We Keep Coding

Java XPath scan file looking for a word

Im building an application that will taka a word from user and then scan file using XPath returning true or false depending on wheather the word was found in that file or not.
I have build following class that implements XPath, but i am either missunderstanding how it should work or there is something wrong with my code. Can anyone explain to me how to use Xpath to make full file search?
public XPath() throws IOException, SAXException, ParserConfigurationException, XPathExpressionException {
FileInputStream fileIS = new FileInputStream("text.xml");
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document xmlDocument = builder.parse(fileIS);
XPathFactory xPathfactory = XPathFactory.newInstance();
javax.xml.xpath.XPath xPath = xPathfactory.newXPath();
XPathExpression expr = xPath.compile("//text()[contains(.,'java')]");
System.out.println(expr.evaluate(xmlDocument, XPathConstants.NODESET));
}
And the xml file i am currently testing on.
<?xml version="1.0"?>
<Tutorials>
<Tutorial tutId="01" type="java">
<title>Guava</title>
<description>Introduction to Guava</description>
<date>04/04/2016</date>
<author>GuavaAuthor</author>
</Tutorial>
<Tutorial tutId="02" type="java">
<title>XML</title>
<description>Introduction to XPath</description>
<date>04/05/2016</date>
<author>XMLAuthor</author>
</Tutorial>
</Tutorials>
Found the solution, i was missing correct display of the found entries and as someone pointed out in comment 'java' is in arguments and i want to scan only text fields so it would be never found, after adding following code and changing the word my app will look for, application works
Object result = expr.evaluate(xmlDocument, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}

Your XPath is searching the text() nodes, but the word java appears in the #type attribute (which is not a text() node).
If you want to search for the word in both text() and #* then you could use a union | operator and check for either/both containing that word:
//text()[contains(. ,'java')] | //#*[contains(., 'java')]
But you might also want to scan comment() and processing-instruction(), so could generically match on node() and then in the predicate test:
//node()[contains(. ,'java')] | //#*[contains(., 'java')]
With XPath 2.0 or greater, you could use:
//node()[(.|#*)[contains(., 'java')]]

How to extract data from <dc> tag in java?

I am currently trying to extract the tag element < dc:title > from an epub in Java. However, i tried using
doc.getDocumentElement().getElementsByTagName("dc:title"));
and it only showed 2nd element :com.sun.org.apache.xerces.internal.dom.DeepNodeListImpl. I would like to know how can I extract < dc:tittle > ?
Here is my code:
File fXmlFile = new File("file directory");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
doc.getDocumentElement().normalize();
System.out.println("1st element :" + doc.getElementsByTagName("dc");
System.out.println("2nd element :" + doc.getDocumentElement().getElementsByTagName("dc:title"));
System output:
1st element : com.sun.org.apache.xerces.internal.dom.DeepNodeListImpl#4f53e9be
2nd element :com.sun.org.apache.xerces.internal.dom.DeepNodeListImpl#e16e1a2
Added Sample Data
<dc:title>
<![CDATA[someData]]>
</dc:title>
<dc:creator>
<![CDATA[someData]>
</dc:creator>
<dc:language>someData</dc:language>

The method getElementsByTagName(String) is return a List of matching elements (note plural 's'). You then need to specify which element (such as by using .item(index) to access a Node instance) you want to use. Therewith, you can using getNodeValue() on that Node object.
EDITED: because of the CDATA element, rather use Node.getTextContent():
NodeList elems = doc.getElementsByTagName("dc:title");
Node item = elems.item(0);
System.out.println(item.getTextContent());

I would suggest using xpath to get the desired output.
Also, refer following link for examples.
https://www.journaldev.com/1194/java-xpath-example-tutorial
For example:
XPath xPath = XPathFactory.newInstance().newXPath();
String expression = "//dc:title/text()";
NodeList nodes = (NodeList) xPath.compile(expression).evaluate(doc, XPathConstants.NODESET);
System.out.println(nodes.item(0).getNodeValue());

Java - Handle XML With Less Than/Greater Than Symbols in Text

I am trying to parse an XML file with the "less than" and "greater than" symbols in the text.
Here is a sample XML file:
<document>
<summary>
The equation for t is: 567<T<600.
</summary>
</document>
Is there any way to handle this in a Java XML parser? I know about escaping and changing to
<
and
>
but I only want to escape the characters in the text.
Currently, I am trying to use the DocumentBuilder, but it is erroring out.
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
domFactory.setExpandEntityReferences(false);
try {
DocumentBuilder builder = domFactory.newDocumentBuilder();
Document document = builder.parse(new InputSource(new StringReader(sectionXML.toString())));
} catch (ParserConfigurationException e) {
e.printStackTrace();
}
The error I am getting is:
[Fatal Error] :1:70: Element type "T" must be followed by either attribute specifications, ">" or "/>".
org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 70; Element type "T" must be followed by either attribute specifications, ">" or "/>".
Any thoughts? Thanks in advance for any help.

add two namespaces into same dom element

I need create a dom document as this:
<namespace:Facturae xmlns:namespace="URI1" xmlns:namespace2="URI2">
//<.......
</namespace:Facturae>
But the following code produce the error:
NAMESPACE_ERR: An attempt is made to create or change an object in a way which is incorrect with regard to namespaces.
The code is:
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.newDocument();
Element FacturaeElement = document.createElementNS("URI1", "Facturae");
document.appendChild(FacturaeElement);
FacturaeElement.setPrefix("namespace"); //First namespace OK
FacturaeElement.setAttributeNS("URI2", "xmlns:namespace2", "aaa"); //Generate error
//Rest of code
How I can put a second namespace into element??

Searching more information I have reached the solution:
I use the normal setAtribute method (without namespace) indicating the name of the atribute with the xmlns prefix so: "xmlns:namespace2".
Then, I create the sub element with this the namespace and later put the prefix.
Element FacturaeElement = document.createElementNS("URI1", "Facturae");
document.appendChild(FacturaeElement);
FacturaeElement.setPrefix("namespace"); //First namecpace
FacturaeElement.setAttribute("xmlns:namespace2", "URI2"); //second namespace
//I create the subelement with a namespace
Element FileHeaderElement = document.createElementNS("URI2", "FileHeader");
FacturaeElement.appendChild(FileHeaderElement);
FileHeaderElement.setPrefix("namespace2");

Getting the value of an attribute in Java from a XML using XPath

I'm currently using XPath to get some information from a podcast feed using Java and XPath. I'm trying to read the attribute of a node:
<?xml version="1.0" encoding="UTF-8"?>
<rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:admin="http://webns.net/mvcb/" xmlns:atom="http://www.w3.org/2005/Atom/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" version="2.0">
<channel>
[....]
<itunes:image href="http://icebox.5by5.tv/images/broadcasts/14/cover.jpg" />
[...]
I want to get the value of the href attribute in <itunes:image>. Currently, I'm using the following code:
private static String IMAGE_XPATH = "//channel/itunes:image/#href";
String imageUrl = xpath.compile(IMAGE_XPATH).evaluate(doc, XPathConstants.STRING).toString();
The result of imageUrl is null. What happens in the code? Do I have an error in the XPath code, or in the Java code?
Thanks! :)

Disable namespace awarness:
DocumentBuilderFactory xmlFact = DocumentBuilderFactory.newInstance();
xmlFact.setNamespaceAware(false);
Your xpath expression should look like this now:
"//channel/image/#href"
If you need to use it as namespace aware, just implement your own NameSpaceContext, should look like this:
NamespaceContext ctx = new ItunesNamespaceContext();
XPathFactory xpathFact = XPathFactory.newInstance();
XPath xpath = xpathFact.newXPath();
xpath.setNamespaceContext(ctx);
String IMAGE_XPATH = "//channel/itunes:image/#href";
String imageUrl = path.compile(IMAGE_XPATH).evaluate(doc,XPathConstants.STRING).toString();
EDIT: Here is a test code that proves my point:
String a ="<?xml version=\"1.0\" encoding=\"UTF-8\"?><rss xmlns:dc=\"http://purl.org/dc/elements/1.1/\" xmlns:sy=\"http://purl.org/rss/1.0/modules/syndication/\" xmlns:admin=\"http://webns.net/mvcb/\" xmlns:atom=\"http://www.w3.org/2005/Atom/\" xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\" xmlns:content=\"http://purl.org/rss/1.0/modules/content/\" xmlns:itunes=\"http://www.itunes.com/dtds/podcast-1.0.dtd\" version=\"2.0\"><channel><itunes:image href=\"http://icebox.5by5.tv/images/broadcasts/14/cover.jpg\" /></channel></rss>";
DocumentBuilderFactory xmlFact = DocumentBuilderFactory.newInstance();
xmlFact.setNamespaceAware(false);
DocumentBuilder builder = xmlFact.newDocumentBuilder();
XPathFactory xpathFactory = XPathFactory.newInstance();
String expr = "//channel/image/#href";
XPath xpath = xpathFactory.newXPath();
Document doc = builder.parse(new InputSource(new StringReader(a)));
String imageUrl = (String) xpath.compile(expr).evaluate(doc ,XPathConstants.STRING);
System.out.println(imageUrl);
The output is:
http://icebox.5by5.tv/images/broadcasts/14/cover.jpg

The XPath should include the root element, so rss/channel/itunes:image/#href.
Alternatively, you could start the xpath with a // so that all levels are searched for the xpath (//channel/itunes:image/#href) but if the root will always be the same it is more efficient to use the first option.