Changes to XML file

Question

Hello,
I have a XML file and I need to apply chnges to an attribute and save the xml file (using JDom).
How do I do it? , I've looked all over for an example for this simple problem but did not find it ( I've wrote the part of reading from the Xml and now I'm stuck on the writing).
Thanks for you're help folks !

Answer 1

Here is an example of using XMLwriter and DataWriter.
I use the "crimson" XML implementation wich you can download at http://xml.apache.org/dist/crimson/ :
download the file "crimson-1.1.3-bin.zip"
and extract the file "crimson.jar" to "C:\Program Files\Java\jdk1.5.0_01\jre\lib\ext" or to where is your "..\jre\lib".
My example consists of three files :
1. TestXML is the main class
2. ConfigHandler is an interface
3. HandleConfig processes the XML file (a simple configuration file)
* TestXML.java
* Created on 14 f�vrier 2005, 02:05
import java.io.File;
import java.util.HashMap;
import javax.swing.*;
* @author Andr� Uhres
public class TestXML extends javax.swing.JFrame implements ConfigHandler{
    /** Creates a new instance of TestXML */
    public TestXML() {
        initComponents();
        getConfig();
        jButton2.getRootPane().setDefaultButton(jButton2);
        path.setText(pathUser);
    private void initComponents() {       
        setTitle("Test XML");
        jPanel1 = new javax.swing.JPanel();
        jToolBar1 = new javax.swing.JToolBar();
        jButton2 = new javax.swing.JButton();
        path = new JTextField(pathUser);
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jPanel1.setLayout(null);
        getContentPane().add(jPanel1, java.awt.BorderLayout.CENTER);
        jButton2.setText("Update");
        jButton2.setMaximumSize(new java.awt.Dimension(60, 20));
        jButton2.setPreferredSize(new java.awt.Dimension(60, 20));
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
        jToolBar1.add(jButton2);
        jToolBar1.add(path);
        getContentPane().add(jToolBar1, java.awt.BorderLayout.NORTH);
        java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
        setBounds((screenSize.width-400)/2, (screenSize.height-300)/2, 400, 300);
    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                        
        pathUser = path.getText();
        updateConfig();
    /** Sets the configuration values
     * @param keyWord identifies the configuration value
     * @param keyValue gives the new configuration value
    public void setConfigValues(String keyWord, String keyValue){
        if(keyWord.equalsIgnoreCase("PathUser"))pathUser=keyValue;
    public HashMap getConfigValues(){
        HashMap configValues = new HashMap();
        configValues.put("PathUser", pathUser);
        return configValues;
    public HashMap getDefaultConfigValues() {
        HashMap configValues = new HashMap();
        configValues.put("PathUser", "\\\\prdfs2\\data\\WGRP\\AFSOUT\\");
        return configValues;
    public synchronized void getConfig(){
        File balag = new File("c:\\balageeConf");
        if(!balag.exists())
            balag.mkdir();
        argv2=new String[]{
            "C:\\balageeConf\\balagee_config.xml"
        new HandleConfig(argv2, this, null);
    public synchronized void updateConfig(){
        new HandleConfig(argv2, this, getConfigValues());    //update file
    public static void main(String args[]) {
        new TestXML().setVisible(true);
    private String pathUser;
    private String[] argv2;
    private javax.swing.JButton jButton2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JToolBar jToolBar1;
    private javax.swing.JTextField path;
* ConfigHandler .java
* Created on 17 juillet 2004, 07:34
import java.util.*;
* @author  andreuhres
public interface ConfigHandler {
    /** <B>
     * Use: at program initialisation !<br>Example:</B>
     * <br><CODE>public void synchronized getConfig(){
     * <br>        File balag = new File("c:\\balageeConf");
     * <br>        if(!balag.exists())
     * <br>            balag.mkdir();
     * <br>        argv2=new String[]{
     * <br>            "C:\\balageeConf\\balagee_config.xml"
     * <br>        };
     * <br>        new HandleConfig(argv2, this, null);
     * <br>    }
     * </CODE>
    void getConfig();
    /** <B>
     * Use: internal in HandleConfig() !<br>Example:
     * </B><br><CODE>public void setConfigValues(String keyWord, String keyValue){
     * <br>        if(keyWord.equalsIgnoreCase("PathUser"))pathUser=keyValue;
     * <br>        if(keyWord.equalsIgnoreCase("SelectedFile")){
     * <br>            keyValue=keyValue.toLowerCase().replaceFirst(".csv", ".bag");
     * <br>            defaultFournisseur=keyValue;
     * <br>            lastFournisseur=keyValue;
     * <br>        }
     * <br>        if(keyWord.equalsIgnoreCase("optionShift")){
     * <br>            optionShift=Boolean.valueOf(keyValue).booleanValue();
     * <br>        }
     * <br>        if(keyWord.equalsIgnoreCase("nePlusAfficher")){
     * <br>            nePlusAfficher=Boolean.valueOf(keyValue).booleanValue();
     * <br>        }
     * <br>        if(keyWord.equalsIgnoreCase("nePlusAfficher2")){
     * <br>            nePlusAfficher2=Boolean.valueOf(keyValue).booleanValue();
     * <br>        }
     * <br>        if(keyWord.equalsIgnoreCase("nePlusAfficher3")){
     * <br>            nePlusAfficher3=Boolean.valueOf(keyValue).booleanValue();
     * <br>        }
     * <br>
     * <br>        if(keyWord.equalsIgnoreCase("initChooser")){
     * <br>            initChooser=Boolean.valueOf(keyValue).booleanValue();
     * <br>        }
     * <br>    }
     * </CODE>
    void setConfigValues(String keyWord, String keyValue);
    /** <B>
     * Use: in updateConfig() !<br>Example:
     * </B><br><CODE>
     *     public HashMap getConfigValues(){
     * <br>         HashMap configValues = new HashMap();
     * <br>         configValues.put("PathUser", pathUser);
     * <br>         configValues.put("SelectedFile", lastFournisseur);
     * <br>         configValues.put("optionShift", ""+optionShift);
     * <br>         configValues.put("nePlusAfficher", ""+nePlusAfficher);
     * <br>         configValues.put("nePlusAfficher2", ""+nePlusAfficher2);
     * <br>         configValues.put("nePlusAfficher3", ""+nePlusAfficher3);
     * <br>         configValues.put("initChooser", ""+initChooser);
     * <br>         return configValues;
     * <br>     }
     * </CODE>
    HashMap getConfigValues();
    /** <B>
     * Use: internal in HandleConfig() !<br>Example:
     * </B>
     * <br><CODE>public HashMap getDefaultConfigValues() {
     * <br>        HashMap configValues = new HashMap();
     * <br>        configValues.put("PathUser", "W:\\WGRP\\AFSOUT\\");
     * <br>        if(System.getProperty("user.name").toUpperCase().equals("ANDREUHRES"))
     * <br>            configValues.put("PathUser", "C:\\balag\\balageeData\\");
     * <br>        configValues.put("SelectedFile", "bc090404.bag");
     * <br>        configValues.put("optionShift", "false");
     * <br>        configValues.put("nePlusAfficher", "false");
     * <br>        configValues.put("nePlusAfficher2", "false");
     * <br>        configValues.put("nePlusAfficher3", "false");
     * <br>        configValues.put("initChooser", "false");
     * <br>        return configValues;
     * <br>    }
     * </CODE>
    HashMap getDefaultConfigValues();
    /** <B>
     * Use: at program exit !<br>Example:
     * </B>
     * <br><CODE>public void synchronized updateConfig(){
     * <br>        new HandleConfig(argv2, this, getConfigValues());    //update file
     * <br>    }
     * </CODE>
    void updateConfig();
import java.io.*;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map.Entry;
import javax.swing.JFrame;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.apache.crimson.jaxp.DocumentBuilderFactoryImpl;
import org.apache.crimson.tree.XmlDocument;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.helpers.AttributesImpl;
/* Usage:
        argv2=new String[]{
            "C:\\balageeConf\\balagee_config.xml"
        new HandleConfig(argv2, this, null);    //process file
        new HandleConfig(argv2, this, getConfigValues());    //update file
public class HandleConfig {
    /** Number of elements in document before modification. */
    protected int m_elements;
    /** Number of whitespace content segments deleted from document. */
    protected int m_deletes;
    /** Number of elements added wrapping content. */
    protected int m_adds;
    final ConfigHandler ConfigHandler;
    String[]argv2;
    HashMap configValues;
    HashMap confValues;
     * @param argv file name (full path) defined as the only element of the String array
     * @param parent reference to the calling object (= this)
     * @param configValues null (for initialisation) or reference to a hashmap containing keyword-value pairs (for update)
    public HandleConfig(String[] argv, JFrame parent, HashMap configValues){
        this.ConfigHandler=(ConfigHandler)parent;
        this.configValues=configValues;
        argv2=argv;
        File config02 = new File(argv2[0]);
        String confTest ="";
        try{
            BufferedReader readerConf = new BufferedReader(new FileReader(config02));
            confTest = readerConf.readLine();
            readerConf.close();
            if (confTest==null){
                config02.delete();
        }catch(Exception ex){
            ex.printStackTrace();
        runIt(argv2);
     * Read contents of file into byte array.
     * @param path file path
     * @return array of bytes containing all data from file
     * @throws IOException on file access error
    private static byte[] getFileBytes(String path) throws IOException {
        File file = new File(path);
        int length = (int)file.length();
        byte[]data = new byte[length];
        FileInputStream in = new FileInputStream(file);
        int offset = 0;
        do {
            offset += in.read(data, offset, length-offset);
        } while (offset < data.length);
        return data;
     * Driver, reads the input files and executes the processing
     * code.
     * @param argv command line arguments
    protected void runIt(String[] argv) {
        // handle list of files to be used
        if (argv.length > 0) {
            // make sure we have a non-empty file name
            String path = argv[0].trim();
            if (path.length() > 0) {
                // read file data into byte array
                byte[] data = null;
                try {
                    data = getFileBytes(path);
                } catch (IOException ex) {
                    // file does not exist: create file
                    try{
                        confValues = ConfigHandler.getDefaultConfigValues();
                        Iterator it = confValues.entrySet().iterator();
                        while(it.hasNext()){
                            Entry entry = (Entry)(it.next());
                            String key = (String)entry.getKey();
                            String value = (String)entry.getValue();
                            ConfigHandler.setConfigValues(key, value);
                        createConfig(path);
                        return;
                    }catch(Exception ex1){
                        System.err.println("Error reading file " + path + ':');
                        ex.printStackTrace(System.err);
                        return;
                // process file data
                try {
                    ByteArrayInputStream  in  = new ByteArrayInputStream(data);
                    //                    ByteArrayOutputStream out = new ByteArrayOutputStream(data.length);
                    FileOutputStream out = new FileOutputStream(path);
                    m_elements = 0;
                    m_deletes = 0;
                    m_adds = 0;
                    newElement=false;
                    processFile(in, out);
                    System.out.println(' ' + path + ": " + m_elements +" elements ");
                    confValues = ConfigHandler.getConfigValues();
                    if( m_elements <= confValues.size() ) {
                        createConfig(path);
                    //                    FileOutputStream fos = new FileOutputStream(path);
                    //                    fos.write(out.toByteArray());
                    //                    fos.close();
                } catch (Exception ex) {
                    ex.printStackTrace(System.err);
                    return;
        } else {
            System.err.println("No document files specified");
    boolean newElement=false;
    protected void createConfig(String path) {
        try{
            DataWriter w = new DataWriter();
            FileWriter writer = new FileWriter(path);
            AttributesImpl attrList=new AttributesImpl();
            w.setOutput(writer);
            w.setIndentStep(3);
            w.startDocument();
            w.startElement("config");
            confValues = ConfigHandler.getConfigValues();
            Iterator it = confValues.entrySet().iterator();
            boolean first=true;
            while(it.hasNext()){
                Entry entry = (Entry)(it.next());
                String key = (String)entry.getKey();
                String value = (String)entry.getValue();
                if(first){
                    first=false;
                    attrList.addAttribute("","key","","", key);
                }else{
                    attrList.setAttribute(0,"","key","","", key);
                w.dataElement("", "configItem", "", attrList, value);
            w.endElement("config");
            w.endDocument();
            System.out.println("File created: "+path);
        }catch(Exception ex){
            ex.printStackTrace();
    protected void processElement(Element element) {
        // loop through child nodes
        Node child;
        Node next = (Node)element.getFirstChild();
        if(!newElement){
            while ((child = next) != null) {
                // set next before we change anything
                next = child.getNextSibling();
                // handle child by node type
                if (child.getNodeType() == Node.TEXT_NODE) {
                    // trim whitespace from content text
                    String trimmed = child.getNodeValue().trim();
                    if (trimmed.length() == 0) {
                        // delete child if nothing but whitespace
                        element.removeChild(child);
                }else if (child.getNodeType() == Node.ELEMENT_NODE) {
                    // handle child elements with recursive call
                    if(child.getNodeName().equalsIgnoreCase("configItem")){
                        if(configValues==null){
                            ConfigHandler.setConfigValues(((Element)child).getAttribute("key"),
                            child.getFirstChild().getNodeValue());
                        }else{
                            String key = ((Element)child).getAttribute("key");
                            String valueOld = child.getFirstChild().getNodeValue();
                            String valueNew = (String)configValues.get(key);
                            //                        System.out.println("key: "+key+" valueOld: "+valueOld+"  valueNew: "+valueNew);
                            if( !valueNew.equals(valueOld) ){
                                try{
                                    child.getFirstChild().setNodeValue(valueNew);
                                }catch(Exception ex){
                                    ex.printStackTrace();
                    processElement((Element)child);
                    m_elements++;
        }else{
            if ( (child = next)!=null && configValues!=null ) {
                next = child.getNextSibling();
                element.appendChild(next.cloneNode(false));
    protected void processFile(InputStream in, OutputStream out)
    throws Exception {
        // parse the document from input stream
        System.setProperty("javax.xml.parsers.DocumentBuilderFactory",
        "org.apache.crimson.jaxp.DocumentBuilderFactoryImpl");
        DocumentBuilderFactory dbf = DocumentBuilderFactoryImpl.newInstance();
        dbf.setNamespaceAware(true);
        DocumentBuilder builder = dbf.newDocumentBuilder();
        Document doc=null;
        doc = builder.parse(in);
        // recursively walk and process document
        m_elements++;
        processElement(doc.getDocumentElement());
        // write the document to output stream
        Writer  writer = new OutputStreamWriter(out, "ISO-8859-1");
        ((XmlDocument)doc).write(writer, "ISO-8859-1");
        /* See also: --> FileOutputStream fos in method runIt(argv)               */
    File tboConnOut = null;
}