How to clear the web browser cache?

perry · 03-06-2008, 03:02 PM

I am doing an web application over https that needs to clear the web browser cache after the transaction is completed. It's a credit card application. Hence you should realize what it is that I need to do.

Does anyone here have any JSP, Java experience with servlets and Tomcat and can tell me what to look out for ? Is there something that I do with the request or response parameters in the servlet that will cause the browser not to cache any information. If so and it is obvious to you, please feel free to point it out to me, it'll be greatly appreciated.

Thanks

- Perry

ps.
Thanks again moderators! The application is being developed and deployed on Linux servers.

unSpawn · 03-06-2008, 06:20 PM

Quote:

Originally Posted by perry

Moderators Please Have Mercy on Me

Why? You haven't violated the LQ Rules (yet)? ;-p

Quote:

Originally Posted by perry

clear the web browser cache after the transaction is completed.

client side cache means client side action, period.

Quote:

Originally Posted by perry

Is there something that I do with the request or response parameters in the servlet that will cause the browser not to cache any information.

http://www.linuxquestions.org/questi...9/#post3017638 ?

perry · 03-08-2008, 02:30 PM

Quote:

Originally Posted by unSpawn

Why? You haven't violated the LQ Rules (yet)? ;-p

client side cache means client side action, period.

http://www.linuxquestions.org/questi...9/#post3017638 ?

i figured it out after but thanks! i knew i would find something on this board related to my problem, i almost always do

thanks again

- perry

unSpawn · 03-09-2008, 06:26 AM

Well, then post your fix.

perry · 03-10-2008, 12:43 PM

Quote:

Originally Posted by unSpawn

Well, then post your fix.

You place meta tags in your html file. Perferably in two locations;

Code:

<head>
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="-1">
</head>
<body>
...
</body>
<head>
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="-1">
</head>

It seems odd to have two <head> sections but thats what they say to do.

It doesn't clear out the cache as hoped but does clear off anything the user may have entered. Which is good enough for me at the moment.

Thanks

- Perry

perry · 03-10-2008, 01:12 PM

In a totally related story, I had to create my own self-signed certificate for development purposes. This I found off the apache website for tomcat. There I found out the hard way all about the keypass= option (if you screwed up with the password you have to specify your password using keypass="yourpassword" in the connector under server.xml).

Code:

$JAVA_HOME/bin/keytool -genkey -alias tomcat -keyalg RSA

That was the easy part. Realizing that my .keystore file was located under My Documents (in Windows) was another.

It was here that I soon faced a problem. That is, how to do a form post. The browsers I was using could interface with localhost:8443 sure enough, however when I tried to access it with a Java program to do a form post, I ran into a SSLSecurityException. It seems there is no pop up windows in the world of stand alone Java as opposed to the option the browsers give you.

To properly deal with this problem, I was pleased to find out that I simply had to export my self-signed keystore:

Code:

keytool -export -alias tomcat -file tomcat.cer

Then I imported it into my JVM (first I had to check to make sure I was using the correct one as I have four different installations of Java on my machine):

Code:

keytool -keystore \java\jdk1.5.0_14\jre\lib\security\cacerts -import -alias tomcat -file tomcat.cer -trustcacerts

When prompted, use the password "changeit".

I honestly didn't think that I would have found a solution today, but I did. Just had to come here and post it.

Have you had your Java Today?

- Perry