Develop Reference

How to modify values of multiple XML tags?

I have been trying to modify values of more than one XML tag in java. So far I am able to get the values of the two nodes that I want to modify but while setting up values it always overrides the first one with the second one.
XML
<driver>
<BirthDate>1977-07-18</BirthDate>
<Age>40</Age>
<Gender>M</Gender>
<PrimaryResidence>OwnCondo</PrimaryResidence>
</driver>
I am trying to change Gender and PrimaryResidence tags.
Code
// Modifies multiple XML nodes
public static String changeCoreDiscountType(String reqXML) {
Document document = null;
String updatedXML = null;
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
InputSource is = new InputSource();
is.setCharacterStream(new StringReader(reqXML));
document = builder.parse(is);
XPath xPath = XPathFactory.newInstance().newXPath();
XPathExpression expression = xPath.compile("/driver/Gender | /driver/PrimaryResidence");
NodeList nodeList = (NodeList) expression.evaluate(document,XPathConstants.NODESET);
for(int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
node.setTextContent("F");
node.setTextContent("OwnCondo");
String value = node.getTextContent();
}
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(document);
StreamResult result = new StreamResult(new StringWriter());
transformer.transform(source, result);
updatedXML = result.getWriter().toString();
} catch (Exception ex) {
ex.printStackTrace();
}
return updatedXML;
}
Any help is appreciated.

You need to check you are updating the correct node first, e.g.
for(int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
if(node.getNodeName() == "Gender")
node.setTextContent("F");
if(node.getNodeName() == "PrimaryResidence")
node.setTextContent("OwnCondo");
}
Full Demo

How to update multiple nodes in xml in Java

I am trying to update multiple nodes in xml using nodelist. I am able to do it but i don't think my code is efficient. For updating two nodes I am repeating my code twice. I dont know how to loop it. I tried it from for loop, or tried making it an arraylist and everything but it is not working at all.
Here is my code:
String expressionDisclosure = "/DOCUMENT/ishobject/ishfields/ishfield[#name='FHPIDISCLOSURELEVEL']";
String expressionLanguage = "/DOCUMENT/ishobject/ishfields/ishfield[#name='DOC-LANGUAGE']";
String key = "";
String value = "";
try {
DocumentBuilderFactory documentbuilderfactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentbuilder = documentbuilderfactory.newDocumentBuilder();
Document doc = documentbuilder.parse(filepath);
XPath xPath = XPathFactory.newInstance().newXPath();
Node updateNode = null;
NodeList nodelistLanguage = (NodeList) xPath.evaluate(expressionLanguage,
doc.getDocumentElement(), XPathConstants.NODESET);
NodeList nodelistDisclosure = (NodeList) xPath.evaluate(expressionDisclosure,
doc.getDocumentElement(), XPathConstants.NODESET);
key = nodelistLanguage.item(0).getTextContent();
if (key != null) {
value = getHashmap().get(key);
updateNode = nodelistLanguage.item(0);
updateNode.setTextContent(value);
}
key = nodelistDisclosure.item(0).getTextContent();
if (key != null) {
value = getHashmap().get(key);
updateNode = nodelistDisclosure.item(0);
updateNode.setTextContent(value);
}
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult stream = new StreamResult(new File(filepath));
transformer.transform(source, stream);
} catch (Exception ex) {
ex.printStackTrace();
}
I am updating the node twice. Is this the proper way to do or can it be more efficient?

Pretty print XML in java 8

I have an XML file stored as a DOM Document and I would like to pretty print it to the console, preferably without using an external library. I am aware that this question has been asked multiple times on this site, however none of the previous answers have worked for me. I am using java 8, so perhaps this is where my code differs from previous questions? I have also tried to set the transformer manually using code found from the web, however this just caused a not found error.
Here is my code which currently just outputs each xml element on a new line to the left of the console.
import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class Test {
public Test(){
try {
//java.lang.System.setProperty("javax.xml.transform.TransformerFactory", "org.apache.xalan.xsltc.trax.TransformerFactoryImpl");
DocumentBuilderFactory dbFactory;
DocumentBuilder dBuilder;
Document original = null;
try {
dbFactory = DocumentBuilderFactory.newInstance();
dBuilder = dbFactory.newDocumentBuilder();
original = dBuilder.parse(new InputSource(new InputStreamReader(new FileInputStream("xml Store - Copy.xml"))));
} catch (SAXException | IOException | ParserConfigurationException e) {
e.printStackTrace();
}
StringWriter stringWriter = new StringWriter();
StreamResult xmlOutput = new StreamResult(stringWriter);
TransformerFactory tf = TransformerFactory.newInstance();
//tf.setAttribute("indent-number", 2);
Transformer transformer = tf.newTransformer();
transformer.setOutputProperty(OutputKeys.METHOD, "xml");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.transform(new DOMSource(original), xmlOutput);
java.lang.System.out.println(xmlOutput.getWriter().toString());
} catch (Exception ex) {
throw new RuntimeException("Error converting to String", ex);
}
}
public static void main(String[] args){
new Test();
}
}

In reply to Espinosa's comment, here is a solution when "the original xml is not already (partially) indented or contain new lines".
Background
Excerpt from the article (see References below) inspiring this solution:
Based on the DOM specification, whitespaces outside the tags are perfectly valid and they are properly preserved. To remove them, we can use XPath’s normalize-space to locate all the whitespace nodes and remove them first.
Java Code
public static String toPrettyString(String xml, int indent) {
try {
// Turn xml string into a document
Document document = DocumentBuilderFactory.newInstance()
.newDocumentBuilder()
.parse(new InputSource(new ByteArrayInputStream(xml.getBytes("utf-8"))));
// Remove whitespaces outside tags
document.normalize();
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList nodeList = (NodeList) xPath.evaluate("//text()[normalize-space()='']",
document,
XPathConstants.NODESET);
for (int i = 0; i < nodeList.getLength(); ++i) {
Node node = nodeList.item(i);
node.getParentNode().removeChild(node);
}
// Setup pretty print options
TransformerFactory transformerFactory = TransformerFactory.newInstance();
transformerFactory.setAttribute("indent-number", indent);
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
// Return pretty print xml string
StringWriter stringWriter = new StringWriter();
transformer.transform(new DOMSource(document), new StreamResult(stringWriter));
return stringWriter.toString();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
Sample usage
String xml = "<root>" + //
"\n " + //
"\n<name>Coco Puff</name>" + //
"\n <total>10</total> </root>";
System.out.println(toPrettyString(xml, 4));
Output
<root>
<name>Coco Puff</name>
<total>10</total>
</root>
References
Java: Properly Indenting XML String published on MyShittyCode
Save new XML node to file

I guess that the problem is related to blank text nodes (i.e. text nodes with only whitespaces) in the original file. You should try to programmatically remove them just after the parsing, using the following code. If you don't remove them, the Transformer is going to preserve them.
original.getDocumentElement().normalize();
XPathExpression xpath = XPathFactory.newInstance().newXPath().compile("//text()[normalize-space(.) = '']");
NodeList blankTextNodes = (NodeList) xpath.evaluate(original, XPathConstants.NODESET);
for (int i = 0; i < blankTextNodes.getLength(); i++) {
blankTextNodes.item(i).getParentNode().removeChild(blankTextNodes.item(i));
}

This works on Java 8:
public static void main (String[] args) throws Exception {
String xmlString = "<hello><from>ME</from></hello>";
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(new InputSource(new StringReader(xmlString)));
pretty(document, System.out, 2);
}
private static void pretty(Document document, OutputStream outputStream, int indent) throws Exception {
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
if (indent > 0) {
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", Integer.toString(indent));
}
Result result = new StreamResult(outputStream);
Source source = new DOMSource(document);
transformer.transform(source, result);
}

I've written a simple class for for removing whitespace in documents - supports command-line and does not use DOM / XPath.
Edit: Come to think of it, the project also contains a pretty-printer which handles existing whitespace:
PrettyPrinter prettyPrinter = PrettyPrinterBuilder.newPrettyPrinter().ignoreWhitespace().build();

Underscore-java has static method U.formatXml(string). I am the maintainer of the project. Live example
import com.github.underscore.U;
public class MyClass {
public static void main(String args[]) {
String xml = "<root>" + //
"\n " + //
"\n<name>Coco Puff</name>" + //
"\n <total>10</total> </root>";
System.out.println(U.formatXml(xml));
}
}
Output:
<root>
<name>Coco Puff</name>
<total>10</total>
</root>

I didn't like any of the common XML formatting solutions because they all remove more than 1 consecutive new line character (for some reason, removing spaces/tabs and removing new line characters are inseparable...). Here's my solution, which was actually made for XHTML but should do the job with XML as well:
public String GenerateTabs(int tabLevel) {
char[] tabs = new char[tabLevel * 2];
Arrays.fill(tabs, ' ');
//Or:
//char[] tabs = new char[tabLevel];
//Arrays.fill(tabs, '\t');
return new String(tabs);
}
public String FormatXHTMLCode(String code) {
// Split on new lines.
String[] splitLines = code.split("\\n", 0);
int tabLevel = 0;
// Go through each line.
for (int lineNum = 0; lineNum < splitLines.length; ++lineNum) {
String currentLine = splitLines[lineNum];
if (currentLine.trim().isEmpty()) {
splitLines[lineNum] = "";
} else if (currentLine.matches(".*<[^/!][^<>]+?(?<!/)>?")) {
splitLines[lineNum] = GenerateTabs(tabLevel) + splitLines[lineNum];
++tabLevel;
} else if (currentLine.matches(".*</[^<>]+?>")) {
--tabLevel;
if (tabLevel < 0) {
tabLevel = 0;
}
splitLines[lineNum] = GenerateTabs(tabLevel) + splitLines[lineNum];
} else if (currentLine.matches("[^<>]*?/>")) {
splitLines[lineNum] = GenerateTabs(tabLevel) + splitLines[lineNum];
--tabLevel;
if (tabLevel < 0) {
tabLevel = 0;
}
} else {
splitLines[lineNum] = GenerateTabs(tabLevel) + splitLines[lineNum];
}
}
return String.join("\n", splitLines);
}
It makes one assumption: that there are no <> characters except for those that comprise the XML/XHTML tags.

Create xml file :
new FileInputStream("xml Store - Copy.xml") ;// result xml file format incorrect !
so that, when parse the content of the given input source as an XML document
and return a new DOM object.
Document original = null;
...
original.parse("data.xml");//input source as an XML document

updated xml data not updated in the xml file

i have made a method for updating my xml in the xml file by a using a GUI..
but when I update it everything seem to be working fine and the console is printing out the correct things.
But when I open the xml file and press refrah nothing is updated.
What is my problem?
public void updateObjType(String newTxt, int x) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {
System.out.println("String value : " + newTxt);
System.out.println("Index value : " + x);
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document xmlDocument = builder.parse("xmlFiles/CoreDatamodel.xml");
XPath xPath = XPathFactory.newInstance().newXPath();
// Go thru the Object_types in the XML file and get item x.
NodeList nodeList = (NodeList) xPath.compile("//OBJECT_TYPE/text()")
.evaluate(xmlDocument, XPathConstants.NODESET);
// Set new NodeValue
nodeList.item(x).setNodeValue(newTxt);
String value = nodeList.item(x).getTextContent();
System.out.println(value);
}
this is the output from the console :
Original data : IF150Data
Incoming String value : Data
Index value : 4
updated data : Data

I solved it by using a transformer.
Full solution :
// Update the object type name from the object type list.
public void updateObjType(String newTxt, int x)
throws ParserConfigurationException, SAXException, IOException,
XPathExpressionException {
File file = new File("xmlFiles/CoreDatamodel.xml");
System.out.println("Incoming String value : " + newTxt);
System.out.println("Index value : " + x);
DocumentBuilderFactory builderFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document xmlDocument = builder.parse(file);
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList nodeList = (NodeList) xPath.compile("//OBJECT_TYPE/text()")
.evaluate(xmlDocument, XPathConstants.NODESET);
// Set new NodeValue
nodeList.item(x).setNodeValue(newTxt);
// Save the new updates
try {
save(file, xmlDocument);
} catch (Exception e) {
e.printStackTrace();
}
}
And then the method I added :
public void save(File file, Document doc) throws Exception {
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
StringWriter writer = new StringWriter();
StreamResult result = new StreamResult(writer);
DOMSource source = new DOMSource(doc);
transformer.transform(source, result);
String s = writer.toString();
System.out.println(s);
FileWriter fileWriter = new FileWriter(file);
BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
bufferedWriter.write(s);
bufferedWriter.flush();
bufferedWriter.close();
}

Append to XML file

I am writing a Java application with a method to save data to XML.
Here is my code:
private void SaveToXML(String strCity, String strDate, String strforecast, String strminDegrees, String FileName)
{
try
{
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("Weather");
doc.appendChild(rootElement);
Element weatherElement = doc.createElement(strCity);
rootElement.appendChild(weatherElement);
Element dateElement = doc.createElement("Date");
weatherElement.appendChild(dateElement);
Attr attr = doc.createAttribute("id");
attr.setValue(strDate);
dateElement.setAttributeNode(attr);
Element forecast = doc.createElement("forecast");
forecast.appendChild(doc.createTextNode(strforecast));
dateElement.appendChild(forecast);
Element mindegrees = doc.createElement("mindegrees");
mindegrees.appendChild(doc.createTextNode(strminDegrees));
dateElement.appendChild(mindegrees);
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(FileName));
transformer.transform(source, result);
} catch (ParserConfigurationException pce) {
pce.printStackTrace();
} catch (TransformerException tfe) {
tfe.printStackTrace();
}
}
Method call:
SaveToXML("Auckland", "24-05-2013", "Fine", "10", "Test.xml");
Here is the output XML data:
<?xml version="1.0" encoding="UTF-8"?>
<Weather>
<Auckland>
<Date id="24-05-2013">
<forecast>Fine</forecast>
<mindegrees>10</mindegrees>
</Date>
</Auckland>
</Weather>
Can I please have some help to modify the code so that data is appended to the document in the correct element when the method is called.
E.g, If the method is called a second time with the City of Auckland, the weather details will be placed in the Auckland element. If a City is passed as a parameter that is not already in the document, a new element for that City will be created.
UPDATE2
This is my current code that performs an error:
private void SaveToXML(String strCity, String strDate, String strforecast, String strminDegrees, String FileName)
{
try
{
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
//Document doc = docBuilder.newDocument();
Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(new File(FileName));
Element rootElement = doc.createElement("Weather");
doc.appendChild(rootElement);
NodeList weatherNodes = rootElement.getElementsByTagName(strCity);// do we already have node?
Element weatherElement;
if(weatherNodes.getLength() > 0){ // if so reuse
weatherElement = (Element) weatherNodes.item(0);
System.out.println("Found");
}else { // else create
weatherElement = doc.createElement(strCity);
rootElement.appendChild(weatherElement);
}
Element dateElement = doc.createElement("Date");
weatherElement.appendChild(dateElement);
Attr attr = doc.createAttribute("id");
attr.setValue(strDate);
dateElement.setAttributeNode(attr);
Element forecast = doc.createElement("forecast");
forecast.appendChild(doc.createTextNode(strforecast));
dateElement.appendChild(forecast);
Element mindegrees = doc.createElement("mindegrees");
mindegrees.appendChild(doc.createTextNode(strminDegrees));
dateElement.appendChild(mindegrees);
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(FileName));
transformer.transform(source, result);
} catch (Exception ex) {
ex.printStackTrace();
}
}
The above code generates this error at runtime:
[Fatal Error] Test.xml:1:177: The markup in the document following the root element must be well-formed.
org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed.
UPDATE3
Here is the code that is working:
private void SaveToXML(String strCity, String strDate, String strforecast, String strminDegrees, String FileName)
{
try
{
DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc;
File file = new File(FileName);
if (!file.exists()) {
doc = docBuilder.newDocument();
doc.appendChild(doc.createElement("Weather"));
} else {
doc = docBuilder.parse(new File(FileName));
}
Element rootElement = doc.getDocumentElement();
Element weatherElement;
NodeList weatherNodes = doc.getDocumentElement().getElementsByTagName(strCity);
if (weatherNodes.getLength() > 0) {
weatherElement = (Element) weatherNodes.item(0);
} else {
weatherElement = doc.createElement(strCity);
rootElement.appendChild(weatherElement);
}
Element dateElement = doc.createElement("Date");
weatherElement.appendChild(dateElement);
Attr attr = doc.createAttribute("id");
attr.setValue(strDate);
dateElement.setAttributeNode(attr);
Element forecast = doc.createElement("forecast");
forecast.appendChild(doc.createTextNode(strforecast));
dateElement.appendChild(forecast);
Element mindegrees = doc.createElement("mindegrees");
mindegrees.appendChild(doc.createTextNode(strminDegrees));
dateElement.appendChild(mindegrees);
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(FileName));
transformer.transform(source, result);
} catch (Exception ex) {
ex.printStackTrace();
}
}

To modify how you update the document structure for DOM,
modify
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("Weather");
doc.appendChild(rootElement);
Element weatherElement = doc.createElement(strCity);
rootElement.appendChild(weatherElement);
to
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("Weather");
doc.appendChild(rootElement);
NodeList weatherNodes = rootElement.getElementsByTagName(strCity);// do we already have node?
Element weatherElement;
if(weatherNodes.getLength() > 0){ // if so reuse
weatherElement = (Element) weatherNodes.item(0);
}else { // else create
weatherElement = doc.createElement(strCity);
rootElement.appendChild(weatherElement);
}
Be aware the DOM is really intended for small documents if this is going to get very large
you will need to look at something like STaX.

If XML file already exists you should parse it and update the city if it already exists or add otherwise. Then rewrite XML.
DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc;
File file = new File(FileName);
if (!file.exists()) {
doc = docBuilder.newDocument();
doc.appendChild(doc.createElement("Weather"));
} else {
doc = docBuilder.parse(file);
}
Element rootElement = doc.getDocumentElement();
Element weatherElement = createWeatherElement(strCity, strDate, strforecast, strminDegrees, doc);
NodeList weatherNodes = doc.getDocumentElement().getElementsByTagName(strCity);
if (weatherNodes.getLength() > 0) {
rootElement.replaceChild(weatherElement, weatherNodes.item(0));
} else {
rootElement.appendChild(weatherElement);
}
Transformer transformer = transformerFactory.newTransformer();
...
private Element createWeatherElement(String strCity, String strDate, String strforecast, String strminDegrees, Document doc) {
Element rootElement = doc.getDocumentElement();
Element weatherElement = doc.createElement(strCity);
...
return weatherElement;
}