在Java中使用SAXON Xpath引擎

Question

这是我的代码：

public static void main(String[] args) {

    // System.setProperty(
    // "javax.xml.xpath.XPathFactory", 
    // "net.sf.saxon.xpath.XPathFactoryImpl");

    String xml="<root><a>#BBB#</a><a>#CCC#</a><b><a>#DDD#</a></b></root>";
    try{
        JDocument dom = new JDocument(xml);

        XPathFactory factory = net.sf.saxon.xpath.XPathFactoryImpl.newInstance();
        XPath xpath = factory.newXPath();
        XPathExpression expr = xpath.compile("//a[matches(.,'#...#')]");

        Object result = expr.evaluate(dom, XPathConstants.NODESET);
        NodeList nodes = (NodeList) result;
        Nodes sharped = new Nodes(nodes);

        for (Node n:sharped){
            System.out.println(n.toString());
        }
    }
    catch(Exception e){
        e.printStackTrace();
    }

}

我得到这个：

javax.xml.transform.TransformerException: Impossible to find the function : matches
at org.apache.xpath.compiler.XPathParser.error(XPathParser.java:608)
at org.apache.xpath.compiler.XPathParser.FunctionCall(XPathParser.java:1505)
at org.apache.xpath.compiler.XPathParser.PrimaryExpr(XPathParser.java:1444)
at org.apache.xpath.compiler.XPathParser.FilterExpr(XPathParser.java:1343)
at org.apache.xpath.compiler.XPathParser.PathExpr(XPathParser.java:1276)

这意味着org.apache.xpath.compiler.XPathParser当我通过明确创建工厂时，Java正在使用类net.sf.saxon.xpath.XPathFactoryImpl。

（实际上，我只需要matches在xpaths中放置一些…因此，如果知道不涉及Saxon的任何解决方案，请考虑达到了我的需要）。

我究竟做错了什么 ？

Answer 1

从撒克逊人的例子：

System.setProperty("javax.xml.xpath.XPathFactory:"+NamespaceConstant.OBJECT_MODEL_SAXON, "net.sf.saxon.xpath.XPathFactoryImpl");
XPathFactory xpf = XPathFactory.newInstance(NamespaceConstant.OBJECT_MODEL_SAXON);

工作良好。