Append node to an existing xml-Java

Question

I have seen the same question being answered for vb and c#, but i need a Java best solution for appending nodes to an xml. Will xpath help? I have

<A>
  <B>
    <c>1<c/>
    <d>2<d/>
    <e>3<e/>
  </B>
  <B>
    <c>1<c/>
    <d>2<d/>
    <e>3<e/>
  </B>
</A>

Need to append another

<B>
   <c>11<c/>
   <d>21<d/>
   <e>31<e/>
</B>

Jon Skeet · Accepted Answer · 2009-09-16 06:48:56Z

13

XPath will help you to find nodes, but not really append them. I don't think you'd find it particularly useful here.

Which XML API are you using? If it's the W3C DOM (urgh) then you'd do something like:

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);

edited Sep 16, 2009 at 6:48

answered Sep 16, 2009 at 6:21

Jon Skeet

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5 Comments

Jon Skeet Over a year ago

Editing... although if you wanted to see how to create content within those elements, it would have been useful to say so in the question.

JWiley Over a year ago

I see this is an ancient post, but in reference to your "urgh," what XML API would you prefer over the W3C DOM and why is it so "urghly" so to say?

Jon Skeet Over a year ago

@jdwilemo: The W3C DOM API is really ugly, IMO - it's full of factories of factories etc, construction doesn't encourage code which follows the eventual structure of the document etc. Compared with something like LINQ to XML in .NET, it's absolutely horrible.

JWiley Over a year ago

@JonSkeet: I see, thanks for the reply. But what about in Java? Is there another API I could use in substitution of the W3C?

Jon Skeet Over a year ago

@jdwilemo: Various - you might want to look at JDom to start with: jdom.org

Winston Chen · Accepted Answer · 2009-09-16 06:26:53Z

2

The most strait-forward way is that you parse, using Sax or Dom, all the files into a data structure, for example an A class which has a B class with members of C,D,E class in your case.

And output the data structure back to XML.

answered Sep 16, 2009 at 6:26

Winston Chen

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Comments

2 revs, 2 users 91% · Accepted Answer · 2009-09-25 21:24:55Z

0

You may want to use XMLModier of vtd-xml to do it in a cool way, which is to append the byte content directly... You just need to call XMLModier's insertAfterElement()... below is a link to the code sample: Incrementally Modify XML in Java:

import com.ximpleware.*;
import java.io.*;

public class ModifyXML {
     public static void main(String[] s) throws Exception{
        VTDGen vg = new VTDGen(); // Instantiate VTDGen
        XMLModifier xm = new XMLModifier(); //Instantiate XMLModifier
        if (vg.parseFile("old.xml",false)){
             VTDNav vn = vg.getNav();
             xm.bind(vn);

             // first update the value of attr
             int i = vn.getAttrVal("attr");
             if (i!=-1){
                  xm.updateToken(i,"value");
             }

             // navigate to <a>
            if (vn.toElement(VTDNav.FC,"a")) {
                  // update the text content of <a>
                   i=vn.getText();
                   if (i!=-1){
                      xm.updateToken(i," new content ");
                   }
                   // insert an element before <a> (which is the cursor element)
                   xm.insertBeforeElement("<b/>\n\t");

                   // insert an element after <a> (which is the cursor element)
                   xm.insertAfterElement("\n\t<c/>");
            }

            xm.output(new FileOutputStream("new.xml"));
         }
     }

}

edited Sep 25, 2009 at 21:24

community wiki

2 revs, 2 users 91%
John Saunders

4 Comments

John Saunders Over a year ago

Would you mind adding why this is a cool way? It sounds the opposite of anything I've ever heard of. Also, why is this answer Community Wiki?

vtd-xml-author Over a year ago

it is cool because it is directly byte level append, as opposed to data strcuture level append... I think I explained that in my post... "append byte content"

John Saunders Over a year ago

Yes, you just didn't say why byte level append is cool, and not simply a bad idea that makes the code dependent on the encoding of the XML document.

John Saunders Over a year ago

And you didn't answer why you feel this answer should be CW when the question is not, and none of the other answers are. Please see meta.stackexchange.com/questions/7931/… about CW.

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