Servlets & Servers

Q: I am currently running Microsoft s IIS server. I have the Java Virtual machine

installed on this system. What else will I need to run my servlet. Do need the Apache

web server instead? Will IIS support Java servlet?

Answer: You will need a Servlet Engine to run your servlets. 

You can use either Allaire s JRun (http://www.jrun.com) or Tomcat

(http://jakarta.apache.org).

Both of them work with IIS.

Madhusudhanan Challur

 Q: How can I avoid browser caching?

In an applet, I call the function showDocument to send a GET message to one of my

servlets, which sends me back a PDF file dynamically generated by this servlet.

My problem is : the browser (in this case IE) always sends me back a PDF file with

the same content.

Answer 1: There are a few possibilities to avoid this problem.

A simple workaround is to add a random number URL variable with the request, such

as "ranx" with a value of the milliseconds since midnight. This will make the request

unique and, hence, avoid browser caching.

by Duane Morse

Answer 2: There are two other response setHeader attributes you can set:

response.setHeader("pragma", "no cache");

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

response.setDateHeader("Expires", 0 )

Just in case.

Doug Schwartz

Answer 3: // for Answer 1 and 2 please go to yesterday s tip.

When you generate the PDF file, make sure you set the header to tell the browser

that the file will expire at a certain time. The browser should not cache the response

past the given time. The Java code looks something like

this:

import java.text.SimpleDateFormat;

import java.util.Date;

SimpleDateFormat dateFormat

= new SimpleDateFormat("EEE, dd MMM yyyy   HH:mm:ss z");

response.setHeader("Expires", dateFormat.format(new Date()));

The format of the date is very particular.

Scott Gartner

 Q: Wich free software can I use to debug Servlets?

Answer: What you need to do is use Jakarta Tomcat to run your servlets. Then, bring

in all the tomcat jars into your "required libraries".

Then set up your "project run" to actually run the Tomcat class. If you run it in debug

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