.getImagePlacements()) {
                images.add(imagePlacement.getImage().getImage().lf());
            }
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

所以aspose.pdf不支持多线程使用？

pizhai2 · August 2, 2025, 4:37am

我可以得到回复了吗？？？？

pizhai2 · August 2, 2025, 3:14pm

The code is as follows; this is an asynchronous method annotated with the @Async annotation.

// interface
    @Async("ioTaskExecutor")
    CompletableFuture<List<BufferedImage>> getPdfImages(String pdfPath);
//impl
    public CompletableFuture<List<BufferedImage>> getPdfImages(String pdfPath) {
        List<BufferedImage> images = AsposePdfUtils.getImages(pdfPath);
        return CompletableFuture.completedFuture(images);
    }
//utils
    public static List<BufferedImage> getImages(String pdfFilePath) {

        List<BufferedImage> images = new ArrayList<>();
        try (Document document = new Document(pdfFilePath)) {
            PageCollection pages = document.getPages();
            pages.forEach(page -> images.addAll(getImages(page)));
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static List<BufferedImage> getImages(Page page) {

        List<BufferedImage> images = new ArrayList<>();
        try {
            ImagePlacementAbsorber absorber = new ImagePlacementAbsorber();
            page.accept(absorber);
            for (ImagePlacement imagePlacement : absorber.getImagePlacements()) {
                images.add(imagePlacement.getImage().getImage().lf());
            }
            return images;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

Error message as follows：

class com.aspose.pdf.internal.ms.System.l7n: Not supported image type
com.aspose.pdf.XImage.lI(Unknown Source)
com.aspose.pdf.XImage.saveInternal(Unknown Source)
com.aspose.pdf.XImage.saveInternal(Unknown Source)
com.aspose.pdf.XImage.getImage(Unknown Source)
cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImagesInParallel$0(AsposePdfUtils.java:263)
java.base/java.lang.Iterable.forEach(Iterable.java:75)
cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImagesInParallel$1(AsposePdfUtils.java:258)
java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run$$$capture(CompletableFuture.java:1768)
java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
java.base/java.lang.Thread.run(Thread.java:840)
	at com.aspose.pdf.XImage.lI(Unknown Source)
	at com.aspose.pdf.XImage.saveInternal(Unknown Source)
	at com.aspose.pdf.XImage.saveInternal(Unknown Source)
	at com.aspose.pdf.XImage.getImage(Unknown Source)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImagesInParallel$0(AsposePdfUtils.java:263)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.lambda$getImagesInParallel$1(AsposePdfUtils.java:258)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run$$$capture(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java)
	at --- Async.Stack.Trace --- (captured by IntelliJ IDEA debugger)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.<init>(CompletableFuture.java:1754)
	at java.base/java.util.concurrent.CompletableFuture.asyncSupplyStage(CompletableFuture.java:1782)
	at java.base/java.util.concurrent.CompletableFuture.supplyAsync(CompletableFuture.java:2005)
	at cn.df2680.aihomework.utils.pub.pdf.AsposePdfUtils.getImagesInParallel(AsposePdfUtils.java:253)
	at cn.df2680.aihomework.controller.TestController.getImages(TestController.java:538)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:351)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:196)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:765)
	at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:58)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:173)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:765)
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:89)
	at cn.df2680.aihomework.aop.CountTimeAop.around(CountTimeAop.java:30)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:637)
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:627)
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:71)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:173)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:765)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:765)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:717)
	at cn.df2680.aihomework.controller.TestController$$SpringCGLIB$$0.getImages(<generated>)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:569)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:261)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:189)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:917)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:829)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:205)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at cn.dev33.satoken.filter.SaFirewallCheckFilterForJakartaServlet.doFilter(SaFirewallCheckFilterForJakartaServlet.java:69)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at cn.dev33.satoken.filter.SaTokenCorsFilterForJakartaServlet.doFilter(SaTokenCorsFilterForJakartaServlet.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at cn.dev33.satoken.filter.SaTokenContextFilterForJakartaServlet.doFilter(SaTokenContextFilterForJakartaServlet.java:40)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.springframework.web.filter.ServerHttpObservationFilter.doFilterInternal(ServerHttpObservationFilter.java:109)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:340)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:840)

PDF file as follows：
homeworkId_27477_type_16.0.pdf (8.7 MB)

version information as follows：25.6

Professionalize.Discourse · August 2, 2025, 3:15pm

@pizhai2

The error message “Not supported image type” typically indicates that the Aspose library is encountering an image format in the PDF that it cannot process. This can happen for several reasons, especially when working with multithreading.

Cause:

The issue arises when the PDF contains images in unsupported formats or when multithreading is not managed properly, leading to conflicts.

Solution:

Check Image Formats: Ensure that the images in your PDF are in supported formats. Aspose.PDF supports common formats like JPEG, PNG, and BMP. If the PDF contains images in unsupported formats, you will need to handle those cases separately.
Thread Safety: Since you are using multithreading, ensure that each thread is working with its own instance of the Document class. Sharing a single instance across threads can lead to unpredictable behavior and errors.
Error Handling: Enhance your error handling to log the specific image type that is causing the issue. This can help you identify unsupported formats.
Use PdfExtractor: Consider using the PdfExtractor class, which is specifically designed for extracting images and text from PDFs. It may provide better handling for various image types.

Next Steps:

Here’s a modified version of your image extraction logic using PdfExtractor:

public static List<BufferedImage> getImages(String pdfFilePath) {
    List<BufferedImage> images = new ArrayList<>();
    try (PdfExtractor extractor = new PdfExtractor()) {
        extractor.bindPdf(pdfFilePath);
        extractor.extractImage();
        while (extractor.hasNextImage()) {
            BufferedImage image = extractor.getNextImage();
            if (image != null) {
                images.add(image);
            }
        }
    } catch (Exception e) {
        throw new RuntimeException("Error extracting images: " + e.getMessage(), e);
    }
    return images;
}

This approach ensures that you are using a dedicated extractor for image extraction, which may help avoid the unsupported image type error.

Please implement these suggestions and let me know if you need further assistance!

pizhai2 · August 2, 2025, 3:21pm

The method ‘getNextImage()’ in BufferedImage image = extractor.getNextImage() cannot be resolved; it requires parameters.

is working with its own instance of the Document class.

the PDF not contains images in unsupported formats.

pizhai2 · August 2, 2025, 3:26pm

PdfExtractor doesn’t work and can’t retrieve any images at all!

asad.ali · August 2, 2025, 8:58pm

@pizhai2

我们需要对这个问题进行详细调查。为此，我们将会在我们的问题追踪系统中创建一个工单，并会很快将工单编号与您分享。

asad.ali · August 2, 2025, 9:13pm

@pizhai2

我们已在内部问题跟踪系统中创建了以下新工单，并将根据Free Support Policies中提到的条款交付其修复。

问题编号：PDFJAVA-45239

如果您需要优先支持服务，可以通过Paid Support Services获取，同时直接联系我们的付费支持管理团队。