Develop Reference

XPath concat same tagname

I'm trying with this attempt to produce an xml based on the one given, joining values of same TagName.
For example this is what I've done so far:
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
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 org.w3c.dom.Document;
import org.xml.sax.SAXException;
public class TestXPath {
public static void main(String[] args) throws SAXException, IOException, ParserConfigurationException, XPathExpressionException {
String xml =
"<ROOT>" +
" <coolnessId>9</coolnessId>" +
" <cars id=\"3\">0</cars>" +
" <cars id=\"2\">1</cars>" +
" <cars id=\"1\">2</cars>" +
"</ROOT>";
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
Document doc = factory.newDocumentBuilder().parse(new ByteArrayInputStream(xml.getBytes(StandardCharsets.UTF_8)));
XPath xpath = XPathFactory.newInstance().newXPath();
///XPathExpression expr = xpath.compile("concat(//ROOT/cars,'-',//ROOT/coolnessId)");//concat(//ROOT/cars)
XPathExpression expr = xpath.compile("concat(//ROOT/cars,'-')");//concat(//ROOT/cars)
// XPathExpression expr = xpath.compile( "concat(//*[contains(name(), 'cars')],'')");
System.out.println(expr.evaluate(doc, XPathConstants.STRING));
}
}
This code produces:
0-
Now this is what should be:
2-1-0
As you can see the values follow the attribute "id" of each "cars" tag.
I've rearrenged many times but can't achieve my result.
Please keep in mind I'm on a very old enviroment such as Java 1.4 runtime.

I think it's going to be simplest to retrieve the nodes using XPath, and then concatenate the string values in Java code.
Any other solution involves upgrading your technology: XSLT, XPath 2.0+, etc, and that isn't going to be easy on a JDK 1.4 platform.

Creating simple document with JDOM

I am trying to create a simple Document with Jdom.
I strictly followed the instructions given on
https://www.tutorialspoint.com/java_xml/java_dom_create_document.htm
I cannot understand why, no matter what I do, I end up with a [document:null].
This is my code :
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;
import java.util.*;
import org.jdom2.*;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
public class Network {
public Document SetToXml() throws Exception {
Document doc = null;
try {
DocumentBuilderFactory DBF =
DocumentBuilderFactory.newInstance();
DocumentBuilder DB = DBF.newDocumentBuilder();
doc = DB.newDocument();
Element root = doc.createElement("network");
root.setAttribute("name", Name);
doc.appendChild(root);
}
}
}
When I inspect the doc variable, it always contains [document:null].
Is there any way out or should I give up ?
Thanks

I would say, no need to worry :)
The "[document:null]" string which your debugger is showing you is only the toString() - representation of the document object. I do not yet understand, why it actually looks like this, but I verified that regardless of this, the document actually has the "netwrok" element you specified and also the name attribute you are assigning to it.

How to get data safely from DOM object when multiple threads are accessing same object

I have multiple threads trying to read the same DOM object and runs simultaneously.
But I heard that, DOM is not thread safe and somewhere I read that if we clone the document, that cloned document will be thread safe.
this is what I wanted to try
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
public class Demo {
public static void main(String[] args) throws Exception {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document originalDocument = db.parse(new File("input.xml"));
Node originalRoot = originalDocument.getDocumentElement();
Document copiedDocument = db.newDocument();
Node copiedRoot = copiedDocument.importNode(originalRoot, true);
copiedDocument.appendChild(copiedRoot);
}
}
Now I will allow my threads to read from copiedDocument, instead of originalDocument.
So, Now Do my code runs in thread safe or not? Could anyone please confirm.

xml file is successfully parsed from netbeans but not from runnable jar

i developed a code that parses an xml file and returns result in a frame in netbeans .The code runs successfully from netbeans but when exporting the project into jar file it shows nothing .Please ,if you have ideas ,i will be thankful if you help me .Here is the code i used for parsing .
import java.io.IOException;
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.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;
public class Parsing {
String a = null;
public static void main(String a) throws
ParserConfigurationException, SAXException, IOException,
XPathExpressionException {
a = getElem(a);
}
public static String getElem(String a) throws ParserConfigurationException, SAXException, XPathExpressionException, IOException {
String file = "src/xml/read.xml";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(false);
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(file);
XPath xpath = XPathFactory.newInstance().newXPath();
Node CustomerId = (Node) xpath.evaluate("//Operation[#name='Read' and #modifier='Customer']/ParameterList/StringParameter[#name='CustomerId']/text()",
doc.getDocumentElement(), XPathConstants.NODE);
a = CustomerId.getNodeValue();
return a;
}
}
when calling the method getElem(a) from another frame it shows me the value of a in a textbox ,but when exporting the project into a jar file it doesn't show me anything !

First thing that strikes me is the use of relative path to your XML resource. It seems you rely on existence of a file in a directory relative to your working dir.

The src directory will not exist at run time. This suggests that the XML file is an em ebbed resource, and as such, can't get accessed as a file would be if it lived on the file system.
Instead you want to use something like...
getClass().getResourceAsStream("/xml/read.xml")
And pass the resulting InputStream to DocumentBuilder. Don't forget to close it

here is the modified code that worked with jar file :)
import java.io.IOException;
import java.io.InputStream;
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.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class Parsing {
String a = null;
private static final String TEST_XML = "/xml/read.xml";
public static void main(String a) throws
ParserConfigurationException, SAXException, IOException,
XPathExpressionException {
a = getElem(a);
}
protected static InputSource getTestXMLInputSource() {
InputStream is = Parsing.class.getResourceAsStream(TEST_XML);
is = Parsing.class.getResourceAsStream(TEST_XML);
return new InputSource(is);
}
public static String getElem(String a) throws ParserConfigurationException, SAXException, XPathExpressionException, IOException {
final InputSource source = getTestXMLInputSource();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(false);
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(source);
XPath xpath = XPathFactory.newInstance().newXPath();
Node CustomerId = (Node) xpath.evaluate("//Operation[#name='Read' and #modifier='Customer']/ParameterList/StringParameter[#name='CustomerId']/text()",
doc.getDocumentElement(), XPathConstants.NODE);
a = CustomerId.getNodeValue();
return a;
}
}

Overwriting an existing XML document in Java using dom parsers api

I would like to know how do I overwrite and existing element in Java using dom parser. for example, I have the file
I am trying to overwrite the element and replace it with the element
Thanks.

Algorithm is easy:
Read a file and parse it to XML document
Make any changes you want
Overwrite existing file with new content
See my example:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
public class DomProgram {
public static void main(String[] args) throws Exception {
File xmlFile = new File("C:\\test.xml");
Document document = readXmlDocument(xmlFile);
makeChanges(document);
Transformer transformer = createXmlTransformer();
overwriteXmlFile(xmlFile, document, transformer);
}
private static void overwriteXmlFile(File xmlFile, Document document,
Transformer transformer) throws FileNotFoundException,
TransformerException {
StreamResult result = new StreamResult(new PrintWriter(
new FileOutputStream(xmlFile, false)));
DOMSource source = new DOMSource(document);
transformer.transform(source, result);
}
private static Transformer createXmlTransformer() throws Exception {
Transformer transformer = TransformerFactory.newInstance()
.newTransformer();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
return transformer;
}
private static void makeChanges(Document document) {
Element root = document.getDocumentElement();
root.setAttribute("test", "testvalue");
}
private static Document readXmlDocument(File xmlFile) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(xmlFile);
return document;
}
}
Example XML file:
<note>
<to>Ebele</to>
<from>mykhaylo</from>
<heading>Reminder</heading>
<body>Read about problem before you ask ;)</body>
</note>
Also see:
Simple Java DOM XML Example
How To Read XML File In Java – (DOM Parser)