jsp page is cached, can not change it, tomcat

Question

Hallo,

I have a java server, when I change somethin within the JSP code, and I call the page again from the browser, my changes are not shown, the server returns the old JSP.

Do you have any idea why?

Answer 1

You can try doing 2 things:

Set <context-param> tag in web.xml

<context-param>
  <param-name>weblogic.jsp.pageCheckSeconds</param-name>
  <param-value>0</param-value>
</context-param>

In you Jsp page at the top:

<%
response.setHeader("Cache-Control","no-cache"); //HTTP 1.1
response.setHeader("Pragma","no-cache"); //HTTP 1.0
response.setDateHeader ("Expires", 0);
%>

Answer 2

The Jasper How-to tells that in conf/web.xml, for your org.apache.jasper.servlet.JspServlet you need:

• development - Is Jasper used in development mode? If true, the frequency at which JSPs are checked for modification may be specified via the modificationTestInterval parameter.true or false, default true.
• checkInterval - If development is false and checkInterval is greater than zero, background compiles are enabled. checkInterval is the time in seconds between checks to see if a JSP page (and its dependent files) needs to be recompiled. Default 0 seconds.

The <Context> element has the following properties:

• reloadable - set to true if you want hot-deployment of classes and libs in addition to jsp files
• antiResourceLocking - should be false

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All the above was about the server. Client-side caching is another reason why you may not see newer version of pages. Simply hitting CTRL+R / CTRL + F5 often suffices.

Deciding your cache strategy is something different, and a different topic - what resources would you tell the browser to cache, and for how long. Preferably you should put the cache headers - Expires and Cache-Control (and Pragma) in a common location in your application, where you can change it quickly.