How to access java.util.List session from javascript?

Question

In java my code is,

List abcList;   
request.getSession().setAttribute("abc", abcList);

I want to access this list in javascript,

var myVariable='<%=(List)session.getAttribute("abc")%>';

I am not getting the list(abcList) value in javascript......

Answer 1

You need to serialize your list to Javascript object. There are libraries that do it for you: https://stackoverflow.com/questions/338586/a-better-java-json-library

Answer 2

You have to write code that prints out the list as a javascript array. This propably just results in

var myVariable='ArrayList@123455'

but what you need is

var myVariable = ["element1", "element2, ...]

use a json serialization library. those do the printing for you. Or write a json printer, it's actually pretty straight forward^^.

Answer 3

You can't do that. You will have to create the list by iterating over the Java List. You can try something like this...

var myVar = [];
<%
List list = (List)session.getAttribute("abc");
for(int i = 0; i < list.size(); ++i){
    out.println("myVar.push('" + list[i] + "');");
}
%>

Answer 4

What exactly want to achieve ? Remember javascript will be executed on client browser where as the java code will be on the server. So you should not reference a java variable from javascript. Instead using jsp tags you can get the list only at the loading time that to on the server.