how do I return two JSON arrays from an .ajax Call?

Question

I'm using jqPlot and since I can't find one decent place to find out how to send multiple series to jqplot through JSON, I will try to work around it.

so here's a little background:

Right now, I can call my servlet and return a JSON array with the data that I'm going to display in the chart.

AJAX CALL

$.ajax({
            type:   'POST',
            cache:  'false',
            data:   params,             
            url:    '/miloWeb/PlotChartServlet',
            async:  false,
            dataType: 'json',
            success: function(series){                  
                coordinates =  [series] ;
            },
            error: function (xhr, ajaxOptions, thrownError){
                alert(ajaxOptions);
            }   
        });

SERVLET

    private void generateCoordinates(HttpServletRequest request, HttpServletResponse response) throws IOException{

    JSONArray coordinates = new JSONArray();
    try {
        coordinates = findChartCoordinatesByPatientPK();
    } catch (JSONException e) {
        e.printStackTrace();
    }
    response.getOutputStream().print(coordinates.toString());

}

What this does is return the string:

[["07/06/2000","22.0"],["08/06/2000","20.0"],["08/06/2003","15.0"],["08/06/2005","35.0"],["08/06/2007","12.0"],["08/06/2010","10.0"],["08/06/2012","10.0"]]

So I store that in the variable 'coordinates' and use those to plot the jqPlot graph using:

var plot10 = $.jqplot ('chartdiv', coordinates);

Up To this point everything works great, now comes what I'm trying to achieve:

If I hardcode a String that symbolizes the two arrays inside another array, like so:

[[["07/06/2000","22.0"],["08/06/2000","20.0"],["08/06/2003","15.0"],["08/06/2005","35.0"],["08/06/2007","12.0"],["08/06/2010","10.0"],["08/06/2012","10.0"]], [["07/06/2000","21.0"],["08/06/2000","19.0"],["08/06/2003","14.0"],["08/06/2005","34.0"],["08/06/2007","11.0"],["08/06/2010","9.0"],["08/06/2012","9.0"]]]

I can get the jQplot to plot the two distinct lines in the chart! So I tried doing the same and returning a String exactly like that one through the servlet:

NOT WORKING SERVLET

    private void generateCoordinates(HttpServletRequest request, HttpServletResponse response) throws IOException{
        JSONArray coordinates = new JSONArray();
        JSONArray coordinates2 = new JSONArray();
        try {
            coordinates = VitalsBB.findChartCoordinatesByPatientPK();
            coordinates2 = VitalsBB.findChartCoordinatesByPatientPK2();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        response.getOutputStream().print( coordinates.toString() + ", " + coordinates2.toString());

    }

But that doesn't work, it gives me a parse Error. So do I need to modify the AJAX call? or is there a way to give back two JSON arrays.toString() to my form and store them in a variable? Or maybe I need two variables?

Did you try wrapping the output with '[' and ']'? Notice that you need this for it to be a JSON array. — TheZ
– TheZ, Commented Jul 11, 2012 at 20:57
that was IT, hourse spent on something soooooooo basic. THANK YOU — Myy
– Myy, Commented Jul 11, 2012 at 21:09
If it works before, and you change something, always check where you just made the change in logic. It is likely the culprit code :) — TheZ
– TheZ, Commented Jul 11, 2012 at 21:13

pb2q · Accepted Answer · 2012-07-11 21:03:40Z

7

You're not enclosing the two sub-arrays in outer array brackets when you call response.getOutputStream().print().

Try this instead:

response.getOutputStream().print("[" + coordinates.toString() + ", " + coordinates2.toString() + "]");

If your code worked when you hardcoded the array, then this should work.

edited Jul 11, 2012 at 21:03

answered Jul 11, 2012 at 20:57

pb2q

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1 Comment

Myy Over a year ago

Thanks pb2q, that was it, I am so grateful!

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