XSLT 3.0 流(撒克逊) [英] XSLT 3.0 streaming (Saxon)

问题描述

我有一个带有这种树的大 XML 文件 (6 GB):

I have a big XML file (6 GB) with this kind of tree:

<Report>
   <Document>
      <documentType>E</documentType>
      <person>
         <firstname>John</firstname>
         <lastname>Smith</lastname>
      </person>
   </Document>
   <Document>
      [...]
   </Document>
   <Document>
      [...]
   </Document>
   [...]
</Report>

如果我在其上应用 XSLT 样式表，则会出现此错误:

If I apply an XSLT style sheet on it, I have this error:

线程main"中的异常 java.lang.OutOfMemoryError: Java heap space

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space

所以我想尝试新的 XSLT 3.0 特性:流媒体，使用 Saxon 9.6 EE.我不想在 Document 中设置一次流约束.我认为，我想要做的非常接近此处描述的突发模式":http://saxonica.com/documentation/html/sourcedocs/streaming/burst-mode-streaming.html

So I wanted to try the new XSLT 3.0 feature: streaming, with Saxon 9.6 EE. I don't want to have the streaming constrains once in a Document. I think that, what I want to do, is very close to the "burst mode" that is described here: http://saxonica.com/documentation/html/sourcedocs/streaming/burst-mode-streaming.html

这是我的 Saxon 命令行:

Here is my Saxon command line:

java -cp saxon9ee.jar net.sf.saxon.Transform -t -s:input.xml -xsl:stylesheet.xsl -o:output/output.html

java -cp saxon9ee.jar net.sf.saxon.Transform -t -s:input.xml -xsl:stylesheet.xsl -o:output/output.html

这是我的 XSLT 样式表:

Here is my XSLT style sheet:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="3.0">
<xsl:mode streamable="yes" />

<xsl:template match="/">
    GLOBAL HEADER
        <xsl:iterate select="copy-of()/Report/Document" >
           DOC HEADER
           documentType: <xsl:value-of select="documentType"/>
           person/firstname: <xsl:value-of select="person/firstname"/>
           DOC FOOTER
           <xsl:next-iteration/>
        </xsl:iterate>
    GLOBAL FOOTER
</xsl:template>

</xsl:stylesheet>

但我仍然有同样的内存不足错误.

But I still have the same out of memory error.

感谢您的帮助！

推荐答案

您的 copy-of() 正在复制上下文项，即整个文档.你想要

Your copy-of() is copying the context item, which is the entire document. You want

copy-of(/Report/Document)

依次复制每个文档.或者我倾向于写它

which copies each Document in turn. Or I tend to write it

/Report/Document/copy-of()

因为我认为它可以更清楚地说明正在发生的事情.

because I think it makes it clearer what is going on.

顺便说一下，这里不需要 xsl:iterate:xsl:for-each 可以很好地完成这项工作，因为对一个 Document 的处理不依赖于对任何先前文档的处理.

Incidentally you don't need xsl:iterate here: xsl:for-each will do the job perfectly well, because processing of one Document doesn't depend on the processing of any previous documents.

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