将XML字符串转换为CSV文件（Java）-> CSV结果为空

Question

I need help understanding why the XML String does not convert into a CSV file. Why is the CSV Resut always empty?

Here is an example of a Java Code

public class transformCSV_1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        try {
            String xmlData = new String(
                    "<?xml version=\"1.0\"?><PurchaseOrder  xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:noNamespaceSchemaLocation=\"http://localhost:8080/source/schemas/poSource/xsd/purchaseOrder.xsd\"><Reference>SBELL-2002100912333601PDT</Reference><Actions><Action><User>SVOLLMAN</User></Action></Actions><Requestor>Sarah J. Bell</Requestor><User>SBELL</User><CostCenter>S30</CostCenter><ShippingInstructions><name>Sarah J. Bell</name><address>400 Oracle Parkway Redwood Shores CA 94065 USA</address><telephone>650 506 7400</telephone></ShippingInstructions><SpecialInstructions>Air Mail</SpecialInstructions><LineItems><LineItem ItemNumber=\"1\"><Description>A Night to Remember</Description><Part Id=\"715515009058\" UnitPrice=\"39.95\" Quantity=\"2\"/></LineItem><LineItem ItemNumber=\"2\"><Description>The Unbearable Lightness Of Being</Description><Part Id=\"37429140222\" UnitPrice=\"29.95\" Quantity=\"2\"/></LineItem><LineItem ItemNumber=\"3\"><Description>Sisters</Description><Part Id=\"715515011020\" UnitPrice=\"29.95\" Quantity=\"4\"/></LineItem></LineItems></PurchaseOrder>");
            String stylesheet = new String(
                    "<?xml version=\"1.0\" encoding=\"utf-8\"?><xsl:stylesheet version=\"1.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\"><xsl:output method=\"text\" /><xsl:variable name=\"delimiter\" select=\"','\" /><!-- define an array containing the fields we are interested in --><xsl:variable name=\"fieldArray\"><field>Reference</field><field>User</field><field>Reject</field><field>Requestor</field></xsl:variable><xsl:param name=\"fields\" select=\"document('')/*/xsl:variable[@name='fieldArray']/*\" /><xsl:template match=\"/\"><!-- output the header row --><xsl:for-each select=\"$fields\"><xsl:if test=\"position() != 1\"><xsl:value-of select=\"$delimiter\"/></xsl:if><xsl:value-of select=\".\" /></xsl:for-each><!-- output newline --><xsl:text>&#xa;</xsl:text><xsl:apply-templates select=\"PurchaseOrder\"/></xsl:template><xsl:template match=\"PurchaseOrder\"><xsl:variable name=\"currNode\" select=\".\" /><!-- output the data row --><!-- loop over the field names and find the value of each one in the xml --><xsl:for-each select=\"$fields\"><xsl:if test=\"position() != 1\"><xsl:value-of select=\"$delimiter\"/></xsl:if><xsl:value-of select=\"$currNode/*[name() = current()]\" /></xsl:for-each><!-- output newline --><xsl:text>&#xa;</xsl:text></xsl:template></xsl:stylesheet>");

            InputStream xmlSource = new ByteArrayInputStream(
                    xmlData.getBytes("UTF-8"));
            InputStream styleSource = new ByteArrayInputStream(
                    stylesheet.getBytes("UTF-8"));

            DocumentBuilderFactory factory = DocumentBuilderFactory
                    .newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document document = builder.parse(xmlSource);

            StreamSource stylesource = new StreamSource(styleSource);
            Transformer transformer = TransformerFactory.newInstance()
                    .newTransformer(stylesource);
            Source source = new DOMSource(document);
            Result outputTarget = new StreamResult(new File("src/resultI.csv"));
            transformer.transform(source, outputTarget);

        } catch (TransformerConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (TransformerFactoryConfigurationError e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (TransformerException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

Best way is to use XSLT to "transform" the XML to CSV --> Can someone give me hint?

Answer 1

考虑从文件或URI（而不是字符串）中加载XSLT代码，否则您的方法<xsl:param name="fields" select="document('')/*/xsl:variable[@name='fieldArray']/*" /> ，除非您设置了特殊的解析程序，否则document('')尝试再次拉入XSLT代码的操作很可能会失败。