I spent about an hour to do some blog reading. Around two weeks ago I left a comment in Patrick Logan's (an open-source developer) blog on More on the ESB. And just now, while rolling through the feeds consumed by the demon, I found a very good blog by Steve Vinoski (former chief engineer of IONA Technologies) in response to Patrick's blog -- The ESB question. His answer to the problems is REST. Steve subsequently wrote another two blog entries.
Bob Warfield of SmoothSpan summarized the discussion and stretched on multiple language approach as solution to enterprise problems, see ESB vs REST (Another Case for Multi-Language Programming).
They are very good reads which create room for me to start thinking again.
Lately, I am working on the JIRA Transport for Mule and one of the cool things about it is it reads JSON defined at the endpoint, then parses it to invoke the SOAP service of JIRA. I have never been a fan of writing SOAP client using Java and I hate the stubs, it is always Python or Perl.
- yc, reading
Showing posts with label json. Show all posts
Showing posts with label json. Show all posts
Tuesday, October 16, 2007
Monday, July 2, 2007
Son oh son.. JSON
Learning a new techy stuff every weekend of mine seems to have turned into a real habit. JSON (or you can call it Jason ;-)), not something entirely new but it has been really hot these days. It stands for "JavaScript Object Notation" and it exists today is to make the AJAX programmers life easier.
I will briefly show you how you can get a hang of it using a simple JSP file and a small piece of JavaScript (YUI). If you do not have an idea about AJAX yet, you'd probably want to read about it first before going beyond this paragraph.
An AJAX response in XML format requires writing client code to parse it into DOM model, for instance:
Then some annoying JSDom bits to extract the data, which I'm not going to write. As I could recall, my last time of writing AJAX and DOM stuffs was a year ago for a Java webapp which requires validating the form fields by sending synchronous request to webMethods endpoints.
This might just be another article about JSON which you have read before from other sites, yes, it is. Anyway, a response can also be sent in JSON (which is basically string then be evaluated using JavaScript eval() method), e.g.
Data can then be extracted easily unlike DOM, e.g.
Before I end this blog so that you can find out more by yourself ;-), this is the JSP used to generate the response:
One final and common note though, if you ever come across designing a webapp with AJAX functionality, do keep the response format consistent, i.e. use application/xml OR text/json NOT both, so that you will not confuse the developers at another end of which they should expect.
- yc, raining
I will briefly show you how you can get a hang of it using a simple JSP file and a small piece of JavaScript (YUI). If you do not have an idea about AJAX yet, you'd probably want to read about it first before going beyond this paragraph.
An AJAX response in XML format requires writing client code to parse it into DOM model, for instance:
<bean>
<name>foo</name>
<description>foobar</description>
<id>10000</id>
</bean>
Then some annoying JSDom bits to extract the data, which I'm not going to write. As I could recall, my last time of writing AJAX and DOM stuffs was a year ago for a Java webapp which requires validating the form fields by sending synchronous request to webMethods endpoints.
This might just be another article about JSON which you have read before from other sites, yes, it is. Anyway, a response can also be sent in JSON (which is basically string then be evaluated using JavaScript eval() method), e.g.
{"name": "foo",
"description": "foobar",
"id": "10000"}Data can then be extracted easily unlike DOM, e.g.
var jsonObj = eval("(" + responseText + ")");
var name = jsonObj.name;Before I end this blog so that you can find out more by yourself ;-), this is the JSP used to generate the response:
<%@ pageAnd this is the HTML used to send the request and receive the response:
language="java" contentType="text/json; charset=utf-8"
import="org.json.simple.JSONObject"
%>
<% response.setContentType("text/json; charset=utf-8"); %>
<%
JSONObject jsonObj = new JSONObject();
jsonObj.put("name", request.getParameter("name"));
jsonObj.put("description", request.getParameter("description"));
jsonObj.put("id", new Long(request.getParameter("id")));
out.print(jsonObj);
out.flush();
%>
<html>
<head>
<title>Test AJAX</title>
<script type="text/javascript" src="js/yui-2.2.2/yahoo/yahoo-min.js"></script>
<script type="text/javascript" src="js/yui-2.2.2/connection/connection-min.js"></script>
<script type="text/javascript">
function getAjaxRequest(url, callback){
return YAHOO.util.Connect.asyncRequest('POST', url, callback, "name=foo&description=foobar&amp;id=10000");
}
</script>
</head>
<body>
<script type="text/javascript">
var callback = {
success: function(o){ alert("Successful: \n" + o.responseText + "\n" + o.getAllResponseHeaders)
var jsonObj = eval("(" + o.responseText + ")");
// Some reflection here
var jsonDump = "";
for(key in jsonObj){
jsonDump += key + ": " + jsonObj[key] + "\n";
}
alert(jsonDump);
},
failure: function(o){ alert("Failed: \n" + o) },
argument: []
}
getAjaxRequest("testJsonResponse.jsp", callback);
</script>
</body>
</html>
One final and common note though, if you ever come across designing a webapp with AJAX functionality, do keep the response format consistent, i.e. use application/xml OR text/json NOT both, so that you will not confuse the developers at another end of which they should expect.
- yc, raining
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