如何从XML以字符串格式获取重复的标签值（Java）

Question

I Have an xml in this format:

<Container1>
<Description>one</Description>
</Container1>
<Container2>
<Description>Two</Description>
</Container2>

Am reading this xml to a String.(There is a reason why I cant parse the xml directly) Now from that String I need to take the values of all Description tags to a List Any clues on how to do this?

Answer 1

Since you are receiving the xml ,you can parse it and the use XPath to extract the necessary information. Please note that you need to pass the valid xml to builder#parse (I wrapped your xml in root element).

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

public class XPathExtractor {

    public static void main(String[] args) throws XPathExpressionException, IOException, SAXException, ParserConfigurationException {
        String s = "<root>\n" +
                "<Container1>\n" +
                "<Description>one</Description>\n" +
                "</Container1>\n" +
                "<Container2>\n" +
                "<Description>Two</Description>\n" +
                "</Container2>\n" +
                "</root>";
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document doc = builder.parse(new ByteArrayInputStream(s.getBytes(StandardCharsets.UTF_8)));
        XPath xpath = XPathFactory.newInstance().newXPath();
        XPathExpression descriptionExpr = xpath.compile("//Description/text()");
        Object result = descriptionExpr.evaluate(doc, XPathConstants.NODESET);
        NodeList nodes = (NodeList) result;
        for (int i = 0; i < nodes.getLength(); i++) {
            System.out.println(nodes.item(i).getNodeValue());
        }
    }
}

Outputs

one
Two