How can I access Java list elements from my client-side JavaScript code?
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20-09-2019 - |
Question
I have the following simple script, which I am using to dynamically create the list elements in a <ul>
<script type="text/javascript">
function generate(){
var arr = new Array();
<c:forEach items="${articles}" var="a" varStatus="status">
$('#listitems').append(
"<li>"+${a.title}+"</li>"
);
arr[${status.index}] ="${a.slideShow.images}";
</c:forEach>
}
</script>
My problem stems from the images attribute. Every article has a slideshow and every slideshow has a list of images. I want to pull out the very first image from the list of images via the jave list.get(index); I want to do something like "${a.slideShow.images.get(0)}";. The get() is a java method from the list object.
Any ideas?
Solution
In EL you can use the brace notation to access a List
element by index. Thus, the following should do:
arr[${status.index}] = "${a.slideShow.images[0]}";
This will behind the scenes do exactly as you proposed: a.getSlideShow().getImages().get(0)
.
That said, you normally declare JS arrays like follows:
var arr = [];
The new
keyword is considered discouraged in JS.
OTHER TIPS
As those who commented on your question suggest, this is a common misunderstanding. By the time your JavaScript executes (in the browser), Java and JSP and JSTL are no longer available. The JSTL/JSP execute at the server to create source/HTML that is then sent to the client.
View source on your page - it might shed some light. You should not see the JSP/JSTL you include above.