Hi
On 15/04/12 22:17, Ron Grabowski wrote:
writeXsiType=false gives the output I listed in my previous email. Its probably ok for what I need
to do but the "" seems to imply that "id" is a String rather than a number.
Maybe the json parser that will convert that back into a Java/.NET object will be forgiving and do
the right thing. Adding some sort of omitNullValues could help reduce the payload over the wire for
large lists of objects that contain mostly uninitialized properties. I don't know enough about CXF
to comment if that should be on the built-in JSONProvider.
I guess the only correct action in this case is to drop 'id' altogether
and the only way to do it with JSONProvider is to configure it to drop
'id' which is possible from Spring, but unfortunately is not (yet) from
CXFNonSpringJaxrsServlet.
I'm trying to retrofit an existing JAX-WS application (along with its jaxb
annotated generated entities) with JAX-RS support. I don't have the luxury of
being able to change the JAX-WS generated code. I'm finding that the jaxb
annotations are getting in the way...especially since many of the entities I
want to return in my JAX-RS code don't have XmlRootElement on them. Using the
GsonProvider below on both the server and client seems to bypass all the jaxb
stuff like I want (at least for producing entities, I haven't tried consuming
yet):
//inspired by
http://code.google.com/p/derquinse-commons/.../GenericGsonProvider.java
@Provider
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public class GsonProvider extends MessageBodyReaderWriter
{
@Override
protected void writeTo(Object item, Type type, Writer writer) throws
Exception {
getGson().toJson(item, type, writer);
}
@Override
protected Object readFrom(Reader reader, Type type) throws IOException,
WebApplicationException {
return getGson().fromJson(reader, type);
}
private Gson getGson() {
return new GsonBuilder().create();
}
}
I read through JSONProvider, AbstractJAXBProvider, and lots of the CXF test
cases. My GsonProvider class is bypassing 1,200+ lines of code in the built-in
CXF providers. Can you spot any obvious short-comings with my approach?
MessageBodyReaderWriter is just boiler plate code that implements the
interfaces for Object.
This approach looks fine to me. Try experimenting with the JAXB-enabled
Jackson provider too, not sure though what it does about xsi types
Cheers, Sergey
Thanks,
Ron
________________________________
From: Sergey Beryozkin<[email protected]>
To: [email protected]
Sent: Sunday, April 15, 2012 4:14 PM
Subject: Re: JAX-RS in v2.5.x: how to set custom JSONProvider(?) without Spring to stop
{"@xsi.nil":"true"}
On 15/04/12 21:07, Ron Grabowski wrote:
I have a feeling this is the best I can do with writeXsiType=false?
{"widget":{"id":"","name":"Hello World"}}
Is it what is happening after you've configured this option ?
There isn't a built-in option to omit the "id" entry entirely or set it to null?
you may also want to experiment with the CXF Transformation Feature
which does work with JSONProvider, but configuring this feature without
Spring may be tricky
As I said, you may also try other JSON providers if needed
Sergey
________________________________
From: Sergey Beryozkin<[email protected]>
To: [email protected]
Sent: Sunday, April 15, 2012 2:22 PM
Subject: Re: JAX-RS in v2.5.x: how to set custom JSONProvider(?) without Spring to stop
{"@xsi.nil":"true"}
Hi
On 15/04/12 19:09, Ron Grabowski wrote:
This post was helpful in showing how to set a custom JSONProvider both with and
without Spring:
http://stackoverflow.com/a/6344047
You can do:
<init-param>
<param-name>jaxrs.providers</param-name>
<param-value>
org.apache.cxf.jaxrs.provider.JSONProvider
(writeXsiType=false)
</param-value>
</init-param>
I updated that thread too
I'm assuming custom providers are registered before or override the built-in
ones so they get to inspect things first?
Yes
Here's some test cases explaining what I'm trying to do:
@Test // passes
public void JSONProviderIncludesNil() throws Exception {
JSONProvider p = new JSONProvider();
Widget widget = new Widget();
widget.setName("Hello World");
String json = toJson(p, widget, "widget", Widget.class);
assertEquals("{\"widget\":{\"id\":{\"@xsi.nil\":\"true\"},\"name\":\"Hello
World\"}}", json);
}
@Test // fails
public void OmitNillJSONProviderExcludesNil() throws Exception {
JSONProvider p = new OmitNillJSONProvider();
Widget widget = new Widget();
widget.setName("Hello World");
String json = toJson(p, widget, "widget", Widget.class);
assertEquals("{\"widget\":{\"name\":\"Hello World\"}}", json);
}
private<T> String toJson(JSONProvider p, T item, String root, Class<T>
classOfT) throws Exception {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
p.writeTo(
new JAXBElement<T>(new QName("", root), classOfT, item), // hack
???
classOfT, classOfT,
classOfT.getAnnotations(),
MediaType.APPLICATION_JSON_TYPE,
new MetadataMap<String, Object>(),
stream);
return stream.toString();
}
// yes, I know XmlRootElement is missing
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "widget", propOrder = {"id","name"})
public static class Widget {
@XmlElement(nillable = true) // can't change
protected Integer id;
@XmlElement(nillable = true) // can't change
protected String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class OmitNillJSONProvider extends JSONProvider {
// ???
}
Maybe I should bypass all this jaxb annotation sillyness and just let gson
handle serializing the object as if it didn't have any annotations?
JSONProvider is a default provider but if some other JSON provider can
handle this situation better, with or without JAXB, then it can be
easily registered too
HTH, Sergey
________________________________
From: Ron Grabowski<[email protected]>
To: "[email protected]"<[email protected]>
Sent: Saturday, April 14, 2012 10:17 PM
Subject: JAX-RS in v2.5.x: how to set custom JSONProvider(?) without Spring to stop
{"@xsi.nil":"true"}
I have objects with fields setup like this:
@XmlElement(nillable = true)
protected Integer id;
that I send out via JAX-RS with @Produces(MediaType.APPLICATION_JSON). The json
payload ends up like this when the fields aren't set:
"id":{"@xsi.nil":"true"}
I can't change the @XmlElement on the field because another part of my system
depends on it. I want to either output:
"id" : null
or ideally not output that field at all in the json payload. I think I need
extend the built in JSONProvder and tweak it (and/or Jettison) a little bit.
How can I do that without Spring? Can someone explain a solution both in terms
of web.xml and JAXRSServerFactoryBean (unit testing)?
Thanks,
Ron
--
Sergey Beryozkin
Talend Community Coders
http://coders.talend.com/
Blog: http://sberyozkin.blogspot.com
