I am creating a xml request using java.
I am new in creating xmls using java.
Here is code:
Document doc = docBuilder.newDocument();
Element rootElement = doc.createElement("UserRequest");
rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:ns0", "https://com.user.req");
rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
doc.appendChild(rootElement);
// user element
Element user = doc.createElement("User");
rootElement.appendChild(user);
// userAttributes element
Element userAttr = doc.createElement("UserAttributes");
rootElement.appendChild(userAttr);
// name elements
Element name = doc.createElement("Name");
name.appendChild(doc.createTextNode("hello"));
userAttr.appendChild(name);
// value elements
Element value = doc.createElement("Value");
name.appendChild(doc.createTextNode("dude"));
userAttr.appendChild(value);
Expected output:
<?xml version="1.0" encoding="UTF-8"?>
<UserRequest
xmlns:ns0="https://com.user.req"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns0:UserRequest">
<User/>
<UserAttributes>
<Name>hello</Name>
<Value>dude</Value>
</UserAttributes>
</UserRequest>
Generated output:
<?xml version="1.0" encoding="UTF-8"?>
<UserRequest
xmlns:ns0="https://com.user.req"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
<User/>
<UserAttributes>
<Name>hello</Name>
<Value>dude</Value>
</UserAttributes>
</UserRequest>
How to get correct namespace (as shown at expected section).
There's nothing wrong with the namespaces in your generated output. However this is an accident ... you're using setAttributeNS() to do something it's not intended for.
Read up on XML namespace declarations and namespace prefixes. That will be a lot easier than trying to explain point-by-point why you're not getting what you expected. For example, xmlns is not a namespace prefix, and xsi:type is not a namespace.
Instead of trying to create the desired namespace declarations as if they were normal attributes, delete these two lines
rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/",
"xmlns:ns0", "https://com.user.req");
rootElement.setAttributeNS("http://www.w3.org/2000/xmlns/",
"xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
and instead use
rootElement.setAttributeNS("http://www.w3.org/2001/XMLSchema-instance",
"xsi:type", "ns0:UserRequest");
This should give you most of your expected output, except for the ns0 namespace prefix declaration. It won't generate that because you're not using ns0 on any element or attribute. Did you mean to have
<ns0:UserRequest ...
in your expected output?
Related
I have exception like this:
javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"tax"). Expected elements are <{}TaxGroup>
I have resposne which is String and look like this:
<?xml version="1.0" encoding="utf-8"?>
<tax xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<xml_message_type>tax</xml_message_type>
<version>
<xml_version>1.0</xml_version>
</version>
</tax>
How to iterate over this XML and repleace tag name tax with TaxGroup ?
It must mean that you try to unmarshal your XML which has a root element <tax> to Java Jaxb class which expects root element <TaxGroup> instead.
Definitelly XML does not match what unmarshaler was requested.
check what Java class do you expect to get out of this XML, and change it accordingly. Also check what element name defined in its JAXB annotation.
I'm attempting to use JDOM2 in order to extract the information I care about out of a XML document. How do I get a tag within a tag?
I have been only partially successful. While I have been able to use xpath to extract <record> tags, the xpath query to extract the title, description and other data with in the record tags has been returning null.
I've been using Xpath successfully to extract <record> tags out of the document. To do this I use the follwing xpath query: "//oai:record" where the "oai" namespace is a namespace I made up in order to use xpath.
You can see the XML document I'm parsing here, and I've put a sample below: http://memory.loc.gov/cgi-bin/oai2_0?verb=ListRecords&set=cwp&metadataPrefix=oai_dc
<record>
<header>
<identifier>oai:lcoa1.loc.gov:loc.pnp/cph.3a02293</identifier>
<datestamp>2009-05-27T07:22:37Z</datestamp>
<setSpec>cwp</setSpec>
<setSpec>lcphotos</setSpec>
</header>
<metadata>
<oai_dc:dc xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
<dc:title>Jubal A. Early</dc:title>
<dc:description>This record contains unverified, old data from caption card.</dc:description>
<dc:date>[between 1860 and 1880]</dc:date>
<dc:type>image</dc:type>
<dc:type>still image</dc:type>
<dc:identifier>http://hdl.loc.gov/loc.pnp/cph.3a02293</dc:identifier>
<dc:language>eng</dc:language>
<dc:rights>No known restrictions on publication.</dc:rights>
</oai_dc:dc>
</metadata>
</record>
If you look in the larger document you will see that there is never a "xmlns" attribute listed on any of the tags. There is also the matter of there being three different namespaces in the document ("none/oai", "oai_dc", "dc").
What is happening is that the xpath is matching nothing, and evaluateFirst(parent) is returning null.
Here is some of my code to extract the title, date, description etc. out of the record element.
XPathFactory xpf = XPathFactory.instance();
XPathExpression<Element> xpath = xpf.compile("//dc:title",
Filters.element(), null,
namespaceList.toArray(new Namespace[namespaceList.size()]));
Element tag = xpath.evaluateFirst(parent);
if(tag != null)
{
return Option.fromString(tag.getText());
}
return Option.none();
Any thoughts would be appreciated! Thanks.
In your XML, dc prefix mapped to the namespace uri http://purl.org/dc/elements/1.1/, so make sure you declared the namespace prefix mapping to be used in the XPath accordingly. This is part where the namespace prefix declare in your XML :
<oai_dc:dc
xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/
http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
XML parser only see the namespace explicitly declared in the XML, it won't try to open the namespace URL since namespace is not necessarily a URL. For example, the following URI which I found in this recent SO question is also acceptable for namespace : uuid:ebfd9-45-48-a9eb-42d
I try to add new <class> elements to a persistence.xml file with JDOM2.
persistenceUnitEl.add(new Element("class").addContent(className));
The problem is that jdom2 always adds xmlns="" to the <class> elements.
How can i prevent this?
removeAttribute("xmlns") does not work and removeNameSpace(el.getNameSpace()) also does not work.
JDOM only adds the xmlns="" if you add child elements to other elements that are already in a namespace. The default Namespace in XML is the one which has no prefix. In the following example:
<root>
<child />
</root>
There are no namespace prefixes, and the default namespace is "".
The above XML snippet is semantically identical to:
<root xmlns="" >
<child />
</root>
The xmlns="" means that, any time you see an element that has no prefix, that you should put it in the 'empty' namespace "".
Now, if you want to put things in a namespace, and have a prefix, you would do:
<ns:root xmlns:ns="http://mynamespace">
<ns:child />
</ns:root>
Note that the root and child elements in the above example are in the namespace http://mynamespace, and that namespace has the prefix ns. The above code would be semantically identical to (has the same meaning as):
<root xmlns="http://mynamespace">
<child />
</root>
In the above example, the default namespace is changed from "" to be http://mynamespace, so now elements that have no prefix are in that default namespace http://mynamespace. To reiterate, the following two documents are identical:
<ns:root xmlns:ns="http://mynamespace">
<ns:child />
</ns:root>
and
<root xmlns="http://mynamespace">
<child />
</root>
Now, what does all of this have to do with your problem?
Well, your element persistenceUnitEl must be in a default namespace that is not "". Somewhere on that element, or on of it's parents, you have something like:
<tagname xmlns="...something....">
<PersistenceUnit>
</PersistenceUnit>
</tagname>
In the above, the PersistenceUnit is in the namespace ...something..... Now, you are asking JDOM to add the element new Element("class") to the document, so you are getting:
<tagname xmlns="...something....">
<PersistenceUnit>
<class xmlns="" />
</PersistenceUnit>
</tagname>
The reason is because you are telling JDOM to put it in the "" namespace (Namespace.NO_NAMESPACE). See the documentation for JDOM here: new Element(String name).
instead, what you want to do, is put it in the same namespace as the parent:
Namespace parentNamespace = persistenceUnitEl.getNamespace();
persistenceUnitEl.add(new Element("class", parentNamespace).addContent(className));
Now, the real question is whether the "class" element actually belongs in the same namespace as the parent, or not. But that is a question only you can answer.
Resources:
Namespace specification
Decent introduction
A tutorial (quite advanced)
JDOM's NamespaceAware documentation
JDOM's FAQ
From my understanding, I think this is what you want.
<RootTagname xmlns="...some namespace....">
<SubTag>
<NewElement yourAttrib="1"/>
</SubTag>
</RootTagname >
This is what you get.
<RootTagname xmlns="...some namespace....">
<SubTag>
<NewElement xmlns="" yourAttrib="1"/>
</SubTag>
</RootTagname >
Use the below snippet to create the new Element
Element newElement = new Element("NewElement", subElement.getNamespace());
Here is the full code.
Namespace namespace = Namespace.getNamespace("prefix", ".....some namespace....");
XPathBuilder<Element> subTagXpathelementBuilder = new XPathBuilder<Element>("//prefix:SubTag", Filters.element());
subTagXpathelementBuilder.setNamespace(namespace);
XPathFactory xpathFactory = XPathFactory.instance();
Document doc = (Document) builder.build(xmlFile);
XPathExpression<Element> xpath = subTagXpathelementBuilder .compileWith(xpathFactory);
List<Element> subElementsList = xpath.evaluate(doc);
for (Element subElement : subElementsList ) {
Element newElement = new Element("NewElement", subElement.getNamespace());
List<Attribute> newElementAttribList = newElement.getAttributes();
newElementAttribList .add(new Attribute("yourAttrib", "1"));
subElement .addContent(newElement);
}
I have below XML which contains a default namespace
<?xml version="1.0"?>
<catalog xmlns="http://www.edankert.com/examples/">
<cd>
<artist>Stoat</artist>
<title>Future come and get me</title>
</cd>
<cd>
<artist>Sufjan Stevens</artist>
<title>Illinois</title>
</cd>
<cd>
<artist>The White Stripes</artist>
<title>Get behind me satan</title>
</cd>
</catalog>
And Im running following code expecting some result in return
Element rootElem = new Builder().build(xml).getRootElement();
xc = XPathContext.makeNamespaceContext(rootElem);
xc.addNamespace("", "http://www.edankert.com/examples/");
Nodes matchedNodes = rootElem.query("cd/artist", xc);
System.out.println(matchedNodes.size());
But the size is always 0.
I gone through
https://stackoverflow.com/a/9674145/1160106 [I really didnt get the weired xpath syntax]
http://www.edankert.com/defaultnamespaces.html#Jaxen_and_XOM [Can see some hope. Just requires a major change in my current implementation]
Looking forward for any help.
Unprefixed names in XPath always mean "no namespace" - they don't respect the default namespace declaration. You need to use a prefix
Element rootElem = new Builder().build(xml).getRootElement();
xc = XPathContext.makeNamespaceContext(rootElem);
xc.addNamespace("ex", "http://www.edankert.com/examples/");
Nodes matchedNodes = rootElem.query("ex:cd/ex:artist", xc);
System.out.println(matchedNodes.size());
It doesn't matter that the XPath expression uses a prefix where the original document didn't, as long as the namespace URI that is bound to the prefix in the XPath namespace context is the same as the URI that is bound by xmlns in the document.
I am trying to evaluate XPath Expression "/feed/entry/title" using:
NodeList nodeList = (NodeList) inputXMLxpath.evaluate("/feed/entry/title", xmlDoc,
XPathConstants.NODESET);
If the xmlDoc is like this:
<?xml version="1.0" encoding="UTF-8"?>
<feed>
<entry>...
<feed>
I get proper results, but when xmlDoc is like this:
<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="en-US">
<entry>...
</feed>
the result of XPath evaluation is always an empty list.
Can anybody tell the reason for this and suggest a solution such that I get proper result in second case also?
The xmlns-"...." is a namespace declaration, and it has the effect of changing the names of the elements in the document so that they are no longer called "feed" and "entry", but something more complicated. Google for "XPath default namespace declaration".