CODEWITHSUNDEEP
javaxml
Aruna Karunarathna
Aruna Karunarathna

Reputation: 1021

How to write to an existing XML file using java

I've got an xml file looked like this. employees.xml

<Employees>
    <Employee>
        <FirstName>myFirstName</FirstName>
        <LastName>myLastName</LastName>
        <Salary>10000</Salary>
    <Employee>
</Employees>

Now how do I add new Employee elements to the existing XML file?.. An example code is highly appreciated.

Upvotes: 4

Views: 14178

Answers (5)

Don Roby
Don Roby

Reputation: 41165

To add to an existing XML file, you generally need to read it in to an internal data structure, add the needed data in the internal form and then write it all out again, overwriting the original file.

The internal structure can be DOM or one of your own making, and there are multiple ways of both reading it in and writing it out.

If the data is reasonably small, DOM is probably easiest, and there is some sample code in the answers to this related question.

If your data is large, DOM will not do. Possible approaches are to use SAX to read and write (though SAX is traditionally only a reading mechanism) as described in an answer to another related question.

You might also want to consider JAXB or (maybe even best) StAX.

Upvotes: 2

Francisco Spaeth
Francisco Spaeth

Reputation: 23913

I think this link can be useful for you.

Here you have samples how to read / parse, modify (add elements) and save (write to xml file again).

The following samples you can find at: http://www.petefreitag.com/item/445.cfm

Read:

DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse("/path/to/file.xml");

Modify:

// attributes
Node earth = doc.getFirstChild();
NamedNodeMap earthAttributes = earth.getAttributes();
Attr galaxy = doc.createAttribute("galaxy");
galaxy.setValue("milky way");
earthAttributes.setNamedItem(galaxy);

// nodes
Node canada = doc.createElement("country");
canada.setTextContent("ca");
earth.appendChild(canada);

Write XML file:

Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");

//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);

Upvotes: 2

bmargulies
bmargulies

Reputation: 100196

You can't 'write nodes to an existing XML file.' You can read an existing XML file into memory, add to the data model, and then write a new file. You can rename the old file and write the new file under the old name. But there is no commonly-used Java utility that will modify an XML file in place.

Upvotes: 6

GingerHead
GingerHead

Reputation: 8240

You need to use DOM to write/edit your xml file.
It's very easy:
You just need to create nodes and add attributes to it.
You can also write/edit XSLT files by using DOM.
just search google for DOM java

Upvotes: 1

Felix Christy
Felix Christy

Reputation: 2193

Please use xstream to parse your file as an object, or create a list with employees and then you can directly convert that to xml.

Upvotes: 2

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