How to refresh the content of a JSP?

Question

I have a jsp page , on a button click I want to fetch values from bean and do some action on the basis of that data.

(This button is not posting or getting anything but only makes some UI level changes.)

Conditions: Page must not be refreshed, only a certain part of page is refreshed and that too only when that button is pressed.

I have

 <wcbase:useBean id="beanUtil" classname="UtilBean">
        <c:set property="studentId" value="${WCParam.studentId}" target="${beanUtil}" />
        </wcbase:useBean>
            <c:set property="classId" value="${class.uniqueID}" target="${beanUtil}" />
            <c:set var="listOfStudents" value="${beanUtil.StudentIdsforTransfer}" />
                                
            <c:if test="${not empty listOfStudents}">
                <script>var listOfStudents= true; </script>
            </c:if>
            <c:if test="${empty listOfStudents}">
                <script>var listOfStudents = false;</script>
                </c:if>

I need to call this whole section on a button click

how to do it?

All the help would really be appreciated.

Note: I have tried to put this code in div and then tried to refresh that div on button click but it didnt work.

something like :

Put in js

  $('#studentDiv').load(document.URL +  '#studentDiv');

Put in jsp.

 <div id="studentDiv">

 <wcbase:useBean id="beanUtil" classname="UtilBean">
        <c:set property="studentId" value="${WCParam.studentId}" target="${beanUtil}" />
        </wcbase:useBean>
            <c:set property="classId" value="${class.uniqueID}" target="${beanUtil}" />
            <c:set var="listOfStudents" value="${beanUtil.StudentIdsforTransfer}" />
                                
            <c:if test="${not empty listOfStudents}">
                <script>var listOfStudents= true; </script>
            </c:if>
            <c:if test="${empty listOfStudents}">
                <script>var listOfStudents = false;</script>
                </c:if>
</div>

This code refreshed the page but inserted the whole page again with in the main page and stayed in process.

You can't (with JSP) as JohnRose said that should be done with ajax, you have to send a async request to your server get the data (for example a json) and modify the html manually. — luisZavaleta, May 28 '14 at 06:49

Java Enthusiast · Answer 1 · 2014-05-28T06:43:10.537

You can refresh the JSP page with the help of the following statement

TimeUnit.SECONDS.sleep(5);

It reloads the page after 5 seconds..You can change it according to your need

I have used the above line in my code as follows..have a look..it might help you

  <form action="haryana.jsp" method="get" class="values">
            <table cellspacing="4" cellpadding="4">
                <tr>
                    <td>Select Industry</td>
                    <td><select name="sta" class="dropdown">
                            <option>Industry</option>
                            <option>Cotton</option>
                            <option>Sugar</option>
                            </select></td>
                </tr>
                <tr>
                    <td>Select Category </td>
                    <td><select name="ind" class="dropdown">
                            <option>Category</option>
                            <option>Area</option>
                            <option>Production</option>
                            <option>Yield</option>
                        </select></td>
                </tr>
                <tr class="blank_row">

                </tr>
                <tr>
                    <td><input type="submit" value="Submit" style="margin-top: 10px;" name="bt" class="btn btn-primary btn1"/></td>
                </tr>
            </table>
            <%
                if (request.getParameter("bt") != null) 
                {
                    categoryDataset = new DefaultCategoryDataset();
                    try 
                    {
                        st=request.getParameter("sta").toLowerCase();
                        indus = request.getParameter("ind").toLowerCase();
                        String qry = "select year,"+indus+" from "+st+" where year between '2007-08' and '2013-14'  and state='Haryana'";
                        utility ut = new utility();
                        ResultSet rs = ut.DQL(qry);
                        while (rs.next()) 
                        {
                            a=Float.parseFloat(rs.getString(""+indus));
                            b=Math.round(a);
                            categoryDataset.setValue(b, "" + st, "" + rs.getString("year"));
                            data1.setValue("" + rs.getString("year"), b);
                        }
                        JFreeChart chart1 = ChartFactory.createPieChart(""+indus,   data1, true, true, false);
final ChartRenderingInfo info1 = new ChartRenderingInfo(new StandardEntityCollection());
                        final File file2 = new File("F:/JavaAptech/Netbeans 74 applications/MinorProj/web/" + "har1" + st + indus + ".png");
                        img1 = "har1" + st + indus + ".png";
                        ChartUtilities.saveChartAsPNG(file2, chart1, 450, 300, info1);
                        chart1.setBorderVisible(true);
                    } 
                    catch (Exception e) 
                    {
                       // out.println(e);
                        %>
                        <script>
                            alert("Invalid Input/Data Unavailable");
                        </script>
                        <%
                    }%>
        </form>
    </div>
  <div style="float:left;width:70%;height:380px;">
     <%TimeUnit.SECONDS.sleep(5); %>
     <img style="margin-left: 15px;margin-top:3px;width:450px;height: 350px;"  src=     <%=img1%> USEMAP="#chart1"/>

</div>
    <%
         }
    %>

It will not refresh whole page..you can place it inside the div tag which you want to refresh and it will refresh only that part instead of whole page..try using it, u will understand what I am trying to say — Java Enthusiast, May 28 '14 at 06:11
actually I understand what you are saying but that div too must not be refreshed unless some action is performed. — Just_another_developer, May 28 '14 at 06:13
Is your div tag displaying after button click or its already there on the page when the page loads ? — Java Enthusiast, May 28 '14 at 06:16
It is already there. nad I am not saying that it must be div .... I just want to call the bean method on button click (like I mentioned in my post) whatever method need I apply. — Just_another_developer, May 28 '14 at 06:17
You can put the above statement in the part which is executing after the button click..it will show loading bar in top and your content will be loaded without refreshing the page — Java Enthusiast, May 28 '14 at 06:23
but on button click javascript is executed and I have no idea if we can initialize bean and use bean methods in Javascript... If it can be done kindly guide me how t do it. — Just_another_developer, May 28 '14 at 06:28
I have posted my code where i used that reloading page line..you can have a look at it and use accordingly in your code — Java Enthusiast, May 28 '14 at 06:43

score 0 · Answer 2 · edited May 23 '17 at 12:27

0

My suggestion is call ajax where your content to be refreshed. In "test.html" write the code to get values from your bean. Sample code

$.ajax({
  url: "test.html",
  context: document.body
}).done(function() {
  $( this ).addClass( "done" );
});

I give reference

Calling a backingBean method from javascript

how to call backing bean method from java script

How to call managed bean methods with parameters via JavaScript

Calling Managed Bean Method From JavaScript

edited May 23 '17 at 12:27

Community

1
1

answered May 28 '14 at 07:00

JohnRose

409
5
10

Would you please tell me how to call a method of a bean in javaScript/jQuery? – Just_another_developer May 28 '14 at 12:37

How to refresh the content of a JSP?

2 Answers2