Develop Reference

DOM4J Parse not returning any child nodes

I am attempting to begin writing a program which uses DOM4j with which I wish to parse a XML file, save it to some tables and finally allow the user to manipulate the data.
Unfortunately I am stuck on the most basic step, the parsing.
Here is the portion of my XML I am attempting to include:
<?xml version="1.0"?>
<Document xmlns="urn:iso:std:iso:20022:tech:xsd:camt.054.001.04">
<BkToCstmrDbtCdtNtfctn>
<GrpHdr>
<MsgId>000022222</MsgId>
When I attempt to find the root of my XML it does return the root correctly as "Document". When I attempt to get the child node from Document it also correctly gives me "BkToCstmrDbtCdtNtfctn". The problem is that when I try to go any further and get the child nodes from "Bk" I can't. I get this in the console:
org.dom4j.tree.DefaultElement#2b05039f [Element: <BkToCstmrDbtCdtNtfctn uri: urn:iso:std:iso:20022:tech:xsd:camt.054.001.04 attributes: []/>]
Here is my code, I would appreciate any feedback. Ultimately I want to get the "MsgId" attribute back but in general I just want to figure how to parse deeper into the XML because in reality it probably has about 25 layers.
public static Document getDocument(final String xmlFileName){
Document document = null;
SAXReader reader = new SAXReader();
try{
document = reader.read(xmlFileName);
}
catch (DocumentException e)
{
e.printStackTrace();
}
return document;
}
public static void main(String args[]){
String xmlFileName = "C:\\Users\\jhamric\\Desktop\\Camt54.xml";
String xPath = "//Document";
Document document = getDocument(xmlFileName);
Element root = document.getRootElement();
List<Node> nodes = document.selectNodes(xPath);
for(Iterator i = root.elementIterator(); i.hasNext();){
Element element = (Element) i.next();
System.out.println(element);
}
for(Iterator i = root.elementIterator("BkToCstmrDbtCdtNtfctn");i.hasNext();){
Element bk = (Element) i.next();
System.out.println(bk);
}
}
}

The best approach is probably to use XPath, but since the XML document uses namespaces, you cannot use the "simple" selectNodes methods in the API. I would create a helper method to easily evaluate any XPath expression on either the Document or the Element level:
public static void main(String[] args) throws Exception {
Document doc = getDocument(...);
Map<String, String> namespaceContext = new HashMap<>();
namespaceContext.put("ns", "urn:iso:std:iso:20022:tech:xsd:camt.054.001.04");
// Select the first GrpHdr element in document order
Element element = (Element) select("//ns:GrpHdr[1]", doc, namespaceContext);
System.out.println(element.asXML());
// Select the text content of the MsgId element
Text msgId = (Text) select("./ns:MsgId/text()", element, namespaceContext);
System.out.println(msgId.getText());
}
static Object select(String expression, Branch contextNode, Map<String, String> namespaceContext) {
XPath xp = contextNode.createXPath(expression);
xp.setNamespaceURIs(namespaceContext);
return xp.evaluate(contextNode);
}
Note that the XPath expression must use namespace prefixes that is mapped to the namespace URIs used in the input document, but that the actual value of the prefix doesn't matter.

Convert XML String to ArrayList

Seems like a basic question but I can't find this anywhere. Basically I've got a list of XML links like so: (all in one string)
I already have the "string" var which contains all the XML. Just extracting the HTML strings.
<?xml version="1.0" encoding="UTF-8"?>
<fql_query_response xmlns="http://api.facebook.com/1.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" list="true">
<photo>
<src_small>http://photos-a.ak.fbcdn.net/hphotos-ak-ash4/486603_10151153207000351_1200565882_t.jpg</src_small>
</photo>
<photo>
<src_small>http://photos-c.ak.fbcdn.net/hphotos-ak-ash3/578919_10150988289678715_1110488833_t.jpg</src_small>
</photo>
I want to convert these into a arrayList, so something like URLArray[0] would be the first address as a string.
Can anyone tell me how to do this thanks?

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
InputSource is = new InputSource( new StringReader( xmlString) );
Document doc = builder.parse( is );
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
xpath.setNamespaceContext(new PersonalNamespaceContext());
XPathExpression expr = xpath.compile("//src_small/text()");
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
List<String> urls = new ArrayList<String>();
for (int i = 0; i < nodes.getLength(); i++) {
urls.add (nodes.item(i).getNodeValue());
System.out.println(nodes.item(i).getNodeValue());
}

You are right, there should be some other resources out there that can help you. Maybe your searches just do not use the right keywords.
You basically have 2 choices:
Use an XML processing library. SAX, DOM, XPATH, & xmlreader are some keywords you can use to find some.
Just ignore the fact that your string is xml and perform normal string operations on it. splits, iterate through it, regular expressions, ect...

Yes for that you have to perform XML Parsing.
then store that in ArrayList.
ex:
ArrayList<String> aList = new ArrayList<String>();
aList.add("your string");

Java XML Parse/Query

I have such XML structure, when I use NodeList nList = doc.getElementsByTagName("stock"); it return me 3 stocks, 2 main stock tags and one which is under substocks. I want to get only two stock which is on upper level and ignore all which is under substock tags.
Is it possible in Java to make something like LINQ query in C#, say return me elements only where name is equals to "Sony".
Thanks!
<city>
<stock>
<name>Sony</name>
</stock>
<stock>
<name>Panasonic</name>
<substocks>
<stock>
<name>Panasonic Shop 2</name>
</stock>
</substocks>
</stock>
</city>

I recommend you to use XPath with javax.xml.xpath package:
final InputStream is = new FileInputStream('your.xml');
final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
final DocumentBuilder builder = factory.newDocumentBuilder();
final Document doc = builder.parse(is);
final XPathFactory xPathfactory = XPathFactory.newInstance();
final XPath xpath = xPathfactory.newXPath();
final XPathExpression expr = xpath.compile("/city/stock/name[text()='Sony']");
and then:
final NodeList nl = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);

Take a look on XPath and its java implementation JXPath. Other possible approach is parsing XML using JAXB and operating objects list using LambdaJ.

There is also dom4j library which has powerful navigation with XPath:
import org.dom4j.Document;
import org.dom4j.io.SAXReader;
SAXReader reader = new SAXReader();
Document document = reader.read("test.xml");
List list = document.selectNodes("/city/stock/name[text()='Sony']");
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
// TODO: place you logic here
}
More examples are here

Try jcabi-xml (see this blog post) with a one-liner:
Collection<XML> found = new XMLDocument("your document here").nodes(
"/city/stock/name[text()='Sony']"
);

How to update XML using XPath and Java

I have an XML document, and an XPath expression for that doc. I have to update the doc by using XPath at runtime.
How can I do this using Java?
The below is my xml:
<?xml version="1.0" encoding="ISO-8859-1"?>
<PersonList>
<Person>
<Name>Sonu Kapoor</Name>
<Age>24</Age>
<Gender>M</Gender>
<PostalCode>54879</PostalCode>
</Person>
<Person>
<Name>Jasmin</Name>
<Age>28</Age>
<Gender>F</Gender>
<PostalCode>78745</PostalCode>
</Person>
<Person>
<Name>Josef</Name>
<Age>232</Age>
<Gender>F</Gender>
<PostalCode>53454</PostalCode>
</Person>
</PersonList>
I have to change the values of name and age under //PersonList/Person[2]/Name.

Use setNodeValue. First, get a NodeList, for example:
myNodeList = (NodeList) xpath.compile("//MyXPath/text()")
.evaluate(myXmlDoc, XPathConstants.NODESET);
Then set the value of e.g. the first node:
myNodeList.item(0).setNodeValue("Hi mom!");
More examples e.g. here.
As mentioned in two other answers here, as well as in your previous question: technically, XPath is not a way to "update" an XML document, but only to locate nodes within an XML document. But I presume the above is what you want.
EDIT: Responding to your comment... Are you asking how to write your DOM to an XML file after you've finished editing the DOM? If so, here are two examples of how to do it:
http://www.java2s.com/Code/Java/XML/WriteDOMout.htm
http://download.oracle.com/javaee/1.4/tutorial/doc/JAXPXSLT4.html

You can delete the file and create a new one.
Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(
new InputSource("data.xml"));
XPath xpath = XPathFactory.newInstance().newXPath();
NodeList nodes = (NodeList) xpath.evaluate("//employee/name[text()='old']", doc,
XPathConstants.NODESET);
for (int idx = 0; idx < nodes.getLength(); idx++) {
nodes.item(idx).setTextContent("new value");
}
Transformer xformer = TransformerFactory.newInstance().newTransformer();
xformer.transform(new DOMSource(doc), new StreamResult(new File("data_new.xml")));

XPath is used to select parts of an XML document.It has no provision for updating. But since it returns DOM objects (Elements, if memory serves, or maybe Nodes) you can then use DOM methods for altering the document.

XPath can be used to select nodes in a document, not for modification
You apply the xpath expression to your document and get an element (in your case). Once you have this Element, you can use the Element methods to change values (name and age in your case)
Starting from a NodeList it should work like that:
NodeList nodes = getNodeListFromXPathExpression(); // you know how
if (nodes.length == 0)
return; // empty nodelist, xpath didn't select anything
Node first = node.getItem(0); // take the first from the list, your element
// this is a shortcut for your example:
// first is the actual selected element (a node)
// .getFirst() returns the first child node, the "text node" (="Jasmine", ="28")
// .setNodeValue() replace the actual value of that text node with a new string
first.getFirstChild().setNodeValue("New Name or new age");

Consider using XQuery Update instead of XPath. This allows you to write
replace value of node //PersonList/Person[2]/Name with "Anonymous"
This is much easier than using the Java DOM API.

I've created a small project for using XPATH to create/update XML:
https://github.com/shenghai/xmodifier
the code to change your xml is like:
Document document = readDocument("personList.xml");
XModifier modifier = new XModifier(document);
modifier.addModify("//PersonList/Person[2]/Name", "newName");
modifier.modify();

This is a super cool function where you can able to modify any tag value for any XML document using its xpath. You need to pass three arguments xml,xpathExpression and newValue and it returns the XML file as String with modified value.
If you want to pass XML as file, you need to change the function accordingly. But the logic will be same.
public String updateXML(String xml, String xpathExpression, String newValue)
{
try {
//Creating document builder
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document document = builder.parse(new org.xml.sax.InputSource(new StringReader(xml)));
//Evaluating xpath expression using Element
XPath xpath = XPathFactory.newInstance().newXPath();
Element element = (Element)xpath.evaluate(xpathExpression, document, XPathConstants.NODE);
//Setting value in the text
element.setTextContent(value);
//Transformation of document to xml
StringWriter stringWriter = new StringWriter();
Transformer xformer = TransformerFactory.newInstance().newTransformer();
xformer.transform(new DOMSource(document), new StreamResult(stringWriter));
xml = stringWriter.toString();
}
catch (Exception e)
{
e.printStackTrace();
}
return xml;
}

Here is the code to change the content with vtd-xml... vtd-xml is unique in that it is the only API that offers incremental update capability.
import com.ximpleware.*;
import java.io.*;
public class changeName {
public static void main(String s[]) throws VTDException,java.io.UnsupportedEncodingException,java.io.IOException{
VTDGen vg = new VTDGen();
if (!vg.parseFile("input.xml", false))
return;
VTDNav vn = vg.getNav();
AutoPilot ap = new AutoPilot(vn);
XMLModifier xm = new XMLModifier(vn);
ap.selectXPath("//PersonList/Person[2]");
int i=0;
while((i=ap.evalXPath())!=-1){
if (vn.toElement(VTDNav.FIRST_CHILD,"Name")){
int k=vn.getText();
if (i!=-1)
xm.updateToken(k, "Jonathan");
vn.toElement(VTDNav.PARENT);
}
if (vn.toElement(VTDNav.FIRST_CHILD,"Age")){
int k=vn.getText();
if (i!=-1)
xm.updateToken(k, "42");
vn.toElement(VTDNav.PARENT);
}
}
xm.output("new.xml");
}
}

using xpath in java to go through this list?

i have an xml file that contains lots of different nodes. some in particularly are nested like this:
<emailAddresses>
<emailAddress>
<value>sambj1981#gmail.com</value>
<typeSource>WORK</typeSource>
<typeUser></typeUser>
<primary>false</primary>
</emailAddress>
<emailAddress>
<value>sambj#hotmail.co.uk</value>
<typeSource>HOME</typeSource>
<typeUser></typeUser>
<primary>true</primary>
</emailAddress>
</emailAddresses>
From the above node, what i want to do is go through each and get the values inside it(value, typeSource, typeUser etc) and put them in a POJO.
i tried to see if i can use this xpath expression "//emailAddress" but it doesnt return me the tags inside inside it. maybe i am doing it wrong. i am pretty new to using xpath.
i could do something like this:
//emailAddress/value | //emailAddress/typeSource | .. but doing that will list all elements values together if im not mistaken leaving me to work out when i have finished reading from a specific emailAddress tag and going to the next emailAddress tag.
well to sum up my needs i basically want this to be returned similar to how you would return results from a bog standard sql query that returns results in a row. i.e. if your sql query produces 10 emailAddress, it will return each emailAddress in a row and i can simply iterate over "each emailAddress" and get the appropriate value based on the colunm name or index.

No,
//emailAddress
doesn't return the tags inside, that is correct. What it does return is a NodeList/NodeSet. To actually get the values you can do something like this:
String emailpath = "//emailAddress";
String emailvalue = ".//value";
XPathFactory xPathFactory = XPathFactory.newInstance();
XPath xpath = xPathFactory.newXPath();
Document document;
public XpathStuff(String file) throws ParserConfigurationException, IOException, SAXException {
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = docFactory.newDocumentBuilder();
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
document = builder.parse(bis);
NodeList nodeList = getNodeList(document, emailpath);
for(int i = 0; i < nodeList.getLength(); i++){
System.out.println(getValue(nodeList.item(i), emailvalue));
}
bis.close();
}
public NodeList getNodeList(Document doc, String expr) {
try {
XPathExpression pathExpr = xpath.compile(expr);
return (NodeList) pathExpr.evaluate(doc, XPathConstants.NODESET);
} catch (XPathExpressionException e) {
e.printStackTrace();
}
return null;
}
//extracts the String value for the given expression
private String getValue(Node n, String expr) {
try {
XPathExpression pathExpr = xpath.compile(expr);
return (String) pathExpr.evaluate(n,
XPathConstants.STRING);
} catch (XPathExpressionException e) {
e.printStackTrace();
}
return null;
}
Maybe I should point out that when iterating over the Nodelist, in .//values the first dot means the current context. Without the dot you would get the first node all the time.

//emailAddress/*
will get these nodes in the document order.
It depends on how you want to iterate through the nodes. We do all our XML using XOM (http://www.xom.nu/) which is an easy reliable Java package. It's possible to write your own strategy using XOM calls.

If you use XStream you can set it up quite easily. Like so:
#XStreamAlias( "EmailAddress" )
public class EmailAddress {
#XStreamAlias()
private String value;
#XStreamAlias()
private String typeSource;
#XStreamAlias()
private String typeUser;
#XStreamAlias()
private boolean primary;
// ... the rest omitted for brevity
}
You then marshal & unmarshal quite simply like so:
XStream xstream = new XStream();
xstream.processAnnotations( EmailAddress.class );
xstream.toXML( /* Object value here */ emailAddress );
xstream.fromXML( /* String xml value here */ "" );
IDK if you have to use XPath or not, but if not I'd consider an out of the box solution like this.

I am totally aware this is not what you were asking for, but may consider using jibx. This is a tool for human-readable XML to POJO mapping.
So I believe you could generate mapping for your email structure in a quick way and let the jibx do the work for you.