在Java中使用SAXON Xpath引擎 [英] Using SAXON Xpath engine in Java

问题描述

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();
    }

}

我明白了：

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Java正在使用 org.apache.xpath.compiler。当我通过 net.sf.saxon.xpath.XPathFactoryImpl 清楚地创建我的工厂时，XPathParser 类。

Which means Java is using org.apache.xpath.compiler.XPathParser class when I clearly created my factory through net.sf.saxon.xpath.XPathFactoryImpl.

（实际上我只需要在我的xpath中放一些匹配 ...所以如果任何不涉及Saxon的解决方案已知，请考虑我的需要。）

(I actually only need to put some matches in my xpaths... so if any solution not involving Saxon is known, consider my need reached).

我做错了什么？

推荐答案

来自撒克逊的例子：

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

工作正常。

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