Passing JSON array from jsp to javascript using jquery

Question

I've searched for two days now and tried every possible thing I think. I use GSON to create a JSON array. When I print out my json string before sending it to Javascript via jquery it looks like this:

[{"var1":"hi","var2":"this","var3":"is"}]

Looks good to me. I've tried sending to js the following 2 ways:

String json = gson.toJson(googData, listType);
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(json);

and

String json = gson.toJson(googData, listType);
<%= json %>

Here's my js code:

$.getJSON("testgoogle.jsp", function(json) {
    $.each (json, function(k, v) {
        alert(v.val1);
    });
});

Pretty simple right? I can change it to $.get and see the string. If I alert(k) it only alerts 0 one time. I have a suspicion that i'm passing some white space with my json string. When I alert anything returned from the jsp's it appears lower in the alert box than say an alert("hi"). You know where the ! is in the alert box and how "hi" is right in the middle of the ! img. Well when I have <%= "hi" %> sent from jsp it is below the !. I moved <%= "hi" %> all the way to the top so my jsp looked like:

<%@page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%= "hi" %>

As you can see, I'm grasping at straws. This returned "hi" at the bottom of the !. The more lines in my jsp I move the "hi" down the lower it is in my alert box. Also, something weird. If I leave this at the top of my jsp:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

That will actually print out in my alert.

Please let me know if you need more info.

Solution: I was trying to call val1 when the key was var1. Wow! I will never get all those hours back ;) The correct code is identical to the above except val1 should be var1. Also, I tried it with eval(json) and it still worked FYI. Thanks for trying to help everyone!

as a sidenote, why do you do this from inside a JSP? The former code is identical to what you'd use in a servlet, which would a) be a lot cleaner and b) you wouldn't have to worry about things like white space generated by JSP directives & co. — fvu
– fvu, Commented Jun 29, 2012 at 21:41
I guess I just never thought to try. Are you talking about not using JQuery? — pnkflydgr
– pnkflydgr, Commented Jun 29, 2012 at 21:49
not at all, just suggesting you replace your server side JSON generating JSP by a plain servlet. JSPs are a view technology, there's not a lot to view here :-) — fvu
– fvu, Commented Jun 29, 2012 at 21:51
ouch, that sounds very painful - not familiar with WAS7, doesn't it support redeployment of wars? — fvu
– fvu, Commented Jun 29, 2012 at 22:05
Can i ask what the js would look like? I've mostly done Java programs and other scripting. What would the callback look like? $.getJSON("url_to_servlet".....? — pnkflydgr
– pnkflydgr, Commented Jun 29, 2012 at 22:12

Andreas · Accepted Answer · 2012-06-29 21:38:49Z

1

$.getJSON()

The success callback is passed the returned data, which is typically a JavaScript object or array as defined by the JSON structure and parsed using the $.parseJSON() method. It is also passed the text status of the response.

You don't have to "parse" the string yourself as it is already parsed by jQuery

$.getJSON("testgoogle.jsp", function(json) {
    $.each (json, function(k, v) {
        alert(v.val1);
    });
});

answered Jun 29, 2012 at 21:38

Andreas

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2 Comments

pnkflydgr Over a year ago

i'm not sure what you changed here? I tried this: $.getJSON("testgoogle.jsp", function(json) { alert(json.val1) It's undefined

Andreas Over a year ago

I've removed the 'eval(...)' as you've done it yourself. 'json' is an array so you'll have to use 'json[0].val1' if you're not going to use $.each anymore

Musa · Accepted Answer · 2012-06-29 21:37:11Z

0

In $.getJSON the json in function(json) { is alraedy a JavaScript object so you don't eval it

answered Jun 29, 2012 at 21:37

Musa

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1 Comment

pnkflydgr Over a year ago

Yea. I tried that. I've tried 100's of variations of the js syntax it seems. I even tried $.makeArray and $.map.

Ali Murtaza Shaikh · Accepted Answer · 2012-06-29 22:40:40Z

0

Try this :

$.getJSON("testgoogle.jsp", function(json) {
$.each (json[0], function(k, v) {
    alert(v);
    });
});

answered Jun 29, 2012 at 22:40

Ali Murtaza Shaikh

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