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how to select nodes with different tags using DOM?

i have an xml file that looks like :
<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>
<HWData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<NE MOID="WBTS-42" NEType="WBTS">
<EQHO MOID="EQHO-1-0" >
<UNIT MOID="UNIT-FAN-1" State="enabled"></UNIT>
<UNIT MOID="UNIT-FAN-3" State="enabled"></UNIT>
</EQHO>
</NE>
<NE MOID="RNC-40" NEType="RNC">
<EQHO MOID="EQHO-3-0" >
<UNIT MOID="UNIT-FAN-5" State="disabled"></UNIT>
<UNIT MOID="UNIT-FAN-6" State="disabled"></UNIT>
</EQHO>
</NE>
</HWData>
i am asking for how can i get NodeList containing "NE" and "UNIT" tags using DOM ?
thanks

You can do it manually:
import java.io.File;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XmlDomTest {
public static void main(String[] args) throws Exception {
File file = new File("/path/to/your/file");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(file);
Set<String> filteredNames = new HashSet<String>(Arrays.asList("NE", "UNIT"));
NodeList list = collectNodes(doc, filteredNames);
for (int i = 0; i < list.getLength(); i++)
System.out.println(list.item(i).getNodeName());
}
private static NodeList collectNodes(Document doc, Set<String> filteredNames) {
Node ret = doc.createElement("NodeList");
collectNodes(doc, filteredNames, ret);
return ret.getChildNodes();
}
private static void collectNodes(Node node, Set<String> filteredNames, Node ret) {
NodeList chn = node.getChildNodes();
for (int i = 0; i < chn.getLength(); i++) {
Node child = chn.item(i);
if (filteredNames.contains(child.getNodeName()))
ret.appendChild(child);
collectNodes(child, filteredNames, ret);
}
}
}

try this :
public static List<String> MOIDList(File file) throws SAXException, IOException, ParserConfigurationException, XPathExpressionException{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(file);
XPath xPath = XPathFactory.newInstance().newXPath();
XPathExpression exp = xPath.compile("//NE | //UNIT");
NodeList nl = (NodeList)exp.evaluate(doc, XPathConstants.NODESET);
List<String> MoidList = new ArrayList<>();
for (int i = 0; i < nl.getLength(); i++) {
String moid=((Element)nl.item(i)).getAttribute("MOID");
MoidList.add(moid);
}
return MoidList;
}

The xpath to only select the MOIDS is //NE/#MOID | //UNIT/#MOID.
You should have a look at my open sourced Xml-parser-library unXml. It's available on Maven Central.
You can then do the following:
import com.nerdforge.unxml.Parsing;
import com.nerdforge.unxml.factory.ParsingFactory;
import org.w3c.dom.Document;
import java.util.List;
public class Parser {
public List<String> parseXml(String xml){
Parsing parsing = ParsingFactory.getInstance().create();
Document document = parsing.xml().document(xml);
List<String> result = parsing
.arr("//NE/#MOID | //UNIT/#MOID", parsing.text())
.as(String.class)
.apply(document);
return result;
}
}
parseXml will return the result:
[WBTS-42, UNIT-FAN-1, UNIT-FAN-3, RNC-40, UNIT-FAN-5, UNIT-FAN-6]
You can also create more complex nested datastructures if you need. Give me a comment here, if you want an example on how to do it.

Java Web Service & XML

I would need to build a simple program for my homework purposes that will retrieve data from an XML attribute based on the user input in a web service. To that end, I assumed I would start building a class that could parse my XML string and also I built a simple java service that does nothing but responds with a simple message. The problem is how do I put these together in order to get my program to work? Is this a good way to begin with? Please advise.
Also, to make thing a little more easier, the data in the string representation of XML has key words in both English and Serbian that would enable this web service to retrieve from one another:
import java.io.IOException;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class Recnik {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
String xmlString = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><!DOCTYPE language [<!ATTLIST phrase id ID #IMPLIED>]><language id=\"sr\"><phrase key=\"house\" value=\"kuca\"/><phrase key=\"dog\" value=\"pas\"/><phrase key=\"cat\" value=\"macka\"/></language>";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
//FileInputStream fis = new FileInputStream("myBooks.xml");
InputSource is = new InputSource(new StringReader(xmlString));
Document doc = db.parse(is);
Element r = doc.getDocumentElement();
NodeList language = r.getElementsByTagName("phrase");
System.out.println(language.item(1).getAttributes().item(0).getTextContent());
}
}
package Prevodilac;
import javax.jws.WebService;
import javax.jws.WebMethod;
import javax.jws.WebParam;
#WebService(serviceName = "Prevodilac")
public class Prevodilac {
#WebMethod(operationName = "pretraga")
public String pretraga(int a, int b) {
Integer res = a+b;
return res.toString();
}
}

#WebService(serviceName = "Prevodilac")
public class Prevodilac {
Document doc;
public Prevodilac() throws ParserConfigurationException, SAXException, IOException{
// Fill the document just once, not for each method call
String xmlString = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><!DOCTYPE language [<!ATTLIST phrase id ID #IMPLIED>]><language id=\"sr\"><phrase key=\"house\" value=\"kuca\"/><phrase key=\"dog\" value=\"pas\"/><phrase key=\"cat\" value=\"macka\"/></language>";
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource(new StringReader(xmlString));
doc = db.parse(is);
}
#WebMethod(operationName = "pretraga")
public String pretraga(String key) {
Element r = doc.getDocumentElement();
NodeList language = r.getElementsByTagName("phrase");
String result = "Not found";
for( int index = 0; index < language.getLength(); index++ ) {
Node attribute = language.item(index).getAttributes().getNamedItem("key");
// TODO (It's homework after all):
// check if the attribute corresponds to key parameter
if( attribute..... ){
// fill result with attribute value
result = ...;
}
}
return result;
}
}

Using JDOM to Parse XML file with external DTD that has not been declared in the XML file

In my XML file I have some entities such as ’
So I have created a DTD tag for my XML document to define these entities. Below is the Java code used to read the XML file.
SAXBuilder builder = new SAXBuilder();
URL url = new URL("http://127.0.0.1:8080/sample/subject.xml");
InputStream stream = url.openStream();
org.jdom.Document document = builder.build(stream);
Element root = document.getRootElement();
Element name = root.getChild("name");
result = name.getText();
System.err.println(result);
How can I change the Java code to retrieve a DTD over HTTP to allow the parsing of my XML document to be error free?
Simplified example of the xml document.
<main>
<name>hello ‘ world ’ foo & bar </name>
</main>

One way to do this would be to read the document and then validate it with the transformer:
import java.net.URL;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
public class ValidateWithExternalDTD {
private static final String URL = "http://127.0.0.1:8080/sample/subject.xml";
private static final String DTD = "http://127.0.0.1/YourDTD.dtd";
public static void main(String args[]) {
try {
DocumentBuilderFactory factory= DocumentBuilderFactory.newInstance();
factory.setValidating(true);
DocumentBuilder builder = factory.newDocumentBuilder();
// Set the error handler
builder.setErrorHandler(new org.xml.sax.ErrorHandler() {
public void fatalError(SAXParseException spex)
throws SAXException {
// output error and exit
spex.printStackTrace();
System.exit(0);
}
public void error(SAXParseException spex)
throws SAXParseException {
// output error and continue
spex.printStackTrace();
}
public void warning(SAXParseException spex)
throws SAXParseException {
// output warning and continue
spex.printStackTrace();
}
});
// Read the document
URL url = new URL(ValidateWithExternalDTD.URL);
Document xmlDocument = builder.parse(url.openStream());
DOMSource source = new DOMSource(xmlDocument);
// Use the tranformer to validate the document
StreamResult result = new StreamResult(System.out);
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, ValidateWithExternalDTD.DTD);
transformer.transform(source, result);
// Process your document if everything is OK
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
Another way would be to replace the XML title with the XML title plus the DTD reference
Replace this:
<?xml version = "1.0"?>
with this:
<?xml version = "1.0"?><!DOCTYPE ...>
Of course you would replace the first occurance only and not try to go through the whole xml document
You have to instantiate the SAXBuilder by passing true(validate) to its constructor:
SAXBuilder builder = new SAXBuilder(true);
or call:
builder.setValidation(true)

inserting xml:space='preserve' in the DOM

Java, Xerces 2.9.1
insertHere.setAttributeNS(XMLConstants.XML_NS_URI, "xml:space", "preserve");
and
insertHere.setAttributeNS(XMLConstants.XML_NS_URI, "space", "preserve")
both end up with an attribute of just space='preserve', no XML prefix.
insertHere.setAttribute( "xml:space", "preserve")
works, but it seems somehow wrong. Am I missing anything?
EDIT
I checked.
I read a template document in with setNamespaceAware turned on.
I then use the following to make a copy of it, and then I start inserting new elements.
public static Document copyDocument(Document input) {
DocumentType oldDocType = input.getDoctype();
DocumentType newDocType = null;
Document newDoc;
String oldNamespaceUri = input.getDocumentElement().getNamespaceURI();
if (oldDocType != null) {
// cloning doctypes is 'implementation dependent'
String oldDocTypeName = oldDocType.getName();
newDocType = input.getImplementation().createDocumentType(oldDocTypeName,
oldDocType.getPublicId(),
oldDocType.getSystemId());
newDoc = input.getImplementation().createDocument(oldNamespaceUri, oldDocTypeName,
newDocType);
} else {
newDoc = input.getImplementation().createDocument(oldNamespaceUri,
input.getDocumentElement().getNodeName(),
null);
}
Element newDocElement = (Element)newDoc.importNode(input.getDocumentElement(), true);
newDoc.replaceChild(newDocElement, newDoc.getDocumentElement());
return newDoc;
}

When I run the following code:
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
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 Demo {
public static void main(String[] args) throws Exception {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.newDocument();
Element rootElement = document.createElement("root");
document.appendChild(rootElement);
rootElement.setAttributeNS(XMLConstants.XML_NS_URI, "space", "preserve");
TransformerFactory tf = TransformerFactory.newInstance();
Transformer t = tf.newTransformer();
t.transform(new DOMSource(document), new StreamResult(System.out));
}
}
I get the following output:
<root xml:space="preserve"/>
How are you building your document?

Creating an XML document using namespaces in Java

I am looking for example Java code that can construct an XML document that uses namespaces. I cannot seem to find anything using my normal favourite tool so was hoping someone may be able to help me out.

There are a number of ways of doing this. Just a couple of examples:
Using XOM
import nu.xom.Document;
import nu.xom.Element;
public class XomTest {
public static void main(String[] args) {
XomTest xomTest = new XomTest();
xomTest.testXmlDocumentWithNamespaces();
}
private void testXmlDocumentWithNamespaces() {
Element root = new Element("my:example", "urn:example.namespace");
Document document = new Document(root);
Element element = new Element("element", "http://another.namespace");
root.appendChild(element);
System.out.print(document.toXML());
}
}
Using Java Implementation of W3C DOM
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
public class DomTest {
private static DocumentBuilderFactory dbf = DocumentBuilderFactory
.newInstance();
public static void main(String[] args) throws Exception {
DomTest domTest = new DomTest();
domTest.testXmlDocumentWithNamespaces();
}
public void testXmlDocumentWithNamespaces() throws Exception {
DocumentBuilder db = dbf.newDocumentBuilder();
DOMImplementation domImpl = db.getDOMImplementation();
Document document = buildExampleDocumentWithNamespaces(domImpl);
serialize(domImpl, document);
}
private Document buildExampleDocumentWithNamespaces(
DOMImplementation domImpl) {
Document document = domImpl.createDocument("urn:example.namespace",
"my:example", null);
Element element = document.createElementNS("http://another.namespace",
"element");
document.getDocumentElement().appendChild(element);
return document;
}
private void serialize(DOMImplementation domImpl, Document document) {
DOMImplementationLS ls = (DOMImplementationLS) domImpl;
LSSerializer lss = ls.createLSSerializer();
LSOutput lso = ls.createLSOutput();
lso.setByteStream(System.out);
lss.write(document, lso);
}
}

I am not sure, what you trying to do, but I use jdom for most of my xml-issues and it supports namespaces (of course).
The code:
Document doc = new Document();
Namespace sNS = Namespace.getNamespace("someNS", "someNamespace");
Element element = new Element("SomeElement", sNS);
element.setAttribute("someKey", "someValue", Namespace.getNamespace("someONS", "someOtherNamespace"));
Element element2 = new Element("SomeElement", Namespace.getNamespace("someNS", "someNamespace"));
element2.setAttribute("someKey", "someValue", sNS);
element.addContent(element2);
doc.addContent(element);
produces the following xml:
<?xml version="1.0" encoding="UTF-8"?>
<someNS:SomeElement xmlns:someNS="someNamespace" xmlns:someONS="someOtherNamespace" someONS:someKey="someValue">
<someNS:SomeElement someNS:someKey="someValue" />
</someNS:SomeElement>
Which should contain everything you need. Hope that helps.