Java variable not updating inside Javascript's setinterval

Question

Hi I am currently doing a web application where my Java code will constantly fetch data from a database and update its own static variable. I can confirm that the variable is being updated constantly when I output it in the console, however when I want to use this variable inside my Javascript function (which is inside my .jsp code), it always takes the initial value and never gets updated despite being inside a SetInterval function.

The following is the Javascript segment where I access the Java static variable.

function moveMarker(map,marker){

    setInterval( function(){  
        document.write(<%=DbManager.latitude%>);
    },5000);
}

The DbManager.latitude variable is always in it's default value despite being changed consistently when the web app is running. I look forward to any answers I can get to fix this issue, or perhaps alternatives to what I'm trying to achieve.

Answer 1

Better you can goahead with AJAX for this.

<script type="text/javascript">

    $(document).ready(function() {
        setInterval(ajaxCall, 5000); // 5 MS
    });     

    function ajaxCall() {
        $.ajax({
            type: "POST",
            url: "/getUpdate/" ,
            success: function(result) {
                document.write(result);
            }
          }
    });
</script>

Call your servlet/controller from AJAX and get the updated value

@Controller
@RequestMapping(value = "clause")
public class ClauseController {

  @RequestMapping(value="getUpdate") 
  @ResponseBody
  public String selectClause(ModelMap model) {
  DbManager dbManager = DAO.getDbManager;     
    return "dbManager.latitude";
  }
}