如何在Java中获取子节点值

Question

我正在努力获取子节点值：

我的XML文件：

<url-mappings>
    <url-mapping url="/screen1">
        <request-handler-class>com.mappingtool.rh.Screen1RH</request-handler-class>
    </url-mapping>
    <url-mapping url="/screen2">
        <request-handler-class>com.mappingtool.rh.Screen2RH</request-handler-class>
    </url-mapping>
</url-mappings>

我的代码是：

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import java.io.File;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class MappingTool {

    public static void main(String[] args) throws Exception {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document document = db.parse(new File("src/com/mappingtool/requestmapping.xml"));
        NodeList nodeList = document.getElementsByTagName("url-mapping");
        XPath xpath = XPathFactory.newInstance().newXPath();
        for(int x=0,size= nodeList.getLength(); x<size; x++) {
            System.out.println(nodeList.item(x).getAttributes().getNamedItem("url").getNodeValue());
            //System.out.println(nodeList.item(x).getChildNodes().item(0));
            //XPathExpression expr = xpath.compile("/request-handler-class/text()");
            XPathExpression expr = xpath.compile("/url-mappings/url-mapping/request-handler-class/text()");
            //XPathExpression expr = xpath.compile("/url-mappings/url-mapping["+ x +"]/request-handler-class/text()");
            String rhClass = (String)expr.evaluate(nodeList.item(x), XPathConstants.STRING);
            System.out.println(rhClass);
        }
    }
}

我正在获得输出

/screen1
com.mappingtool.rh.Screen1RH
/screen2
com.mappingtool.rh.Screen1RH

但我需要

/screen1
com.mappingtool.rh.Screen1RH
/screen2
com.mappingtool.rh.Screen2RH

Answer 1

您可以使用类似XPathExpression expr = xpath.compile("/url-mappings/url-mapping[contains(@url,'"+nodeValue+"')]/request-handler-class/text()");的表达式，其中nodeValue是由第一个System.out.println打印的值。