Reloading JSP page when there is any update in the database

[Keerthi Chandhu]

Hi,

Can anyone please suggest me how to reload a JSP page when user updates any value in the database from the screen?

Actually when user changes any value in the JSP it is being updated in the database but it is not giving the updated value in the JSP until user manually Refresh the page.

Thank you.

[Bear Bibeault]

Sounds like the common caching issue. Please see the JSP FAQ on this issue.

[ujjwal soni]

Hi,

Try doing this.

<% response.setHeader("Cache-Control","no-cache");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", -1);
response.setHeader("Cache-Control","no-store"); //HTTP 1.1
%>


Hope it works

[Bauke Scholtz]

ujjwal soni wrote:
<% response.setHeader("Cache-Control","no-cache");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", -1);
response.setHeader("Cache-Control","no-store"); //HTTP 1.1
%>

1) Scriptlets always indicate a bad practice.
2) Code duplication is always a bad practice.
3) You're overriding the correct Cache-Control header with an incorrect one.

[ujjwal soni]

Hi,

Thanks for your suggestion...

Prevent caching of JSP output

Put following scriptlet at the beginning of the JSP to prevent output caching

   1.
      <%
   2.
      response.setHeader("Cache-Control","no-cache"); //HTTP 1.1
   3.
      response.setHeader("Pragma","no-cache"); //HTTP 1.0
   4.
      response.setDateHeader ("Expires", 0); //prevent caching at the proxy server
   5.
      %>

it is always good to set Pragma header too, in case HTTP 1.0 is used.
Prevent caching of Servlet output

   1.
              protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   2.
       
   3.
                      response.setHeader("Cache-Control","no-cache");
   4.
                      response.setHeader("Pragma","no-cache");
   5.
                      response.setDateHeader ("Expires", 0);
   6.
                     
   7.
              }

[Keerthi Chandhu]

Hi Ujjwal soni ,

Thank you so much for the reply.

I tried making cache control

response.setHeader("Cache-Control","no-cache"); 

but it is not updating with the updated value utill I click refresh manually.

Actually to decrease number of queries to database, I am passing database values as parameters to another jsp and while displaying I am getting those parameters using

request.getAttribute("value from database");

when I update this value, it is getting updated in database but it is not displaying the updated value until I click refresh manually.
Would appreciate your help.

Thank you,

[Bear Bibeault]

ujjwal soni wrote:Put following scriptlet at the beginning of the JSP to prevent output caching

As previously pointed out, scriptlets are a poor practice. This should either be done in the page controller, or better yet, in a filter.

[Bauke Scholtz]

ujjwal soni wrote:Hi,

Thanks for your suggestion...

You're good at Googling. Why don't you explain the topicstarter how to do it so that s/he can learn from it? Why don't you mention the source of this information?