dom4j中使用xpath解析带命名空间的xml文件,取不到节点的解决办法

<?xml version="1.0" encoding="gbk" standalone="yes"?>
<unit xmlns="http://www.sdml.info/srcML/src" xmlns:cpp="http://www.sdml.info/srcML/cpp">
<cpp:ifndef>
<name>test</name>
</cpp:ifndef>
<class>class</class>
</unit>

public static void main(String [] args){
Document document = XmlTools.getDoc(file.getPath());
HashMap xmlMap = new HashMap();
xmlMap.put("src", "http://www.sdml.info/srcML/src");
xmlMap.put("cpp", "http://www.sdml.info/srcML/cpp");
// 以下可以访问到
XPath x0 = document.createXPath("unit/src:class");
XPath x1 = document.createXPath("src:unit/src:class");
XPath x2 = document.createXPath("/unit/src:class");
XPath x3 = document.createXPath("unit/src:class");
XPath x4 = document.createXPath("/unit/cpp:define");
XPath x6 = document.createXPath("unit/cpp:define");
XPath x7 = document.createXPath("src:unit/cpp:define");
// 以下访问不到
XPath x8 = document.createXPath("unit/class");
XPath x9 = document.createXPath("unit/define");
XPath x10 = document.createXPath("/unit/class");
XPath x11 = document.createXPath("/unit/define");
XPath x12 = document.createXPath("src:unit/class");
XPath x13 = document.createXPath("src:unit/define");
XPath x14 = document.createXPath("unit/cpp:class");
XPath x15 = document.createXPath("unit/src:define");
test(x0, document, xmlMap);
test(x1, document, xmlMap);
test(x2, document, xmlMap);
test(x3, document, xmlMap);
test(x4, document, xmlMap);
test(x6, document, xmlMap);
test(x7, document, xmlMap);
test(x8, document, xmlMap);
test(x9, document, xmlMap);
test(x10, document, xmlMap);
test(x11, document, xmlMap);
test(x12, document, xmlMap);
test(x13, document, xmlMap);
test(x14, document, xmlMap);
test(x15, document, xmlMap);
}
static void test(XPath x, Document doc, Map map) {
x.setNamespaceURIs(map);
System.out.println("运行结果:"+x.selectNodes(doc).size());
}

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