Develop Reference

Parser to parse unknown XML Schema in java

I tried understanding all other answers in stackoverflow.But I am not able to relate those answers to my question.
When I call a web service, I get response. I get schema by response.getData();(The XML of the data table containing the results.) (return type String). We don't know what data we get in that XML.
I need to use a 3rd party parser, so that when I give the above string to one method in that parser it should return all the elements in that XML and then I can print the required elements.
I don't want to start parsing the XML myself. Is there a way I can do this? (Does it even make any sense?). Sorry If I am totally wrong. (using Axis2/eclipse) (Edited)
Edit: Adding the code I've tried already.
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
NodeList nodeList = null;
try {
String xml = res2.getResult().getRawData();
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.parse(new ByteArrayInputStream(xml.getBytes()));
nodeList = document.getElementsByTagName("PhoneNumber");
NamedNodeMap attrib = document.getAttributes();
for (int i = 0; i < attrib.getLength(); i++) {
String nodeName = attrib.item(i).getNodeName();
//nodeName
String nodeValue = attrib.item(i).getNodeValue();
}
But I am not sure if the PhoneNumber is with that tag or other name. Also we don't know how many tags we have.
Thanks, Using the code by SyamS, I am able to print all the nodes and corresponding values from xml. Now I want to store that into a hashmap with key as node name and node values in a list.
Example XML :
<Docs>
<Doc>
<Id>12</Id>
<Phone>1234</Phone>
</Doc>
<Doc>
<Id>147</Id>
<Phone>12345</Phone>
<Locked>false</Locked>
<BID>2</BID>
<DocId>8</DocId>
<Date>2014-02-04T12:18:50.063-07:00</Date>
<Urgent>false</Urgent>
</Doc>
</Docs>

You need not go for a third party library for this. you could simply identify all leaf nodes using xpath and read the value (as well as attributes). For example
public static Map<String, List<String>> parseXml(String xml) throws XMLStreamException {
StringBuilder content = null;
Map<String, List<String>> dataMap = new HashMap<>();
XMLInputFactory factory = XMLInputFactory.newInstance();
InputStream stream = new ByteArrayInputStream(xml.getBytes());
XMLStreamReader reader = factory.createXMLStreamReader(stream);
while (reader.hasNext()) {
int event = reader.next();
switch (event) {
case XMLStreamConstants.START_ELEMENT:
content = new StringBuilder();
break;
case XMLStreamConstants.CHARACTERS:
if (content != null) {
content.append(reader.getText().trim());
}
break;
case XMLStreamConstants.END_ELEMENT:
if (content != null) {
String leafText = content.toString();
if(dataMap.get(reader.getLocalName()) == null){
List<String> values = new ArrayList<>();
values.add(leafText);
dataMap.put(reader.getLocalName(), values);
} else {
dataMap.get(reader.getLocalName()).add(leafText);
}
}
content = null;
break;
case XMLStreamConstants.START_DOCUMENT:
break;
}
}
return dataMap;
}

You should read answers related to Best XML parser for Java. Using the example XML from Sample XML File (books.xml) which I've downloaded to a temp folder on my C: drive, you might use Java's native SAXParser library. Here's an example class you might use to iterate through all the elements in XML. Create the class in your project, and call its parse method as:
File xml = new File("c:/temp/books.xml");
MySaxParser sax = new MySaxParser(xml);
sax.parseXml();
This is the class you can copy into your project to try it out. Modify according to your needs, of course. The imports should direct you to the appropriate Java API pages such as Class SAXParser to begin with.
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class MySaxParser extends DefaultHandler {
private String absolutePathToXml = "";
public MySaxParser(File xml) {
absolutePathToXml = xml.getAbsolutePath();
}
/**
* Parses an XML file into memory
*/
public void parseXml() {
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
SAXParser parser = factory.newSAXParser();
parser.parse(absolutePathToXml, this);
} catch (ParserConfigurationException e) {
System.out.println("ParserConfigurationException: ");
e.printStackTrace();
} catch (SAXException e) {
System.out.println("SAXException: ");
e.printStackTrace();
} catch (IOException e) {
System.out.println("IOException: ");
e.printStackTrace();
}
}
/**
* Event: Parser starts reading an element
*/
#Override
public void startElement(String s1, String s2, String elementName, Attributes attributes)
throws SAXException {
//print an element's name
System.out.println("element: " + elementName);
//print all attributes for this element
for(int i = 0; i < attributes.getLength(); i++) {
System.out.println("attribute: " + attributes.getValue(i));
}
}
}

Java jdom xml parsing

it's my first day with java and I try to build a little xml parser for my websites, so I can have a clean look on my sitemaps.xml . The code I use is like that
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.net.URL;
import java.util.List;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
class downloadxml {
public static void main(String[] args) throws IOException {
String str = "http://www.someurl.info/sitemap.xml";
URL url = new URL(str);
InputStream is = url.openStream();
int ptr = 0;
StringBuilder builder = new StringBuilder();
while ((ptr = is.read()) != -1) {
builder.append((char) ptr);
}
String xml = builder.toString();
org.jdom2.input.SAXBuilder saxBuilder = new SAXBuilder();
try {
org.jdom2.Document doc = saxBuilder.build(new StringReader(xml));
System.out.println(xml);
Element xmlfile = doc.getRootElement();
System.out.println("ROOT -->"+xmlfile);
List list = xmlfile.getChildren("url");
System.out.println("LIST -->"+list);
} catch (JDOMException e) {
// handle JDOMExceptio n
} catch (IOException e) {
// handle IOException
}
System.out.println("===========================");
}
}
When the code pass
System.out.println(xml);
I get a clean print of the xml sitemap. When it comes to:
System.out.println("ROOT -->"+xmlfile);
Output:
ROOT -->[Element: <urlset [Namespace: http://www.sitemaps.org/schemas/sitemap/0.9]/>]
It also finds the root element. But for some reason or another, when the script should go for the childs, it return an empty print:
System.out.println("LIST -->"+list);
Output:
LIST -->[]
What should I do in another way? Any pointers to get the childs?
The XML looks like this
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:image="http://www.google.com/schemas/sitemap-image/1.1">
<url>
<loc>http://www.image.url</loc>
<image:image>
<image:loc>http://www.image.url/image.jpg</image:loc>
</image:image>
<changefreq>daily</changefreq>
</url>
<url>
</urlset>

You've come a long way in a day.
Short answer, you are ignoring the namespace of your XML Document. Change the line:
List list = xmlfile.getChildren("url");
to
Namespace ns = Namespace.getNamespace("http://www.sitemaps.org/schemas/sitemap/0.9");
List list = xmlfile.getChildren("url", ns);
For your convenience, you may also want to simplify the whole build process to:
org.jdom2.Document doc = saxBuilder.build("http://www.someurl.info/sitemap.xml");

My comment is similar to the above, but with the catch clauses, that display nice messages when the input xml is not "well-formed". The input here is an xml file.
File file = new File("adr781.xml");
SAXBuilder builder = new SAXBuilder(false);
try {
Document doc = builder.build(file);
Element root = doc.getRootElement();
} catch (JDOMException e) {
say(file.getName() + " is not well-formed.");
say(e.getMessage());
} catch (IOException e) {
say("Could not check " + file.getAbsolutePath());
say(" because " + e.getMessage());
}

How to append xml file in java

I've been using xml files to save data from my java program. I'm using the java DOM api. I want to add to the document by adding an element and then adding children to that element.
I tried doing it using this code but when i run it it does nothing. Is there another way of doing it that would be simple and work better? is there a way i can get this code working?
File file = new File("C:/users/peter/desktop/newxml.xml");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.parse(file);
Element newB = document.createElement("B");
Element newC = document.createElement("c");
newC.setTextContent("11");
Element newD = document.createElement("d");
newD.setTextContent("21");
Element newE = document.createElement("e");
newE.setTextContent("31");
newB.appendChild(newC);
newB.appendChild(newD);
newB.appendChild(newE);
document.getDocumentElement().appendChild(newB);

This java code works to append new node to the xml file......it is based on DOM
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.FileOutputStream;
public class writexml1 {
public static void main (String args[])
{
File docFile = new File("..\\jquery\\WebContent\\demo\\testing.xml");
Document doc = null;
try
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(docFile);
}
catch (java.io.IOException e)
{
System.out.println("Can't find the file");
}
catch (Exception e)
{
System.out.print("Problem parsing the file.");
}
Element root = doc.getDocumentElement();
System.out.println("The root element is " + root.getNodeName() + ".\n");
NodeList children = root.getChildNodes();
System.out.print("There are "+children.getLength()+" child elements.\n");
System.out.print("They are: \n");
//Print the file
for (Node child = root.getFirstChild();child != null;child = child.getNextSibling())
{
if (child.getNodeType() == child.TEXT_NODE)
{
System.out.println("Text: "+child.getNodeValue());
}
else if (child.getNodeType() == child.ELEMENT_NODE)
{
System.out.println(child.getNodeName()+" = "+child.getFirstChild().getNodeValue());
}
}
//NodeList deleteElement = root.getElementsByTagName("staff");
//Node deleteNode= deleteElement.item(0);
//root.removeChild(deleteNode);
Element staffElement = doc.createElement("staff");
Node updateText = doc.createTextNode("");
staffElement.appendChild(updateText);
//
Element firstName = doc.createElement("firstname");
String str_firstName="added firstname";
Node firstNameNode = doc.createTextNode(str_firstName);
firstName.appendChild(firstNameNode);
staffElement.appendChild(firstName);
//
Element lastName = doc.createElement("lastname");
String str_lastName="added lastname";
Node lastNameNode = doc.createTextNode(str_lastName);
lastName.appendChild(lastNameNode);
staffElement.appendChild(lastName);
//
Element nickName = doc.createElement("nickname");
String str_nickName="added nickname";
Node nickNameNode = doc.createTextNode(str_nickName);
nickName.appendChild(nickNameNode);
staffElement.appendChild(nickName);
//
Element salary = doc.createElement("salary");
String str_salary="$10,000";
Node salaryNode = doc.createTextNode(str_salary);
salary.appendChild(salaryNode);
staffElement.appendChild(salary);
//
root.appendChild(staffElement);
//Node StaffNode=(Node)updateElement;
try{
String outputURL = "..\\jquery\\WebContent\\demo\\testing.xml";
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new FileOutputStream(outputURL));
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer = transFactory.newTransformer();
transformer.transform(source, result);
} catch (Exception e) {
e.printStackTrace();
}
}
}

you should check out the JAXB API. If I understand right, you're xml looks like this:
<B>
<C>11</C>
<D>21</D>
<E>31</E>
</B>
So code would be:
import javax.xml.bind.JAXBContext;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
#XmlRootElement
#XmlAccessorType(XmlAccessType.FIELD)
public class B {
#XmlElement public String C; // sloppy, probably should be type Integer or something
#XmlElement public String D;
#XmlElement public String E;
}
// then, somewhere else in your code you want to serialize...
B b = new B();
b.C = "11";
b.D = "21";
b.E = "31";
JAXBContext c = JAXBContext.newInstance(B.class);
// where w is a Writer instance
c.createMarshaller().marshal(b, w);

Create XML file using java

How to create a xml file and save it in some place in my machine using java..there are attributes also include in the xml file? I have found org.w3c.dom.Document but having problems with creating attributes for elements and save the xml file.
Thank You.

You can use a DOM XML parser to create an XML file using Java. A good example can be found on this site:
try {
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
//root elements
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("company");
doc.appendChild(rootElement);
//staff elements
Element staff = doc.createElement("Staff");
rootElement.appendChild(staff);
//set attribute to staff element
Attr attr = doc.createAttribute("id");
attr.setValue("1");
staff.setAttributeNode(attr);
//shorten way
//staff.setAttribute("id", "1");
//firstname elements
Element firstname = doc.createElement("firstname");
firstname.appendChild(doc.createTextNode("yong"));
staff.appendChild(firstname);
//lastname elements
Element lastname = doc.createElement("lastname");
lastname.appendChild(doc.createTextNode("mook kim"));
staff.appendChild(lastname);
//nickname elements
Element nickname = doc.createElement("nickname");
nickname.appendChild(doc.createTextNode("mkyong"));
staff.appendChild(nickname);
//salary elements
Element salary = doc.createElement("salary");
salary.appendChild(doc.createTextNode("100000"));
staff.appendChild(salary);
//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:\\testing.xml"));
transformer.transform(source, result);
System.out.println("Done");
}catch(ParserConfigurationException pce){
pce.printStackTrace();
}catch(TransformerException tfe){
tfe.printStackTrace();
}

You can use Xembly, a small open source library that makes this XML creating process much more intuitive:
String xml = new Xembler(
new Directives()
.add("root")
.add("order")
.attr("id", "553")
.set("$140.00")
).xml();
Xembly is a wrapper around native Java DOM, and is a very lightweight library (I'm the author).

Have look at dom4j or jdom. Both libraries allow creating a Document and allow printing the document as xml. Both are widly used, pretty easy to use and you'll find a lot of examples and snippets.
dom4j - Quick start guide

Just happened to work at this also, use https://www.tutorialspoint.com/java_xml/java_dom_create_document.htm the example from here, and read the explanations. Also I provide you my own example:
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.newDocument();
// root element
Element rootElement = doc.createElement("words");
doc.appendChild(rootElement);
while (ptbt.hasNext()) {
CoreLabel label = ptbt.next();
System.out.println(label);
m = r1.matcher(label.toString());
//System.out.println(m.find());
if (m.find() == true) {
Element w = doc.createElement("word");
w.appendChild(doc.createTextNode(label.toString()));
rootElement.appendChild(w);
}
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File("C:\\Users\\workspace\\Tokenizer\\tokens.xml"));
transformer.transform(source, result);
// Output to console for testing
StreamResult consoleResult = new StreamResult(System.out);
transformer.transform(source, consoleResult);
This is in the context of using the tokenizer from Stanford for Natural Language Processing, just a part of it to make an idea on how to add elements.
The output is: Billbuyedapples (I've read the sentence from a file)

I am providing an answer from my own blog. Hope this will help.
What will be output?
Following XML file named users.xml will be created.
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<users>
<user uid="1">
<firstname>Interview</firstname>
<lastname>Bubble</lastname>
<email>admin#interviewBubble.com</email>
</user>
</users>
PROCEDURE
Basic steps, in order to create an XML File with a DOM Parser, are:
Create a DocumentBuilder instance.
Create a Document from the above DocumentBuilder.
Create the elements you want using the Element class and its appendChild method.
Create a new Transformer instance and a new DOMSource instance.
Create a new StreamResult to the output stream you want to use.
Use transform method to write the DOM object to the output stream.
SOURCE CODE:
package com.example.TestApp;
import java.io.File;
import java.io.IOException;
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;
public class CreateXMLFileJava {
public static void main(String[] args) throws ParserConfigurationException,
IOException,
TransformerException
{
// 1.Create a DocumentBuilder instance
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dbuilder = dbFactory.newDocumentBuilder();
// 2. Create a Document from the above DocumentBuilder.
Document document = dbuilder.newDocument();
// 3. Create the elements you want using the Element class and its appendChild method.
// root element
Element users = document.createElement("users");
document.appendChild(users);
// child element
Element user = document.createElement("user");
users.appendChild(user);
// Attribute of child element
user.setAttribute("uid", "1");
// firstname Element
Element firstName = document.createElement("firstName");
firstName.appendChild(document.createTextNode("Interview"));
user.appendChild(firstName);
// lastName element
Element lastName = document.createElement("lastName");
lastName.appendChild(document.createTextNode("Bubble"));
user.appendChild(lastName);
// email element
Element email = document.createElement("email");
email.appendChild(document.createTextNode("admin#interviewBubble.com"));
user.appendChild(email);
// write content into xml file
// 4. Create a new Transformer instance and a new DOMSource instance.
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(document);
// 5. Create a new StreamResult to the output stream you want to use.
StreamResult result = new StreamResult(new File("/Users/admin/Desktop/users.xml"));
// StreamResult result = new StreamResult(System.out); // to print on console
// 6. Use transform method to write the DOM object to the output stream.
transformer.transform(source, result);
System.out.println("File created successfully");
}
}
OUTPUT:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<users>
<user uid="1">
<firstName>Interview</firstName>
<lastName>Bubble</lastName>
<email>admin#interviewBubble.com</email>
</user>
</users>

You might want to give XStream a shot, it is not complicated. It basically does the heavy lifting.

I liked the Xembly syntax, but it is not a statically typed API. You can get this with XMLBeam:
// Declare a projection
public interface Projection {
#XBWrite("/root/order/#id")
Projection setID(int id);
#XBWrite("/root/order")
Projection setValue(String value);
}
public static void main(String[] args) {
// create a projector
XBProjector projector = new XBProjector();
// use it to create a projection instance
Projection projection = projector.projectEmptyDocument(Projection.class);
// You get a fluent API, with java types in parameters
projection.setID(553).setValue("$140.00");
// Use the projector again to do IO stuff or create an XML-string
projector.toXMLString(projection);
}
My experience is that this works great even when the XML gets more complicated. You can just decouple the XML structure from your java code structure.

package com.server;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import org.w3c.dom.*;
import com.gwtext.client.data.XmlReader;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
public class XmlServlet extends HttpServlet
{
NodeList list;
Connection con=null;
Statement st=null;
ResultSet rs = null;
String xmlString ;
BufferedWriter bw;
String displayTo;
String displayFrom;
String addressto;
String addressFrom;
Date send;
String Subject;
String body;
String category;
Document doc1;
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
System.out.print("on server");
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
System.out.print("on server");
try
{
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = builderFactory.newDocumentBuilder();
//creating a new instance of a DOM to build a DOM tree.
doc1 = docBuilder.newDocument();
new XmlServlet().createXmlTree(doc1);
System.out.print("on server");
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
public void createXmlTree(Document doc) throws Exception {
//This method creates an element node
System.out.println("ruchipaliwal111");
try
{
System.out.println("ruchi111");
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3308/plz","root","root1");
st = con.createStatement();
rs = st.executeQuery("select * from data");
Element root = doc.createElement("message");
doc.appendChild(root);
while(rs.next())
{
displayTo=rs.getString(1).toString();
System.out.println(displayTo+"getdataname");
displayFrom=rs.getString(2).toString();
System.out.println(displayFrom +"getdataname");
addressto=rs.getString(3).toString();
System.out.println(addressto +"getdataname");
addressFrom=rs.getString(4).toString();
System.out.println(addressFrom +"getdataname");
send=rs.getDate(5);
System.out.println(send +"getdataname");
Subject=rs.getString(6).toString();
System.out.println(Subject +"getdataname");
body=rs.getString(7).toString();
System.out.println(body+"getdataname");
category=rs.getString(8).toString();
System.out.println(category +"getdataname");
//adding a node after the last child node of ssthe specified node.
Element element1 = doc.createElement("Header");
root.appendChild(element1);
Element child1 = doc.createElement("To");
element1.appendChild(child1);
child1.setAttribute("displayNameTo",displayTo);
child1.setAttribute("addressTo",addressto);
Element child2 = doc.createElement("From");
element1.appendChild(child2);
child2.setAttribute("displayNameFrom",displayFrom);
child2.setAttribute("addressFrom",addressFrom);
Element child3 = doc.createElement("Send");
element1.appendChild(child3);
Text text2 = doc.createTextNode(send.toString());
child3.appendChild(text2);
Element child4 = doc.createElement("Subject");
element1.appendChild(child4);
Text text3 = doc.createTextNode(Subject);
child4.appendChild(text3);
Element child5 = doc.createElement("category");
element1.appendChild(child5);
Text text44 = doc.createTextNode(category);
child5.appendChild(text44);
Element element2 = doc.createElement("Body");
root.appendChild(element2);
Text text1 = doc.createTextNode(body);
element2.appendChild(text1);
/*
Element child1 = doc.createElement("name");
root.appendChild(child1);
Text text = doc.createTextNode(getdataname);
child1.appendChild(text);
Element element = doc.createElement("address");
root.appendChild(element);
Text text1 = doc.createTextNode( getdataaddress);
element.appendChild(text1);
*/
}
//TransformerFactory instance is used to create Transformer objects.
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.METHOD,"xml");
// transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "3");
// create string from xml tree
StringWriter sw = new StringWriter();
StreamResult result = new StreamResult(sw);
DOMSource source = new DOMSource(doc);
transformer.transform(source, result);
xmlString = sw.toString();
File file = new File("./war/ds/newxml.xml");
bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file)));
bw.write(xmlString);
}
catch(Exception e)
{
System.out.print("after while loop exception"+e.toString());
}
bw.flush();
bw.close();
System.out.println("successfully done.....");
}
}

How can I append an attribute to an existing XML element in Java?

I want to append an attribute an existing element in XML using Java. For example:
<employee>
<details name="Jai" age="25"/>
<details name="kishore" age="30"/>
</employee>
It want to add weight to it (assume that it is calculated and then appended in response). How can I append that to all items?
<details name="Jai" age="25" weight="55"/>

import org.w3c.dom.*;
import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
public class AddAndPrint {
public static void main(String[] args) {
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse("/path/to/file.xml");
NodeList employees = document.getElementsByTagName("employee");
for (Node employee : employees) {
for (Node child : employee.getChildNodes() {
if ("details".equals(child.getNodeName()) child.setAttribute("weight", "150");
}
}
try {
Source source = new DOMSource(doc);
StringWriter stringWriter = new StringWriter();
Result result = new StreamResult(stringWriter);
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer();
transformer.transform(source, result);
System.out.println(stringWriter.getBuffer().toString());
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
}
}
}

Here is a quick solution based on jdom:
public static void main(String[] args) throws JDOMException, IOException {
File xmlFile = new File("employee.xml");
SAXBuilder builder = new SAXBuilder();
Document build = builder.build(xmlFile);
XPath details = XPath.newInstance("//details");
List<Element> detailsNodes = details.selectNodes(build);
for (Element detailsNode:detailsNodes) {
detailsNode.setAttribute("weight", "70"); // static weight for demonstration
}
XMLOutputter outputter = new XMLOutputter(Format.getPrettyFormat());
outputter.output(build, System.out);
}
First, we build a document (SAXBuilder), next we create a XPath expression for the details node, then we iterate through the elements for that expression and add the weight attribute.
The last two lines just verify that it's white magic :-)