使用 XPATH java 提取 XML 嵌套内容

Question

im trying to extract xml nested contents for my dependencies tag in my pom. But it is not getting the correct dependenices tag eventhough the location is specified. any help? This is my pom.xml

<project
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
        xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

    
    
    <build>
            <plugin>
                <artifactId>maven-antrun-plugin</artifactId>
                <version>1.8</version>
                <dependencies>
                    <dependency>
                        <groupId>org.apache.ant</groupId>
                        <artifactId>ant-nodeps</artifactId>
                        <version>1.8.1</version>
                    </dependency>

                </dependencies>
    </build>

    <dependencies>
        <dependency>
            <groupId>com.intent.tm</groupId>
            <artifactId>commons-io</artifactId>
            <version>1.0.0.1</version>
        </dependency>
        <!-- For Compress JS -->
        <dependency>
            <groupId>com.yahoo.platform.yui</groupId>
            <artifactId>yuicompressor</artifactId>
            <version>2.4.7</version>
        </dependency>
        <dependency>
            <groupId>com.sybase</groupId>
            <artifactId>EccpressoFIPSJca</artifactId>
            <version>7.0</version>
        </dependency>

this is my code

private static String nodeToString(Node node) throws TransformerException {
        StringWriter buf = new StringWriter();
        Transformer xform = TransformerFactory.newInstance().newTransformer();
        xform.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        xform.transform(new DOMSource(node), new StreamResult(buf));
        return (buf.toString());
    

}

File fXmlFile = new File(prop.getProperty("testFile"));
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        Document document;
        Node result = null;
       
            document = dbf.newDocumentBuilder().parse(fXmlFile);
            XPath xPath = XPathFactory.newInstance().newXPath();
            String xpathStr = "//project//dependencies";
            result = (Node) xPath.evaluate(xpathStr, document, XPathConstants.NODE);
            log.info(nodeToString(result));

Actual output:

<dependencies>
                    <dependency>
                        <groupId>org.apache.ant</groupId>
                        <artifactId>ant-nodeps</artifactId>
                        <version>1.8.1</version>
                    </dependency>

                </dependencies>

Expected output:

<dependencies>
        <dependency>
            <groupId>com.intent.tm</groupId>
            <artifactId>commons-io</artifactId>
            <version>1.0.0.1</version>
        </dependency>
        <!-- For Compress JS -->
        <dependency>
            <groupId>com.yahoo.platform.yui</groupId>
            <artifactId>yuicompressor</artifactId>
            <version>2.4.7</version>
        </dependency>
        <dependency>
            <groupId>com.sybase</groupId>
            <artifactId>EccpressoFIPSJca</artifactId>
            <version>7.0</version>
        </dependency>

For some reason it is printing the dependencies in the build tag when the location specified is not build..im confused why this is happening and is there anyway to get my expected out?

Answer 1

In XPath // can match any number of subpaths, so it finds dependencies inside the build section too. If I change your code to say

 String xpathStr = "/project/dependencies";

I get the output you wanted. One slash is to match exactly one level in the XML, so we get project from the root, then dependencies straight under project.