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)
Related
Im trying to insert a comment with syntax version information before the first node of an xml document but for some reason it always gets appended after the last element. I cant use other libraries like XStream and such.
I have already tried to do this via the append and the insertBefore method but both of them yield the same result. Is it possible to do this just with the plain Document, Comment and Node or do I have to use a Transformer?
Document doc = XmlDocumentUtil.createDocument();
//Create root node
Node rootNode = doc.createElement(NODE_DATA_CONFIGURATION);
doc.appendChild(rootNode);
//Create syntax identification comment
Comment syntaxIdentification = doc.createComment(writeSyntaxIdentificationQE);
doc.insertBefore(syntaxIdentification, rootNode);
//Create revision information
Element modificationNumber = doc.createElement("modificationNumber");
modificationNumber.setTextContent(String.valueOf(configTable.getModificationNumber()));
rootNode.appendChild(modificationNumber);
Element modificationTime = doc.createElement("modificationTime");
modificationTime.setTextContent(configTable.getModificationTime());
rootNode.appendChild(modificationTime);
Element modifier = doc.createElement("modifier");
modifier.setTextContent(configTable.getModifier());
rootNode.appendChild(modifier);
for (...) {
... some data generation
}
What I get:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<DataConfiguration>
<modificationNumber>2</modificationNumber>
<modificationTime>2019-07-25 07:42:28.804 +0200</modificationTime>
<modifier>testuser</modifier>
<someData idxFrom="4" idxTo="9"
signalName="1" signalOffset="273.15" signalTemplate="asdf" skip="Y"/>
</DataConfiguration>
<!--SyntaxIdentification: 1.0-->
What I need:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!--SyntaxIdentification: 1.0-->
<DataConfiguration>
<modificationNumber>2</modificationNumber>
<modificationTime>2019-07-25 07:42:28.804 +0200</modificationTime>
<modifier>testuser</modifier>
<someData idxFrom="4" idxTo="9"
signalName="1" signalOffset="273.15" signalTemplate="asdf" skip="Y"/>
</DataConfiguration>
To me your code seems good overall. Seems like you are missing only text nodes.
Here is full working code.
package xml;
import java.io.StringWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
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.*;
public class XMLComment {
public static void main(String[] args) throws ParserConfigurationException, TransformerException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.newDocument();
// Create root node
Node rootNode = doc.createElement("DataConfiguration");
doc.appendChild(rootNode);
// Create syntax identification comment
Comment syntaxIdentification = doc.createComment("SyntaxIdentification: 1.0");
doc.insertBefore(syntaxIdentification, rootNode);
// Create modificationNumber
Node modificationNumber = doc.createElement("modificationNumber");
Text mnText = doc.createTextNode("123456");
modificationNumber.appendChild(mnText);
// Create modificationTime
Element modificationTime = doc.createElement("modificationTime");
Text mtText = doc.createTextNode("2019-07-25 07:42:28.804 +0200");
modificationTime.appendChild(mtText);
rootNode.appendChild(modificationNumber);
rootNode.appendChild(modificationTime);
printXML(doc);
}
private static void printXML(Document doc) throws TransformerException {
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
// initialize StreamResult with File object to save to file
StreamResult result = new StreamResult(new StringWriter());
DOMSource source = new DOMSource(doc);
transformer.transform(source, result);
String xmlString = result.getWriter().toString();
System.out.println(xmlString);
}
}
It will output, close to what exactly you are looking for.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!--SyntaxIdentification: 1.0--><DataConfiguration>
<modificationNumber>123456</modificationNumber>
<modificationTime>2019-07-25 07:42:28.804 +0200</modificationTime>
</DataConfiguration>
Hope it helps.
This question already has answers here:
Modify the content of a file using Java
(6 answers)
Closed 5 years ago.
I have the below code that writes to an xml file, the problem that I am having is that it creates a new file every time i write to it and overwrites the other data saved in the file. I am looking for a solution that would append to the existing file instead. How do I modify this code to append to the file each time instead of overwrite? Also, I am using the netbeans IDE to run this program.
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
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;
import org.xml.sax.SAXException;
public class WriteXMLFile {
public static void main() throws ParserConfigurationException,SAXException,Exception
{
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();//
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();//
Document doc = docBuilder.newDocument();// this is difrent
Element rootElement = doc.createElement("Contacts");//
doc.appendChild(rootElement); // this is difrent
// staff elements
Element Contact1 = doc.createElement("Contact1");
rootElement.appendChild(Contact1);
// set attribute to staff element
Contact1.setAttribute("id","1");
// firstname elements
Element firstname = doc.createElement("Name");
firstname.appendChild(doc.createTextNode(EmailFrame.name.getText()));
Contact1.appendChild(firstname);
//Email Element
Element email = doc.createElement("Email");
email.appendChild(doc.createTextNode(EmailFrame.email.getText()));
Contact1.appendChild(email);
// phone element
Element phone= doc.createElement("Phone");
phone.appendChild(doc.createTextNode(EmailFrame.phone.getText()));
Contact1.appendChild(phone);
//id element
Element id = doc.createElement("ID");
id.appendChild(doc.createTextNode(EmailFrame.id.getText()));
Contact1.appendChild(id);
try{
// write the content into xml file
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File("C:/Users/steve/Desktop/xmlemail/Email.xml"));
transformer.transform(source, result);
System.out.println("File saved!");
}
catch (TransformerException tfe) {
tfe.printStackTrace();
}
}
}
What you need to do is read the contents of the xml file into an object first before writing, then append your new content to your object then write your object to the xml file
Look at this resource for reading an xml file it should help
https://www.mkyong.com/java/how-to-read-xml-file-in-java-dom-parser/
I used JAXB to create a very complicated .xml file which I saved on the drive. I also manually made an .xsl file which is my template.
How do I now programmatically use the above two to create an html output file ?
I tried various things and maybe I'm just tired but I can't even successfully open the .xml file into a Document.
Does someone have a working example ? I would greatly appreciate it! Thanks :)
I tried various things, including the official code examples but I can't find a working example. Nothing but null pointer exceptions. :(
The smallest working example I can give you:
import java.io.File;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
public class UseXMLToHTML {
public static void main(String[] args) throws TransformerException {
StreamResult result = new StreamResult(new File("output.html"));
StreamSource source = new StreamSource(new File("input.xml"));
StreamSource xslt = new StreamSource(new File("transform.xslt"));
Transformer transformer = TransformerFactory.newInstance().newTransformer(xslt);
transformer.transform(source, result);
}
}
This would probably do the trick;
import javax.xml.transform.*;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
public class TestMain {
public static void main(String[] args) throws IOException, URISyntaxException, TransformerException {
TransformerFactory factory = TransformerFactory.newInstance();
Source xslt = new StreamSource(new File("transform.xslt"));
Transformer transformer = factory.newTransformer(xslt);
Source text = new StreamSource(new File("input.xml"));
transformer.transform(text, new StreamResult(new File("output.xml")));
}
}
Consider trying out stuff from these urls:
http://www.w3schools.com/xsl/tryxslt.asp?xmlfile=cdcatalog&xsltfile=cdcatalog
http://www.w3schools.com/xsl/tryxslt_result.asp?xmlfile=cdcatalog&xsltfile=cdcatalog
I'm in a part of an application where I have an access to the XmlStreamReader which is representing the XML file needed to be fully read into a String.
Is there a way to obtain the XML content without building another XmlStreamReader or using another stream on the file?
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.stax.StAXSource;
import javax.xml.transform.stream.StreamResult;
private String getOuterXml(XMLStreamReader xmlr) throws TransformerConfigurationException,
TransformerFactoryConfigurationError, TransformerException
{
Transformer transformer = TransformerFactory.newInstance().newTransformer();
StringWriter stringWriter = new StringWriter();
transformer.transform(new StAXSource(xmlr), new StreamResult(stringWriter));
return stringWriter.toString();
}
import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class modifyXML {
public static void modify(StringBuffer XMLBuffer) throws IOException, ParserConfigurationException, SAXException{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new ByteArrayInputStream(XMLBuffer.toString().getBytes()));
Element rootNode = doc.getDocumentElement();
NodeList priceList = rootNode.getElementsByTagName("price");
priceList.item(0).setTextContent("190");
NodeList inStockList = rootNode.getElementsByTagName("id_product_attribute");
inStockList.item(0).setTextContent("100");
}
}
I am trying to modify an XML file and then put it all back together. I have managed with the modifying part, but I can not get the XML file back together. The result can be either a String or a StringBuffer.
What is the best/easiest way to do this?
Use a Transformer as described by WhiteFang34 in XML Document to String.
Official Java Tutorials: Writing Out a DOM as an XML File (just make StreamResult Wrap something else such as StringWriter).
Update:
Less known, shorter alternative by ykaganovich based on Load / Save objects: