Question

I have a JSP page which shows items included in an Array (Just a very simple list).
In the background the Array might change i.e. adds a new Item or remove one.

How can I auto refresh the page when the Array changes?

Answer 1

There are 2 ways that are most popular to perform such operation

• pool a method that would send 1 or 0 to see if you refresh the page or not
• keep asking for that data array and populate it through javascript

---

Option 1

• create a .jsp page and call it, for example, updateList.jsp
• add a single method that will check if there is more data to be filled and output 1 or 0 like: out.println(1)
• in your page, and using jQuery to simplify things

 $.get("updateList.jsp", function(data) {
    if(data !== null && data.length > 0 && data === 1) {
        // refresh this page
        document.location = document.location.href;
    }
 });

---

Option 2

• create a .jsp page and call it, for example, data.jsp
• add a single method that will output a JSON string containing all data you need to populate the list
• in your page, and using jQuery and JsRender to simplify things

 $.get("updateList.jsp", function(data) {
    if(data !== null && data.length > 0) {
        $("#my-list").html(
            $("#my-template").render(data);
        );
    }
 });

and in your HTML you will have:

<ul id="my-list"></ul>

<script id="my-template" type="text/x-jsrender">
    {{for items}}
      <li>{{:name}}</li>
    {{/for}}
</script>

assuming your JSON would be something like:

item: [
    { name: "Name A" },
    { name: "Name B" },
    { name: "Name C" },
]