create javascript array in json response in Java

Question

I have a servlet where I send JSON response (back to javascript) . For example , my response looks like

{
    "responseStr":"1,5,119.8406677,7,7,116.5664291,10,10,116.6099319,20,10,117.2185898,25,3,115.2636185"
}

Now what is happening at the moment is that I am collecting data( numbers above) in servlet and sending it in JSON response as a String with comma separated values. When this response reaches front end, all these numbers have to go in a javascript array (where I do my further logic). Currently I am doing this by

var res = JSON.parse(REQ.responseText);         
var myArr = res.responseStr.split(',');

My thinking is that the second line( where I use split()) is causing a bottleneck in my application . A few data points as in above example are not a trouble but it becomes a problem when i have thousands of data points.

So my question is that is there a way that when I am creating my response in servlet that I can create the response as javascript array so that I do not have to use split() at all? Any better ways of achieving the above task of converting the response into javascript array?

Answer 1

If you send responseStr as an Array, when the JSON parses it, it will be an array. So you could send your JSON response as "[1,2,3,4,5,6,7]" and so one, and when you JSON.parse, it will return an array.

To make it a little more clear :

var arr = [1,2,3,4,5];
arr = JSON.stringify(arr); // "[1,2,3,4,5]" -- String
arr = JSON.parse(arr); // [1,2,3,4,5] -- Array

Answer 2

In your response set content-type JSON/application and send JSON array

{
    "responseStr":["1","5","119.8406677","7","7","116.5664291","10","10","116.6099319","20","10","117.2185898","25","3","115.2636185"]
}

Then in your JavaScript you can simply use (reference):

var myArray = responseJSONObject.responseStr;

You may utilize JSON.js for various tasks.

Answer 3

That is a great question. JSON can return an array as simply as

{ "responseStr": [[1], [2], [3], [4] }

Cool!

Double Quotes are not necessary unless you want them as strings.

One more thing, you can have multi dimensional arrays too!

{ "responseStr": [[1,10], [2,20], [3,30], [4,40]] }

This link is a great reference:

http://json.org/fatfree.html