Jersey 2 - JAXB - jaxb

Using Jersey 2 m13-3 in Tomcat 7, I'm trying to post XML and have JAXB automatically unmarshal it.
My method signature is something like:
#POST
#Consumes(MediaType.APPLICATION_XML)
#Produces( {"text/xml"})
public Response setFoo(
myXJC.generatedclass.Foo foo
)
I get a 400 bad request, but no exception (that I can find).
Testing with:
#POST
#Consumes(MediaType.APPLICATION_XML)
#Produces( {"text/xml"})
public Response setFoo() { ... }
I'm confident this method is being invoked in response to a request.
But as soon as I add arg myXJC.generatedclass.Foo, it isn't.
Do I need something special in my class which extends javax.ws.rs.core.Application to use JAXB? Something ResourceConfig related perhaps? Any extra jersey specific jars?
I see there is a jersey-media-moxy. I'd be happy to get it working with MOXy, but ideally it would also work with Sun/Oracle JAXB.
I've had a look at the source code of:
<dependency>
<groupId>org.glassfish.jersey.examples</groupId>
<artifactId>jaxb</artifactId>
<version>2.0-m13-3</version>
</dependency>
but I'm still having trouble.

Turns out that when I generated the classes from my XSD using XJC, I'd left an incorrect target namespace in there.
The XML I was posting was not namespace qualified, but the generated classes were expecting a namespace.
Once I fixed this, things worked fine.

Related

No MessageBodyWriter for Single

I'm trying to use resteasy-rxjava2 to provide an XML document using jaxb, within a vertx application (using a non-vertx legacy library we have). But I get:
Could not find MessageBodyWriter for response object of type:
org.jboss.resteasy.rxjava2.propagation.ContextPropagatorOnSingleAssemblyAction$ContextPropagatorSingle of media type:
application/xml;charset=UTF-8
From what I can tell, this comes down to the difference between a MessageBodyWriter and the AsyncResponseProvider that is in the resteasy-rxjava2 dependency for a Single (SingleProvider).
I have the following resteasy service definition
#GET
#Path(FdsnwsPaths.QUERY)
#Produces(MediaType.APPLICATION_XML)
#Stream
// CHECKSTYLE:OFF too many parameters
public Response getQuery(...)
How do I get resteasy to properly serve the data asynchrously, using the SingleProvider or otherwise.
The #Get method must return the Single explicitly or it doesn't work. (Can't use Response or Object). In my case, the Single contains the jaxb xml root element.
#GET
#Path(FdsnwsPaths.QUERY)
#Produces(MediaType.APPLICATION_XML)
#Stream
public Single<FDSNStationXML> getQuery(...)
Then, to make things more complicated, in order to handle specific exception types and map them to specific response status codes, I have to create a custom ExceptionMapper which creates the Response object I used to be able to create directly in the method. (in resteasy-vertx, I found no documentation on how to do this, but in my case, I am creating my own VertxRestEasyDeployment object so I can register the class of the ExceptionMapper(s) like this:
VertxResteasyDeployment deployment = new VertxResteasyDeployment();
deployment.getActualProviderClasses().addAll(providerClasses);
For reference, this is all being done with:
RestEasy 5.0.3.Final (including resteasy-rxjava2)
RxJava 2.2.20
Vertx 3.9.5

How to customise the XML output of a Jersey JAXB serialisation

I have some #javax.xml.bind.annotation.Xml... annotated classes here intended for a RESt web service. Jersey is setup in a spring managed web container and the web service is returning a well formatted xml. We use the maven-enunciate-plugin to document the web service and create the xsd to the returned xml documents. I now would like to use the documentation xsd file as a schemaLocation within the returned xml file so that the xml validation won't complain about missing definions. How can I get the XML serialisation configured for this?
If I remember correctly, I had to do a few of things to get namespace identifiers properly written into my generated XML.
1) Created a JaxbFactory that configs and returns a custom marshaller (and unmarshaller, too, BTW). I'm omitting the getters/and unmarshalling setup below...
//constructor
public JaxbFactory() throws Exception {
context = JAXBContext.newInstance(ResourceDto.class);
// Setup the marshaller
marshaller = context.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
marshaller.setProperty(Marshaller.JAXB_SCHEMA_LOCATION, XmlMetadataConstants.XML_SCHEMA_LOCATION); // this schema location is used in generating the schema-location property in the xml
}
2) That factory class isn't "visible" to Jersey. To make it visible, I create a MarshallerProvider. That looks something like this:
#Provider
public class ResourceJaxbMarshallerProvider implements ContextResolver<Marshaller> {
// injected by Spring
private ResourceJaxbFactory ResourceJaxbFactory;
private ResourceStatusJaxbFactory ResourceStatusJaxbFactory;
/*
* ----------------------------------------
* Setters (for Spring injected properties)
* ----------------------------------------
*/
public void setResourceJaxbFactory(ResourceJaxbFactory ResourceJaxbFactory) {
this.ResourceJaxbFactory = ResourceJaxbFactory;
}
public void setResourceStatusJaxbFactory(ResourceStatusJaxbFactory ResourceStatusJaxbFactory) {
this.ResourceStatusJaxbFactory = ResourceStatusJaxbFactory;
}
/*
* ------------------------
* Interface Implementation
* ------------------------
*/
public Marshaller getContext(Class<?> type) {
if (type == ResourceDto.class)
return ResourceJaxbFactory.getMarshaller();
else if (type == ResourceStatusDto.class)
return ResourceStatusJaxbFactory.getMarshaller();
else
return null;
}
}
I've got Jersey wired into Spring using the Jersey/Spring Servlet so any #Provider class that gets created by Spring is automatically recognized by Jersey. In my Spring applicationContext.xml all I have to do is instantiate the resource provider. It will, in turn, go grab the marshaller from the factory.
3) The other thing that I found critical was that I had to create a package-info.java file in the root package containing my resource. Looks like this:
/*
* Note that this file is critical for ensuring that our ResourceDto object is
* marshalled/unmarshalled with the correct namespace. Without this, marshalled
* classes produce XML files without a namespace identifier
*/
#XmlSchema(namespace = XmlMetadataConstants.XML_SCHEMA_NAMESPACE, elementFormDefault = XmlNsForm.QUALIFIED)
package com.yourcompany.resource;
import javax.xml.bind.annotation.XmlNsForm;
At least I think that's everything I needed to do, I can't remember every single piece. I do remember that the package-info.java piece was the last critical cog that made it all come together.
Hope that helps. I spent wayyyy too much time digging for the info on all this. Jersey was seductively simple before I wanted it to do proper xml schema validation (and decent error reporting for schema-invalid input). Once I started down that road Jersey went from brain-dead easy to decently hard. The majority of that difficulty was sussing out all the details from the variety of posts online. Hopefully this will help get you farther, quicker. :-)

JAXB is not picking up #XmlJavaTypeAdapter

I have the following class that I need to serialize as XML:
#XmlAccessorType(XmlAccessType.FIELD)
public class Position {
#XmlElement(name = "Quantity", required = true)
private DecimalQuantity quantity;
...
}
I have put an XmlJavaTypeAdapter on the DecimalQuantity class because I want it to be serialized simply as a BigDecimal without the DecimalQuantity wrapper.
#XmlJavaTypeAdapter(DecimalQuantityAdapter.class)
#Embeddable
public class DecimalQuantity {
private BigDecimal value;
...
}
Here's the very simple DecimalQuantityAdapter class:
public class DecimalQuantityAdapter
extends XmlAdapter<BigDecimal, DecimalQuantity> {
public DecimalQuantity unmarshal(BigDecimal val) throws Exception {
return new DecimalQuantity(val);
}
public BigDecimal marshal(DecimalQuantity val) throws Exception {
return val.getValue();
}
}
I have a unit test that shows that the adapter is working correctly. The following Order object that has a DecimalQuantity gets serialized correctly (notice that this test class looks almost identical to the Position class above):
#XmlAccessorType(XmlAccessType.FIELD)
#XmlRootElement(name = "Order")
public class Order {
#XmlElement(name = "Quantity", required = true)
private DecimalQuantity quantity;
...
}
This gets serialized as shown below - no wrapper around the decimal number - life is good!
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Order>
<Quantity>10.2</Quantity>
</Order>
The trouble starts when I try to use DecimalQuantity in other maven projects. For example, the Position class shown at the beginning of this post is in a different maven project. The web service that uses the Position class is in yet another maven project. When the web service tries to deserialize DecimalQuantity, it does not know what DecimalQuantity is and is not able to pick up the DecimalQuantityAdapter. This is the error I get:
Caused by: javax.xml.bind.JAXBException:
class org.archfirst.common.quantity.DecimalQuantity nor any of its super class is known to this context.
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.getBeanInfo(JAXBContextImpl.java:594)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsXsiType(XMLSerializer.java:648)
... 53 more
I have event tried to add the #XmlJavaTypeAdapter annotation on the attribute itself, but JAXB does not pick it up. The only way to get rid of the exception is to put an #XmlSeeAlso({DecimalQuantity.class}) on the Position class itself. However, this disables the adapter and I get the following (undesired) serialization:
<Quantity xsi:type="ns2:decimalQuantity" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
Any idea where the problem is? I feel it has something to do with the visibility of JAXB annotations on DecimalQuantity and DecimalQuantityAdapter across packages/projects.
Thanks.
Naresh
Ok, I finally found the problem. My unit test was picking up the JAXB implementation in the Java runtime, whereas my real application (a web service) was picking up the JAXB implementation from GlassFish. Apparently the implementation bundled with GlassFish (2.2.1.1) cannot handle my use case. I proved it by forcing my unit test to use jaxb-impl-2.2.1.1.jar. Also it seems that the bug has been fixed in the latest JAXB implementation (2.2.3-1), but I am struggling to figure out how to replace GlassFish's implementation with this new version (see my post here).
Are you sure the problem is with the XmlJavaTypeAdapter for decimals, not the DecimalQuantity type. Because the exception you've posted is the one that happens when JAXB encounters a value of unknown class.
What happens if you omit the #XmlJavaTypeAdapter annotation? I know it probably can't work the way you intend, but what is the error message? Isn't it the same?
As you wrote the exception is gone when you added:
#XmlSeeAlso({DecimalQuantity.class})
I would leave the annotation in the code and try to find the reason why the adapter doesn't work.
Can you debug in the your XML adapter and/or add some trace output there, just to make sure the adapter really returns a non-empty String?

How can I tell Jersey to use my MessageBodyReader instead using JAXB?

Basically, I have some models which all use JAXB. However, I have some highly custom functionality to convert to JSON and back so I want to write my own MessageBodyReader/Writer to do the job for me.
Right now, the writing portion is done: if i return one of my models from a REST resource, it goes through my writer. But when I try and accept a model as a FormParam, it doesnt use my MessageBodyReader and instead attempts to unmarshal it using JAXB (which fails).
So how I can tell Jersey to use my Reader instead?
public TestModel testProvider(#FormParam("model") TestModel input){ //doesnt work
return new TestModel(); //this part works!
}
Mark as #Provider
Add the configuration to your web.xml EX:
<init-param><param-name>com.sun.jersey.config.property.packages</param-name> <param-value> your.package.that.contains.the.provider </param-value> </init-param>
Since your writer works, but your reader does not, I'm guessing you have just missed something in your configuration. Some things to check:
Do you have the #Provider annotation on your reader?
Did you correctly implement the isReadable method on your reader?
Do you have the appropriate #Consumes annotation on the reader, does its media type match the media type specified on your service method?

JAXB Unable To Handle Attribute with Colon (:) in name?

I am attempting to use JAXB to unmarshall an XML files whose schema is defined by a DTD (ugh!).
The external provider of the DTD has specified one of the element attributes as xml:lang:
<!ATTLIST langSet
id ID #IMPLIED
xml:lang CDATA #REQUIRED
>
This comes into the xjc-generated class (standard generation; no *.xjb magic) as:
#XmlAttribute(name = "xml:lang", required = true)
#XmlJavaTypeAdapter(NormalizedStringAdapter.class)
protected String xmlLang;
However, when unmarshalling valid XML files with JAXB, the xmlLang attribute is always null.
When I edited the XML file, replacing xml:lang with lang and changed the #XmlAttribute to match, unmarshalling was successful (i.e. attributes were non-null).
I did find this http://old.nabble.com/unmarshalling-ignores-element-attribute-%27xml%27-td22558466.html. But, the resolution there was to convert to XML Schema, etc. My strong preference is to go straight from an un-altered DTD (since it is externally provided and defined by an ISO standard).
Is this a JAXB bug? Am I missing something about "namespaces" in attribute names?
FWIW, java -version = "build 1.6.0_20-b02" and xjc -version = "xjc version "JAXB 2.1.10 in JDK 6""
Solved the issue by changing replacing xml: with a namespace declaration in the JAXB-generated class:
#XmlAttribute(name = "lang", namespace="http://www.w3.org/XML/1998/namespace", required = true)
Which makes sense, in a way.
Without this kind of guidance, how would JAXB know how to interpret the otherwise-undefined namespace xml:? Unless, of course, it implemented some special-case internal handling to xml: as done in http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamReader.html#getNamespaceURI%28java.lang.String%29 (see the first NOTE:)
Whether it's a bug in xjc's generation of the annotated objects or a bug in the unmarhaller, or simply requires a mapping somewhere in the xjc process is still an open question in my mind.
For now, it's working and all it requires is a little xjc magic, so I'm reasonably happy.
Disclaimer: Although 8 years late, I am adding this answer for lost souls such as myself trying to understand auto generation of java files from a DTD.
You can set project wide namespaces for the unmarshaller to work with directly in the project-info.java file via the #XmlSchema option.
This file should be automatically generated by xjc when generating classes from a schema, however it appears xjc does not automatically generate the package-info.java file when generating from a DTD!
However, you can manually make this file, and add it to the same package as the files generated by xjc.
The file would look like the following:
package-info.java :
#XmlSchema(
elementFormDefault=XmlNsForm.QUALIFIED,
xmlns = {
#XmlNs(prefix="xlink", namespaceURI="http://www.w3c.org/1999/xlink"),
#XmlNs(prefix="namespace2", namespaceURI="http://www.w3c.org/1999/namespace2")
})
package your.generated.package.hierarchy;
import javax.xml.bind.annotation.*;
You can add as many namespaces as required, simply add a new line in the form:
#XmlNs(prefix="namespace", namespaceURI="http://www.uri.to.namespace.com")
The benefit of doing it this way, rather than compared to editing the generated #XmlAttribute is that you do not need to change each generated XmlAttribute, and you do not need to manually remove the namespaces from the XmlAttribute name variable.

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