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How to read < as < from an XML? [duplicate]

I am new to XML. I want to read the following XML on the basis of request name. Please help me on how to read the below XML in Java -
<?xml version="1.0"?>
<config>
<Request name="ValidateEmailRequest">
<requestqueue>emailrequest</requestqueue>
<responsequeue>emailresponse</responsequeue>
</Request>
<Request name="CleanEmail">
<requestqueue>Cleanrequest</requestqueue>
<responsequeue>Cleanresponse</responsequeue>
</Request>
</config>

If your XML is a String, Then you can do the following:
String xml = ""; //Populated XML String....
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new InputSource(new StringReader(xml)));
Element rootElement = document.getDocumentElement();
If your XML is in a file, then Document document will be instantiated like this:
Document document = builder.parse(new File("file.xml"));
The document.getDocumentElement() returns you the node that is the document element of the document (in your case <config>).
Once you have a rootElement, you can access the element's attribute (by calling rootElement.getAttribute() method), etc. For more methods on java's org.w3c.dom.Element
More info on java DocumentBuilder & DocumentBuilderFactory. Bear in mind, the example provided creates a XML DOM tree so if you have a huge XML data, the tree can be huge.
Related question.
Update Here's an example to get "value" of element <requestqueue>
protected String getString(String tagName, Element element) {
NodeList list = element.getElementsByTagName(tagName);
if (list != null && list.getLength() > 0) {
NodeList subList = list.item(0).getChildNodes();
if (subList != null && subList.getLength() > 0) {
return subList.item(0).getNodeValue();
}
}
return null;
}
You can effectively call it as,
String requestQueueName = getString("requestqueue", element);

In case you just need one (first) value to retrieve from xml:
public static String getTagValue(String xml, String tagName){
return xml.split("<"+tagName+">")[1].split("</"+tagName+">")[0];
}
In case you want to parse whole xml document use JSoup:
Document doc = Jsoup.parse(xml, "", Parser.xmlParser());
for (Element e : doc.select("Request")) {
System.out.println(e);
}

If you are just looking to get a single value from the XML you may want to use Java's XPath library. For an example see my answer to a previous question:
How to use XPath on xml docs having default namespace
It would look something like:
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
public class Demo {
public static void main(String[] args) {
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document dDoc = builder.parse("E:/test.xml");
XPath xPath = XPathFactory.newInstance().newXPath();
Node node = (Node) xPath.evaluate("/Request/#name", dDoc, XPathConstants.NODE);
System.out.println(node.getNodeValue());
} catch (Exception e) {
e.printStackTrace();
}
}
}

There are a number of different ways to do this. You might want to check out XStream or JAXB. There are tutorials and the examples.

If the XML is well formed then you can convert it to Document. By using the XPath you can get the XML Elements.
String xml = "<stackusers><name>Yash</name><age>30</age></stackusers>";
Form XML-String Create Document and find the elements using its XML-Path.
Document doc = getDocument(xml, true);
public static Document getDocument(String xmlData, boolean isXMLData) throws Exception {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
dbFactory.setNamespaceAware(true);
dbFactory.setIgnoringComments(true);
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc;
if (isXMLData) {
InputSource ips = new org.xml.sax.InputSource(new StringReader(xmlData));
doc = dBuilder.parse(ips);
} else {
doc = dBuilder.parse( new File(xmlData) );
}
return doc;
}
Use org.apache.xpath.XPathAPI to get Node or NodeList.
System.out.println("XPathAPI:"+getNodeValue(doc, "/stackusers/age/text()"));
NodeList nodeList = getNodeList(doc, "/stackusers");
System.out.println("XPathAPI NodeList:"+ getXmlContentAsString(nodeList));
System.out.println("XPathAPI NodeList:"+ getXmlContentAsString(nodeList.item(0)));
public static String getNodeValue(Document doc, String xpathExpression) throws Exception {
Node node = org.apache.xpath.XPathAPI.selectSingleNode(doc, xpathExpression);
String nodeValue = node.getNodeValue();
return nodeValue;
}
public static NodeList getNodeList(Document doc, String xpathExpression) throws Exception {
NodeList result = org.apache.xpath.XPathAPI.selectNodeList(doc, xpathExpression);
return result;
}
Using javax.xml.xpath.XPathFactory
System.out.println("javax.xml.xpath.XPathFactory:"+getXPathFactoryValue(doc, "/stackusers/age"));
static XPath xpath = javax.xml.xpath.XPathFactory.newInstance().newXPath();
public static String getXPathFactoryValue(Document doc, String xpathExpression) throws XPathExpressionException, TransformerException, IOException {
Node node = (Node) xpath.evaluate(xpathExpression, doc, XPathConstants.NODE);
String nodeStr = getXmlContentAsString(node);
return nodeStr;
}
Using Document Element.
System.out.println("DocumentElementText:"+getDocumentElementText(doc, "age"));
public static String getDocumentElementText(Document doc, String elementName) {
return doc.getElementsByTagName(elementName).item(0).getTextContent();
}
Get value in between two strings.
String nodeVlaue = org.apache.commons.lang.StringUtils.substringBetween(xml, "<age>", "</age>");
System.out.println("StringUtils.substringBetween():"+nodeVlaue);
Full Example:
public static void main(String[] args) throws Exception {
String xml = "<stackusers><name>Yash</name><age>30</age></stackusers>";
Document doc = getDocument(xml, true);
String nodeVlaue = org.apache.commons.lang.StringUtils.substringBetween(xml, "<age>", "</age>");
System.out.println("StringUtils.substringBetween():"+nodeVlaue);
System.out.println("DocumentElementText:"+getDocumentElementText(doc, "age"));
System.out.println("javax.xml.xpath.XPathFactory:"+getXPathFactoryValue(doc, "/stackusers/age"));
System.out.println("XPathAPI:"+getNodeValue(doc, "/stackusers/age/text()"));
NodeList nodeList = getNodeList(doc, "/stackusers");
System.out.println("XPathAPI NodeList:"+ getXmlContentAsString(nodeList));
System.out.println("XPathAPI NodeList:"+ getXmlContentAsString(nodeList.item(0)));
}
public static String getXmlContentAsString(Node node) throws TransformerException, IOException {
StringBuilder stringBuilder = new StringBuilder();
NodeList childNodes = node.getChildNodes();
int length = childNodes.getLength();
for (int i = 0; i < length; i++) {
stringBuilder.append( toString(childNodes.item(i), true) );
}
return stringBuilder.toString();
}
OutPut:
StringUtils.substringBetween():30
DocumentElementText:30
javax.xml.xpath.XPathFactory:30
XPathAPI:30
XPathAPI NodeList:<stackusers>
<name>Yash</name>
<age>30</age>
</stackusers>
XPathAPI NodeList:<name>Yash</name><age>30</age>

following links might help
http://labe.felk.cvut.cz/~xfaigl/mep/xml/java-xml.htm
http://developerlife.com/tutorials/?p=25
http://www.java-samples.com/showtutorial.php?tutorialid=152

There are two general ways of doing that. You will either create a Domain Object Model of that XML file, take a look at this
and the second choice is using event driven parsing, which is an alternative to DOM xml representation. Imho you can find the best overall comparison of these two basic techniques here. Of course there are much more to know about processing xml, for instance if you are given XML schema definition (XSD), you could use JAXB.

There are various APIs available to read/write XML files through Java.
I would refer using StaX
Also This can be useful - Java XML APIs

You can make a class which extends org.xml.sax.helpers.DefaultHandler and call
start_<tag_name>(Attributes attrs);
and
end_<tag_name>();
For it is:
start_request_queue(attrs);
etc.
And then extends that class and implement xml configuration file parsers you want. Example:
...
public void startElement(String uri, String name, String qname,
org.xml.sax.Attributes attrs)
throws org.xml.sax.SAXException {
Class[] args = new Class[2];
args[0] = uri.getClass();
args[1] = org.xml.sax.Attributes.class;
try {
String mname = name.replace("-", "");
java.lang.reflect.Method m =
getClass().getDeclaredMethod("start" + mname, args);
m.invoke(this, new Object[] { uri, (org.xml.sax.Attributes)attrs });
}
catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
catch (NoSuchMethodException e) {
throw new RuntimeException(e); }
catch (java.lang.reflect.InvocationTargetException e) {
org.xml.sax.SAXException se =
new org.xml.sax.SAXException(e.getTargetException());
se.setStackTrace(e.getTargetException().getStackTrace());
}
and in a particular configuration parser:
public void start_Request(String uri, org.xml.sax.Attributes attrs) {
// make sure to read attributes correctly
System.err.println("Request, name="+ attrs.getValue(0);
}

Since you are using this for configuration, your best bet is apache commons-configuration. For simple files it's way easier to use than "raw" XML parsers.
See the XML how-to

How to stop XML Tag Attributes from sorting in Ascending Order after modifying the XML file using Java?

I have written a program to find all XML files matching a particular pattern in a directory and modify it by adding a new tag.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<paths>
<upgradepath startversion="1.4.0.0" moduleid="${moduleId}" endversion="1.4.0.1">
<steps>
<!-- Put scripts here to go from 1.4.0.0 to 1.4.0.1 -->
</steps>
</upgradepath>
<upgradepath startversion="1.4.0.1" moduleid="${moduleId}" endversion="1.4.0.2">
<steps>
<!-- Put scripts here to go from 1.4.0.1 to 1.4.0.2 -->
</steps>
</upgradepath>
</paths>
After running my program the XML file gets modified as below :
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<paths>
<upgradepath endversion="1.4.0.1" moduleid="${moduleId}" startversion="1.4.0.0">
<steps>
<!-- Put scripts here to go from 1.4.0.0 to 1.4.0.1 -->
</steps>
</upgradepath>
<upgradepath endversion="1.4.0.2" moduleid="${moduleId}" startversion="1.4.0.1">
<steps>
<!-- Put scripts here to go from 1.4.0.1 to 1.4.0.2 -->
</steps>
</upgradepath>
<upgradepath endversion="1.4.0.3" moduleid="${moduleId}" startversion="1.4.0.2">
<steps>
<!--Put scripts here to go from 1.4.0.2 to 1.4.0.3-->
</steps>
</upgradepath>
</paths>
If you see the attributes of all the tags you will see that they have all been rearranged in ascending order. The startversion attribute now appears last and the endversion attribute appears first. I want the original order of the attributes after modification of the XML file. I have tried almost everything and have lost all hope. Is there any way I can do this? Also is there a way to sort the attributes in descending order? It's not the right solution but it helps.
Here is a code snippet from the program I am using to modify the files :
private static void updateXMLFiles(String sStartVersion, String sEndVersion) {
try {
for (int c = 0; c < pathsList.size(); c++) {
File xmlFile = new File(pathsList.get(c).toString());
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder;
dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(xmlFile);
doc.getDocumentElement().normalize();
// Get the last <upgradepath> tag in the file.
// Method Call to verify the version entered and update the XML Files.
// Write the updated document to the file.
doc.getDocumentElement().normalize();
TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(pathsList.get(c).toString()));
transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
transformer.transform(source, result);
}
catch (SAXException e1) {
e1.printStackTrace();
}
catch (ParserConfigurationException e1) {
e1.printStackTrace();
}
catch (IOException e1) {
e1.printStackTrace();
}
catch (TransformerException e1) {
e1.printStackTrace();
}
}
private static void addNewVersion(Document doc, String sStartVersion, String sEndVersion) {
Element element = doc.getDocumentElement();
Element upgradePath = doc.createElement("upgradepath");
upgradePath.setAttribute("startversion", sStartVersion);
upgradePath.setAttribute("moduleid", "${moduleId}");
upgradePath.setAttribute("endversion", sEndVersion);
Element steps = doc.createElement("steps");
Comment comment = doc.createComment("Put scripts here to go from " + sStartVersion + " to " + sEndVersion);
steps.appendChild(comment);
upgradePath.appendChild(steps);
element.appendChild(upgradePath);
}
Is there any way I can keep the order of the attributes intact or in the worst case arrange it in descending order?
A friend of mine suggested I try out JAXB but I couldn't find a way to achieve this. If someone thinks JAXB can solve this do mention how to format an existing XML file and not creating one.
Another issue which is not a major concern is that although I have used the
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
the newly added tags are not indented correctly. Any way to fix this?

#XmlType(propOrder = {"startversion", "moduleid", "endversion", "steps"})
public class XmlSubModel {
private String startversion = "";
private String moduleid = "";
private String endversion = "";
private String steps = "";
#XmlAttribute
public String getStartversion() {
return startversion;
}
public void setStartversion(String startversion) {
this.startversion = startversion;
}
#XmlAttribute
public String getModuleid() {
return moduleid;
}
public void setModuleid(String moduleid) {
this.moduleid = moduleid;
}
#XmlAttribute
public String getEndversion() {
return endversion;
}
public void setEndversion(String endversion) {
this.endversion = endversion;
}
public String getSteps() {
return steps;
}
public void setSteps(String steps) {
this.steps = steps;
}
}

JAK generated KML not work with Google My Maps

I write manually a KML file trying to import some polygons in MyMaps. This way works fine:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0">
<Document>
<Placemark>
<Style>
<PolyStyle>
<color>#a00000ff</color>
<outline>0</outline>
</PolyStyle>
</Style>
<Polygon>
<outerBoundaryIs>
<LinearRing>
<coordinates>9.184254,45.443636 9.183379,45.434288 9.224836,45.431499 9.184254,45.443636</coordinates>
</LinearRing>
</outerBoundaryIs>
</Polygon>
</Placemark>
</Document>
</kml>
I try to write a java program using JAK that generate a most possibile equal file, but it doesn't work with Maps
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns3:kml xmlns:atom="http://www.w3.org/2005/Atom" xmlns:ns3="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:xal="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0">
<ns3:Document>
<ns3:Placemark>
<ns3:Style>
<ns3:PolyStyle>
<ns3:color>#EABCFF</ns3:color>
<ns3:outline>0</ns3:outline>
</ns3:PolyStyle>
</ns3:Style>
<ns3:Polygon>
<ns3:innerBoundaryIs>
<ns3:LinearRing>
<ns3:coordinates>9.184254,45.443636 9.183379,45.434288 9.224836,45.431499 9.184254,45.443636</ns3:coordinates>
</ns3:LinearRing>
</ns3:innerBoundaryIs>
</ns3:Polygon>
</ns3:Placemark>
</ns3:Document>
</ns3:kml>
That's program:
public static void main(String[] args) throws IOException {
// Style
PolyStyle polystyle = KmlFactory.createPolyStyle();
polystyle.setColor("#EABCFF");
// polystyle.setFill(true);
polystyle.setOutline(false);
//
Kml kml = KmlFactory.createKml();
Document document = kml.createAndSetDocument();
Placemark pm = document.createAndAddPlacemark();
LinearRing linearRing = pm.createAndSetPolygon().createAndAddInnerBoundaryIs().createAndSetLinearRing();
linearRing.addToCoordinates(9.184254, 45.443636, 0);
linearRing.addToCoordinates(9.183379, 45.434288, 0);
linearRing.addToCoordinates(9.224836, 45.431499, 0);
linearRing.addToCoordinates(9.184254, 45.443636, 0);
pm.createAndAddStyle().setPolyStyle(polystyle);
//
kml.marshal(new FileWriter("D:/prova.kml"));
}

I view <ns3: in your kml this make the kml invalid for google maps
Try to correct the file

I had the same problem.
Instead of using kml.marshal(new FileWriter("D:/prova.kml")); I did this...
String name = kml.getClass().getSimpleName();
if ("Kml".equals(name)) {
name = name.toLowerCase();
}
JAXBContext jaxbContext = JAXBContext.newInstance(Kml.class);
Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
// output pretty printed
jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
jaxbMarshaller.setProperty("com.sun.xml.bind.namespacePrefixMapper", new NameSpaceBeautyfier());
JAXBElement<Kml> jaxbKml = new JAXBElement<>(new QName("http://www.opengis.net/kml/2.2", name), (Class<Kml>) kml.getClass(), kml);
jaxbMarshaller.marshal(jaxbKml, file);
With a NameSpaceBeautifier like this ...
private static final class NameSpaceBeautyfier extends NamespacePrefixMapper {
private static final String KML_PREFIX = ""; // DEFAULT NAMESPACE
private static final String KML_URI= "http://www.opengis.net/kml/2.2";
#Override
public String getPreferredPrefix(String namespaceUri, String suggestion, boolean requirePrefix) {
if(KML_URI.equals(namespaceUri)) {
return KML_PREFIX;
}
return suggestion;
}
#Override
public String[] getPreDeclaredNamespaceUris() {
return new String[] { KML_URI };
}
private NameSpaceBeautyfier() {
}
}
Hope this helps..

Cannot return an org.w3c.dom.Document by web-service method

I am trying to return an XML Document Object from a java axis2 web service. When I am trying to get the Document object on the client side, it gives me these exceptions.
org.apache.axis2.AxisFault: org.apache.axis2.AxisFault: Mapping qname not fond for the package: com.sun.org.apache.xerces.internal.dom
at org.apache.axis2.util.Utils.getInboundFaultFromMessageContext(Utils.java:531)
at org.apache.axis2.description.OutInAxisOperationClient.handleResponse(OutInAxisOperation.java:375)
at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:421)
at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:229)
at org.apache.axis2.client.OperationClient.execute(OperationClient.java:165)
at com.turnkey.DataCollectorStub.getData(DataCollectorStub.java:194)
at com.turnkey.TestClient.main(TestClient.java:28)
Can I not return the Document object from a webservice ??
This service does return the XML string though.
Below is the pseudo code for the method I am using
import java.io.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
public Document getData(args)
{
String xmlSource = "/*XML string*/";
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document xmlDoc = builder.parse(new InputSource(new StringReader(xmlSource)));
return xmlDoc;
}
BTW, this method works fine on the server side, But on the client side I cannot receive the Document object
Can anybody please help me.

Simple way doesn't use Document as return value, because axis2 cannot find suitable import in schema. If you generate wsdl every time you should add import org.w3c.dom.Document to wsdl schema (it is a inconvenient solution). That's why the best way in my point of view return specific entity
public Credit[] getCreditList(){
Credit[] credits = null;
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = factory.newDocumentBuilder();
Document xmlDoc = documentBuilder.parse(XML_REAL_PATH);
Element root = xmlDoc.getDocumentElement();
List<Credit> creditsList = new ArrayList<>();
NodeList creditNodes = root.getElementsByTagName(CREDIT);
int countCreditNodes = creditNodes.getLength();
for (int i = 0; i < countCreditNodes; i++) {
Element creditElement = (Element) creditNodes.item(i);
Credit credit = new Credit();
Element child = (Element) creditElement.getElementsByTagName(OWNER).item(0);
String owner = child.getFirstChild().getNodeValue();
credit.setOwner(owner);
//...
creditsList.add(credit);
}
credits = creditsList.toArray(new Credit[creditsList.size()]);
} catch (SAXException | IOException | ParserConfigurationException ex) {
Logger.getLogger(CreditPayService.class.getName()).log(Level.SEVERE, null, ex);
}
return credits;
}

SAXException when parsing XML file with XSD schema

I have the following XSD file:
<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'
targetNamespace='http://www.wvf.com/schemas'
xmlns='http://www.wvf.com/schemas'
xmlns:acmewvf='http://www.wvf.com/schemas'>
<xs:element name='loft'>
</xs:element>
</xs:schema>
and the following XML file:
<?xml version="1.0"?>
<acmewvf:loft xmlns:acmewvf="http://www.wvf.com/schemas"
xmlns="http://www.wvf.com/schemas">
</acmewvf:loft>
When I execute the following Java code:
public void parse(InputStream constraints) {
final SchemaFactory schemaFactory = new XMLSchemaFactory();
final URL resource =
ClassLoader.getSystemClassLoader().getResource(SCHEMA_PATH);
final DocumentBuilderFactory factory =
DocumentBuilderFactory.newInstance();
Document doc = null;
factory.setSchema(schemaFactory.newSchema(resource));
final DocumentBuilder builder = factory.newDocumentBuilder();
doc = builder.parse(constraints);
I get the following SAXException (on the last line of the code):
cvc-elt.1: Cannot find the declaration
of element 'acmewvf:loft'.
(Note that SCHEMA_PATH points to the XSD file whose contents are given above and constraints is an input stream to the XML file whose contents are also given above.)
What's going wrong here?

See Using the Validating Parser. Probably, you should try to add the following to generate a namespace-aware, validating parser:
factory.setNamespaceAware(true);
factory.setValidating(true);
try {
factory.setAttribute(JAXP_SCHEMA_LANGUAGE, W3C_XML_SCHEMA);
}
catch (IllegalArgumentException x) {
// Happens if the parser does not support JAXP 1.2
...
}
Don't forget to define:
static final String JAXP_SCHEMA_LANGUAGE =
"http://java.sun.com/xml/jaxp/properties/schemaLanguage";
static final String W3C_XML_SCHEMA =
"http://www.w3.org/2001/XMLSchema";