Building a JSON web service with Java and Axis2

【http://www.marcusschiesser.de/2009/01/building-a-json-web-service-with-java-and-axis2/】

Building a JSON web service with Java and Axis2
Januar 23rd, 2009 · 9 Comments
It is said that in Java usually theeasiest things are the hardest. The following is a nice example as it took mesome time to figure out how to do it.

I wanted to build a simple URL request based web service in Java that returnsan JSON object. Yes, you can do that with a simple Servlet too, the advantageof using Axis2 isthat you can also call your deployed services
using SOAP without anyconfiguration changes.
1.
Download Axis2 as WAR and install it inyour servlet container
2.
Download the DynamicResponseHandler module andadd it to Axis by copying it to WEB-INF/modules
3. PatchJettison or download my patched version and replaceit with the one installed
in WEB-INF/lib
4. Add the DynamicResponseHandler modulereference to the axis2.xml configuration (located in WEB-INF/conf):
<module ref="DynamicResponseHandler"/>
5. Add the JSON Message formatters to theaxis2.xml:
<messageFormatter contentType="application/json" class="org.apache.axis2.json.JSONMessageFormatter"/>
<messageFormatter contentType="application/json/badgerfish" class="org.apache.axis2.json.JSONBadgerfishMessageFormatter"/>
6. Add JSON Message builders to theaxis2.xml:
<messageBuilder contentType="application/json" class="org.apache.axis2.json.JSONOMBuilder"/>
<messageBuilder contentType="application/json/badgerfish" class="org.apache.axis2.json.JSONBadgerfishOMBuilder"/>
7. Start your servlet container and testthe standard version service by calling this url:

http://localhost:8080/axis2/services/Version/getVersion?response=application/json
Now you are ready to add your own webservices. Here you can find an examplehowto deploy a simple POJO service. Have fun!
Update: Zeno (see comments) sent me patch for usage with Jettison 1.2 –otherwise he received a NullPointerException. I haven’t checked it, but
I hopeit helps you! Thanks Zeno!

【http://markmail.org/message/cu2tw43qnrqgqgwp】

Subject:	[jettison-dev] JSON
From:	Cristian Bullokles (cris...@gmail.com)
Date:	May 6, 2008 7:34:35 pm
List:	org.codehaus.jettison.dev

Jettison users/dev,
I've started using axis2and enabling JSON support for some
services. (as you know axis2 uses jettison to parse json messages)
I'd like to useparticularly the mapped format with my services,
but when I've tried to use this format, I allways received the same error:
Mapped formatted JSON withnamespaces are not supported in Axis2.
Make sure that your request doesn't include namespaces or use theBadgerfish
convention.
Debugging the code, theerror is generated when the jettison tried
to get the namespace, particularly in MappedNamespaceConvention.java file.
I've modified thisfunction in that way and all started working
fine.

private StringgetJSONNamespace(String ns) {
if (ns == null ||ns.length() == 0) return "";

String jns = (String)xnsToJns.get(ns);
if (jns == null) {
return "";
// throw newIllegalStateException("Invalid JSON namespace: " +
ns);
}
return jns;
}

I've recompiled jettisonand all works fine, and past all unit
test created.
You think this could be a problem forother kinds of messages or
this is a patch that could be applied in future versions.
Regards
Cristian