XPath: compile(String expression) throws XPathExpressionException : XPath « javax.xml.xpath « Java by API

1. Java by API
2. javax.xml.xpath
3. XPath

XPath: compile(String expression) throws XPathExpressionException

  


import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Hashtable;

import javax.xml.namespace.QName;
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 javax.xml.xpath.XPathVariableResolver;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class Main {
  public static void main(String[] args) throws Exception {
    SimpleDateFormat xmlDateFormat = new SimpleDateFormat("MM.dd.yy");

    MapVariableResolver resolver = new MapVariableResolver();
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = dbf.newDocumentBuilder();
    Document document = builder.parse(new File("t.xml"));

    XPathFactory factory = XPathFactory.newInstance();
    XPath xPath = factory.newXPath();
    xPath.setXPathVariableResolver(resolver);
    XPathExpression expression = xPath.compile("/schedule/show[@date=$date]/guest");

    String formattedDate = xmlDateFormat.format(new Date(2006, 5, 14));
    resolver.addVariable(null, "date", formattedDate);
    Element guest = (Element) expression.evaluate(document, XPathConstants.NODE);

    System.out.println(guest.getElementsByTagName("name").item(0).getTextContent());
  }
}

class MapVariableResolver implements XPathVariableResolver {

  private Hashtable variables = new Hashtable();

  public void addVariable(String namespaceURI, String localName, Object value) {
    addVariable(new QName(namespaceURI, localName), value);
  }

  public void addVariable(QName name, Object value) {
    variables.put(name, value);
  }

  public Object resolveVariable(QName name) {
    Object retval = variables.get(name);
    return retval;
  }
}

   
    
  

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