Java 6 中对 xinclude 的默认支持？

Question

我在我的应用程序中看到我解析的 XML 文件中的 xinclude 在我的 Java XSLT 转换中不起作用。

但是，虽然我这样做了：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setXIncludeAware(true);

我没有专门将变压器工厂设置为 System.getProperty("javax.xml.transform.TransformerFactory") 返回“null”。

我的问题：默认 Java（1.6 或 6）是否支持 xinclude，或者我是否必须添加替代 XSLT 解析器，例如 Apache Xerces？

Answer 1

根据the spec，从 Java 1.5 (5) 开始就提供支持。我相信 XInclude 支持依赖于namespace awareness，出于向后兼容性的原因，默认情况下它是关闭的。

public class XIncludeDemo {

    private static final String XML = "<?xml version=\"1.0\"?>\n"
            + "<data xmlns=\"foo\" xmlns:xi=\"http://www.w3.org/2001/XInclude\">\n"
            + "<xi:include href=\"include.txt\" parse=\"text\"/>\n"
            + "</data>\n";

    private static final String INCLUDE = "Hello, World!";

    public static void main(String[] args) throws Exception {
        // data
        final InputStream xmlStream = new ByteArrayInputStream(XML
                .getBytes("UTF-8"));
        final InputStream includeStream = new ByteArrayInputStream(INCLUDE
                .getBytes("UTF-8"));
        // document parser
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setXIncludeAware(true);
        factory.setNamespaceAware(true);
        DocumentBuilder docBuilder = factory.newDocumentBuilder();
        if (!docBuilder.isXIncludeAware()) {
            throw new IllegalStateException();
        }
        docBuilder.setEntityResolver(new EntityResolver() {
            @Override
            public InputSource resolveEntity(String publicId, String systemId)
                    throws SAXException, IOException {
                if (systemId.endsWith("include.txt")) {
                    return new InputSource(includeStream);
                }
                return null;
            }
        });
        Document doc = docBuilder.parse(xmlStream);
        // print result
        Source source = new DOMSource(doc);
        Result result = new StreamResult(System.out);
        TransformerFactory transformerFactory = TransformerFactory
                .newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        transformer.transform(source, result);
    }

}