Send values from jsp to Servlet

Question

i have a jsp in which i have select tag and i want to get the and the value selected from the select in jsp in my Servlet

<select id="listoffood" name="dropdown" onchange="foodname();">
<option value="bg">Burger</option>
<option value="pas">pasta</option>
<option value="pi">pizza</option>
</select>
<div id='content'></div>

here is the javascript code

function foodname()
{

  var xmlHttpReq = false;
    var self = this;
    document.getElementById('content').innerHtml='';
    // Mozilla/Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // IE
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    }

    self.xmlHttpReq.open('GET', "InformationServlet", true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.send(null);

    self.xmlHttpReq.onreadystatechange= function ()
    {
        //alert(document.getElementById('content'));
        if (self.xmlHttpReq.readyState==4)
        {
        if (self.xmlHttpReq.status == 200)
        {

        document.getElementById('content').innerHTML=self.xmlHttpReq.responseText;
        }
        }
    };

}

What i have done is used a get Attribute like this but it aint working its showing null

protected void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException 

    {
    // TODO Auto-generated method stub

    String coun = request.getParameter("dropdown");
    PrintWriter out=response.getWriter();
    System.out.println("here : "+coun);
}

Thanks in advance and any piece of code is highly appreciated.

what does method `foodName()` do? Is your select inside `form`? — Kshitij, May 03 '13 at 10:50
#kshitj food name goes to javascript and js than calls servlet by ajax. @Baadshah yes it goes to same servlet on onChange method — Anish Sharma, May 03 '13 at 10:52
Are you able to get other parameters from this JSP page in your servlet ? — Ankit Singla, May 03 '13 at 10:58
i dnt have any html form i just have a select tag on my jsp @AnkitSingla i dont have ant other parameters on my jsp its jusst the select tag — Anish Sharma, May 03 '13 at 10:59
Post your javascript function, if you are using POST it won't work — Alexandre Lavoie, May 03 '13 at 11:00
Please, post the code related to the complete flow. Making us guess won't help you as much as we can. — Ravi K Thapliyal, May 03 '13 at 11:00
@AlexandreLavoie i know it wont work with the post method i am using Get method — Anish Sharma, May 03 '13 at 11:02

Ravi K Thapliyal · Accepted Answer · 2013-05-03T12:29:09.643

1

Just change your AJAX open() request as

var select = document.getElementById("listoffood");
self.xmlHttpReq.open('GET', "InformationServlet?dropdown=" + select.options[select.selectedIndex].value, true);

edited May 03 '13 at 12:29

answered May 03 '13 at 11:49

Ravi K Thapliyal

51,095
9
76
89

its http://localhost:8080/Distributor/InformationServlet and its showing an error in the code u gave.. the error is cannot read property 'undefined' of undefined – Anish Sharma May 03 '13 at 12:09
nothing is wrong with the url its showing errror in js.. i have mentioned the error in my previous comment – Anish Sharma May 03 '13 at 12:14
@AnishSharma Did you try with `var select`. – Ravi K Thapliyal May 03 '13 at 12:28
yes i did it than shows cannot read property "options" of the undefined – Anish Sharma May 03 '13 at 12:35
@AnishSharma I just tested the code and successfully did a GET for `http://www.google.com/search?q=pasta`. Can you do an `alert(document.getElementById("listoffood"));` As per your HTML this shouldn't be `undefined`. Please verify. (two "f"s here) – Ravi K Thapliyal May 03 '13 at 12:48
Thanks it worked i was making a mistake i commented one line by mistake.. That was all it – Anish Sharma May 06 '13 at 06:16
Ah, glad it worked! I was wondering what went wrong since I'd tested my solution successfully. If you found this helpful can you please consider giving an up vote as well. – Ravi K Thapliyal May 06 '13 at 07:07
i have one more question in case if u r interested in answering.. i am posting the link http://stackoverflow.com/questions/16397207/iterate-arraylist-in-jsp – Anish Sharma May 06 '13 at 10:55

score 0 · Answer 2 · answered May 03 '13 at 11:00

0

Use method getParameterValues(String).
This is because <select> tag can have multiple selected values (e.g. select multiple)

String[] coun = request.getParameterValues("dropdown");

answered May 03 '13 at 11:00

Ilya

29,135
19
110
158

I knew somebody will post this. `multiple` is not true for `select`. – Ravi K Thapliyal May 03 '13 at 11:02

score 0 · Answer 3 · edited May 23 '17 at 12:28

0

Check this post:

How to use onClick() or onSelect() on option tag in a JSP page?

You seems to be using select tag without any action such as onchange

edited May 23 '17 at 12:28

Community

1
1

answered May 03 '13 at 11:01

Juned Ahsan

67,789
12
98
136

`onchange=foodname();` I think you missed seeing that! – Ravi K Thapliyal May 03 '13 at 11:03
@AnishSharma Using a event handler on `select` is fairly common and not the problem here. You don't need to change that. – Ravi K Thapliyal May 03 '13 at 11:13

score 0 · Answer 4 · answered May 03 '13 at 11:03

0

You can get selected item text from list box using

var e = document.getElementById("dropdown");
var selectedValue = e.options[selectBox.selectedIndex].value

in your JS method and send this value with servlet's link.

answered May 03 '13 at 11:03

Ankit Singla

198
2
15

how can i send the value with servlet link – Anish Sharma May 03 '13 at 11:06
InformationServlet?dropdown=selectedValue And use request.getParameter("dropdown"); in your servlet as you have already done. – Ankit Singla May 03 '13 at 11:10
Distributor index.jsp InformationServlet requestData.InformationServlet InformationServlet /InformationServlet – Anish Sharma May 03 '13 at 11:53
@AnishSharma Did you check my answer? – Ravi K Thapliyal May 03 '13 at 11:58
@AnishSharma : Have you given the correct package path for parameter ?? – Ankit Singla May 04 '13 at 04:33

score 0 · Answer 5 · answered May 03 '13 at 11:23

get the value from select tag

var e = document.getElementById("dropdown");
var selectedValue = e.options[selectBox.selectedIndex].value;

and edit js function

self.xmlHttpReq.open('GET', "InformationServlet?dropdown="selectedValue , true);

finally your should looks like

function foodname()
{

    var e = document.getElementById("dropdown");
    var selectedValue = e.options[selectBox.selectedIndex].value;

  var xmlHttpReq = false;
    var self = this;
    document.getElementById('content').innerHtml='';
    // Mozilla/Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // IE
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    }

    self.xmlHttpReq.open('GET', "InformationServlet?dropdown="selectedValue , true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.send(null);

    self.xmlHttpReq.onreadystatechange= function ()
    {
        //alert(document.getElementById('content'));
        if (self.xmlHttpReq.readyState==4)
        {
        if (self.xmlHttpReq.status == 200)
        {

        document.getElementById('content').innerHTML=self.xmlHttpReq.responseText;
        }
        }
    };
}

can you share your web.xml file – NPKR May 03 '13 at 11:50 — NPKR, May 03 '13 at 11:50

Send values from jsp to Servlet

5 Answers5