Question

我正在编写一些代码，使用GAE的转换API对PDF进行验证。目前，我在运行＆＃34; ConversionResult result = service.convert（conv）;＆＃34;时收到空指针错误。我已经尝试复制教程中包含的代码（https://developers.google.com/appengine/docs/java/conversion/overview），但我不得不搞砸从BlobStore获取Asset对象。我已粘贴下面的代码和堆栈跟踪;什么想法可能是错的？我试过尝试捕捉，但这只会导致方法安静地失败。此外，我无法使用内置的错误代码方法，因为没有创建ConversionResult对象。我一直在寻找解决这个问题的方法，虽然我发现了一些类似问题的帖子，但我还没有找到任何解决方案。此外，每个人似乎都在使用我上面链接的相同示例代码;谷歌真的没有关于转换的更多文档吗？

感谢您的帮助！

public static void parse(String key, BlobKey bkey) throws IOException {

        BlobstoreInputStream in = new BlobstoreInputStream(bkey);
        byte[] attachmentData = IOUtils.toByteArray(in);
        in.read(attachmentData);

        System.out.println(attachmentData.toString());
        System.out.println(attachmentData.length);
        System.out.println("parse(): blob fetched");

        //Prep for conversion
        Asset fileAsset = new Asset("application/pdf", attachmentData);
        System.out.println(fileAsset.getData().toString());
        Document pdfDoc = new Document(fileAsset);

        ConversionOptions options = ConversionOptions.Builder
                .withOcrInputLanguage("en");
        Conversion conv = new Conversion(pdfDoc, "text/plain", options);
        if (conv.equals(null))
            System.out.println("Conversion is null!");

        // Actual conversion (takes a while!)
        ConversionService service = ConversionServiceFactory.getConversionService();
        if (service.equals(null))
            System.out.println("Service is null!");
        // Fails below!!
        // ¯\(°_o)/¯
        ConversionResult result = service.convert(conv);
        ConversionErrorCode err = result.getErrorCode();
        System.out.println(err.toString());

        // Check for success, return conversion as String
        System.out.println("parse(): 7");
        if (result.success()) {
            System.out.println("parse(): 8");
            // Usually, there will only be 1 asset, but running it through a for loop to be sure
            System.out.println("parse(): 9");
            for (Asset asset : result.getOutputDoc().getAssets()) {
                System.out.println("parse(): 10");
                String text = new String(asset.getData());
                System.out.println("parse(): 11");
                System.out.println(text);

            }
        }
        else { //PDF not converted
            System.out.println("Error: PDF not converted");
            // Maybe add more error handling

        }
}

警告

2012年8月20日下午3:10:55 com.google.apphosting.utils.jetty.JettyLogger警告

警告：/verifyPDF.jsp 显示java.lang.NullPointerException 在com.google.appengine.api.conversion.ConversionServicePb $ AssetInfo $ Builder.setName（ConversionServicePb.java:886）在com.google.appengine.api.conversion.AssetProtoConverter.doForward（AssetProtoConverter.java:30）在com.google.appengine.api.conversion.AssetProtoConverter.doForward（AssetProtoConverter.java:17）在com.google.appengine.repackaged.com.google.common.base.Converter.convert（Converter.java:52）在com.google.appengine.api.conversion.DocumentProtoConverter.doForward（DocumentProtoConverter.java:33）在com.google.appengine.api.conversion.DocumentProtoConverter.doForward（DocumentProtoConverter.java:18）在com.google.appengine.repackaged.com.google.common.base.Converter.convert（Converter.java:52）在com.google.appengine.api.conversion.ConversionProtoConverter.doForward（ConversionProtoConverter.java:38）在com.google.appengine.api.conversion.ConversionProtoConverter.doForward（ConversionProtoConverter.java:16）在com.google.appengine.repackaged.com.google.common.base.Converter.convert（Converter.java:52）在com.google.appengine.api.conversion.ConversionRequestProtoConverter.doForward（ConversionRequestProtoConverter.java:40）在com.google.appengine.api.conversion.ConversionRequestProtoConverter.doForward（ConversionRequestProtoConverter.java:19）在com.google.appengine.repackaged.com.google.common.base.Converter.convert（Converter.java:52）在com.google.appengine.api.conversion.ConversionServiceImpl.convertAsync（ConversionServiceImpl.java:94）在com.google.appengine.api.conversion.ConversionServiceImpl.convert（ConversionServiceImpl.java:66）在com.google.appengine.api.conversion.ConversionServiceImpl.convert（ConversionServiceImpl.java:59）在coupflipsite.PDFVerify.parse（PDFVerify.java:73）在org.apache.jsp.verifyPDF_jsp._jspService（verifyPDF_jsp.java:65）在org.apache.jasper.runtime.HttpJspBase.service（HttpJspBase.java:97）在javax.servlet.http.HttpServlet.service（HttpServlet.java:717）在org.apache.jasper.servlet.JspServletWrapper.service（JspServletWrapper.java:377）在org.apache.jasper.servlet.JspServlet.serviceJspFile（JspServlet.java:313）在org.apache.jasper.servlet.JspServlet.service（JspServlet.java:260）在com.google.appengine.tools.development.PrivilegedJspServlet.access $ 101（PrivilegedJspServlet.java:23）在com.google.appengine.tools.development.PrivilegedJspServlet $ 2.run（PrivilegedJspServlet.java:59） at java.security.AccessController.doPrivileged（Native Method）在com.google.appengine.tools.development.PrivilegedJspServlet.service（PrivilegedJspServlet.java:57）在javax.servlet.http.HttpServlet.service（HttpServlet.java:717）在org.mortbay.jetty.servlet.ServletHolder.handle（ServletHolder.java:511）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1166）在com.google.appengine.tools.development.HeaderVerificationFilter.doFilter（HeaderVerificationFilter.java:35）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1157）在com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter（ServeBlobFilter.java:60）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1157）在com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter（TransactionCleanupFilter.java:43）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1157）在com.google.appengine.tools.development.StaticFileFilter.doFilter（StaticFileFilter.java:125）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1157）在com.google.appengine.tools.development.BackendServersFilter.doFilter（BackendServersFilter.java:97）在org.mortbay.jetty.servlet.ServletHandler $ CachedChain.doFilter（ServletHandler.java:1157）在org.mortbay.jetty.servlet.ServletHandler.handle（ServletHandler.java:388）在org.mortbay.jetty.security.SecurityHandler.handle（SecurityHandler.java:216）在org.mortbay.jetty.servlet.SessionHandler.handle（SessionHandler.java:182）在org.mortbay.jetty.handler.ContextHandler.handle（ContextHandler.java:765）在org.mortbay.jetty.webapp.WebAppContext.handle（WebAppContext.java:418）在com.google.appengine.tools.development.DevAppEngineWebAppContext.handle（DevAppEngineWebAppContext.java:94）在org.mortbay.jetty.handler.HandlerWrapper.handle（HandlerWrapper.java:152）在com.google.appengine.tools.development.JettyContainerService $ ApiProxyHandler.handle（JettyContainerService.java:370）在org.mortbay.jetty.handler.HandlerWrapper.handle（HandlerWrapper.java:152）在org.mortbay.jetty.Server.handle（Server.java:326）在org.mortbay.jetty.HttpConnection.handleRequest（HttpConnection.java:542）在org.mortbay.jetty.HttpConnection $ RequestHandler.content（HttpConnection.java:938）在org.mortbay.jetty.HttpParser.parseNext（HttpParser.java:755）在org.mortbay.jetty.HttpParser.parseAvailable（HttpParser.java:218）在org.mortbay.jetty.HttpConnection.handle（HttpConnection.java:404）在org.mortbay.io.nio.SelectChannelEndPoint.run（SelectChannelEndPoint.java:409）在org.mortbay.thread.QueuedThreadPool $ PoolThread.run（QueuedThreadPool.java:582）

Answer 1

首先：转化API为being decommissioned in Nov 2012。你应该切换到别的东西。

关于您的问题 - 尝试将“name”参数添加到Asset构造函数：

Asset fileAsset = new Asset("application/pdf", attachmentData, "filename.pdf");

将PDF转换为纯文本时转换API NPE

1 个答案: