Read Inner XML of a XML Element

Question

I was looking thru StackOverflow but i can't find best answer. I need to read XML file in JAVA. My XML file looks like below: `

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<server>
    <server01>
       <department>A1</department>
       <department>A2</department> 
    </server01>
    <server02>
       <department>A1</department>
       <department>A2</department> 
    </server02>
</server>

Is there a possiblity to read in Java elements between <server01> and <server02>, excluding rest of file? Or I need to use different tags? I found method how to read parentnodes:

NodeList serversNames = xmlD.getDocumentElement().getChildNodes();

for (int i = 0; i < serversNames.getLength(); i++) {
    Node node = serversNames.item(i);
    if (node instanceof Element) {
        Element childElement = (Element) node;
        System.out.println("tag name: " + childElement.getTagName());
    }
}

I am able to read all departments tags and save them to array:

NodeList serverName = xmlD.getElementsByTagName("department");

serversList = new String[serverName.getLength()];

System.out.println("zasieg: " + serverName.getLength());

for (int temp = 0; temp < serverName.getLength(); temp++) {
    Element shareName = null;

    shareName = (Element) serverName.item(temp);

    serversList[temp] = shareName.getTextContent();
    System.out.println(temp + " - " + serversList[temp]);
}

So, again, is there a possibility to read elements of parent node only? Elements of SERVER01 only?

Are you saying you want to stop reading the document after you have read the contents of and so not read in the contents of ? I think you need to define that logic in your program, it won't really be part of any XML parser. — Matt N, Sep 30 '13 at 18:31
It's not clear what you're trying to do or what the issue is. Can't you just use XPath or the equivalent? If you use an event-driven parser you can stop whenever you want, if it's really worth it. — Dave Newton, Sep 30 '13 at 18:32
you can use xstream to convert to XML to object and object to XML, Its very easy way to convert XML to object and object to XML. — cvsr.sarma, Sep 30 '13 at 18:42
Here is a useful reference: http://viralpatel.net/blogs/java-xml-xpath-tutorial-parse-xml/ — Rajesh, Sep 30 '13 at 18:43
@MattN: Not true. There are 2 methods of parsing XML markup: DOM (read the whole file into a tree data structure) and SAX (stream in the file and handle tags as they are encountered during parsing). Sounds like a SAX-based xml parsing approach with early termination would suit the OP's needs nicely. See http://stackoverflow.com/questions/6828703/difference-about-sax-and-dom — Asaph, Sep 30 '13 at 18:44

Nicolai · Accepted Answer · 2013-10-01T18:25:48.467

XPath is what you want. For all intents and purposes, you can think of xpath as you would sql, only it is for xml documents instead of databases. Here is a simple example using Java (keep in mind xpath is a standard and not specific to java, so you can find many ways of doing this in pretty much any popular language):

    // Load document
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse( new FileInputStream( "/tmp/xml" ) );

    // Create XPath expression
    XPathFactory xPathfactory = XPathFactory.newInstance();
    XPath xpath = xPathfactory.newXPath();
    XPathExpression expr = xpath.compile( "//server01" );

    // Find node 'server01'
    Node node = (Node) expr.evaluate( doc, XPathConstants.NODE );
    if( node == null ) {
        System.out.println( "Node not found" );
        System.exit( 0 );
    }

    // Extract departments
    Element server01 = (Element) node;
    for( int k = 0 ; k < server01.getChildNodes().getLength() ; k++ ) {
        Node childNode = server01.getChildNodes().item( k );
        // Check if current node is a department node
        if( "department".equals( childNode.getNodeName() ) ) {
            System.out.println( childNode.getNodeName() + ": " + childNode.getTextContent().trim() );
        }
    }

Is there is a possibility to avoid this?

Yes just change XPath expression an receive only nodes you need.

// Load document
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse( new FileInputStream( "/tmp/xml" ) );

// Create XPath expression
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile( "//server01/department" );

// Find nodes 'department' under node 'server01'
NodeList node = (NodeList) expr.evaluate( doc, XPathConstants.NODESET );

// Extract departments
for( int k = 0 ; k < node.getLength() ; k++ ) {
    Node childNode = node.item( k );
    // Check if current node is a department node
    if( "department".equals( childNode.getNodeName() ) ) {
        System.out.println( "[" + k + "] " + childNode.getNodeName() + ": " + childNode.getTextContent().trim() );
    }
}

You must receive the next output:

[0] department: A1
[1] department: A2

To ensure I'm not taking points from you as a result of my edits, I've deleted my answer and gave you an upvote since we basically had the same answer. — Dave, Sep 30 '13 at 18:59
Hi. This is a first simple solution. I am not surprised that I was not alone :) — Nicolai, Sep 30 '13 at 19:02
Thanks! It is very helpful :). But, there is one thing, that is don;t understand. The output from program is: `null 1 - AP null 3 - AR null 5 - GL null 7 - CS null 9 - CL ` Why it count in that way? Not 1,2,3... but only the odd numbers? — xeen, Oct 01 '13 at 18:05
Did you change original example? I've tested it and output shows correct lines: `department: A1` — Nicolai, Oct 01 '13 at 18:09
You receive 'department' node on odd iterations because there are '#text' node with '\n' content between tags. — Nicolai, Oct 01 '13 at 18:12
Awesome :) Great thing! I am not able to give you a reputation point. Many thanks for this! — xeen, Oct 01 '13 at 20:00

Read Inner XML of a XML Element

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