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Introduction

Once you've developed a servlet with JBuilder, Visual Cafe, the Java JDK, or other development tools, you'll want to test the servlet. You can test it by plugging it right into your servlet-compatible web server, or you can take another approach -- testing it first with the servletrunner that comes with the Java Servlet Development Kit (JSDK).

In this article, we'll show you how to test simple Java servlets with the servletrunner.
 

Five questions about the servletrunner

1. What's a servletrunner?

The servletrunner is a small program that let's you test your Java servlets before deploying them to a web server.

Here's what the JSDK 2.0 documentation says about the servletrunner:

I like to think of the servletrunner as a mini web server that just runs Java servlets. The basic idea is that you can (1) create and then (2) test your Java servlets before adding the servlet to your Java web server environment. This is a useful debugging/testing idea, especially when you first begin working with servlets.

The servletrunner is located in the bin directory of the JSDK. As an example, I've installed the JSDK in a directory named C:\JSDK2.0 on my Windows PC, so the servletrunner is located in C:\JSDK2.0\BIN.
 

You can start the servletrunner in a variety of ways, but here's how I do it:
 
1. Create the servlet you want to deploy to your web server.
2. Copy the servlet to the C:\JAVA\JSDK2.0 directory.
3. Open a DOS window (Unix users: open a terminal/console window or telnet session). Use the cd command to move to the C:\JAVA\JSDK2.0 directory.
4. On a Windows PC, I start the servletrunner by running a small batch file I created for this purpose (see Listing 1).
5. Open Netscape (or another browser).
6. In Netscape, I enter the URL for the servlet to be tested. As an example, if the servlet is named myservlet, the URL will be "http://localhost:8080/servlet/myservlet".  (Note that the servletrunner listens on port 8080 by default.)
7. At this time, the output of your servlet should appear in your browser.

Note that if you have a more complicated Java servlet that requires the passing of parameters to the servlet, you'll have a few more steps to follow before starting the servletrunner.
 

REM REM  SRUNNER.BAT REM  ----------- REM REM  PURPOSE:  Run the JSDK 'servletrunner' REM REM  JDK installed in C:\JAVA\JDK1.1.5 REM  JSDK installed in C:\JAVA\JSDK2.0 set PATH=C:\WINDOWS;C:\WINDOWS\COMMAND;C:\JAVA\JDK1.1.5\BIN;C:\JAVA\JSDK2.0\BIN  set CLASSPATH=C:\JAVA\JSDK2.0\LIB\JSDK.JAR;C:\JAVA\JDK1.1.5\LIB\CLASSES.ZIP bin\servletrunner -d .

 

Listing 1:	This is the DOS batch file that I use to start the servletrunner. Because I use several different IDE's, I use this file to overwrite my PATH and CLASSPATH variables before starting the servletrunner.

 

It goes without saying that the first step is to read the documentation that comes with the JSDK.

As a next level of support, the servletrunner also includes a useful -help switch that briefly lists the command-line options. Here's what it looks like when you invoke it in a DOS window:
 

 C:\JAVA\JSDK2.0>  bin/servletrunner -help

Usage: servletrunner [options]
Options:
  -p port     the port number to listen on
  -b backlog  the listen backlog
  -m max      maximum number of connection handlers
  -t timeout  connection timeout in milliseconds
  -d dir      servlet directory
  -r root     document root directory
  -s filename servlet property file name
  -v          verbose output

 

To see the default values of these options, start the servletrunner with the -v switch. This has the side effect of starting the servletrunner, but it's easy to stop. Here's some sample output:
 

C:\JAVA\JSDK2.0> bin/servletrunner -v

Server settings:
  port = 8080
  backlog = 50
  max handlers = 100
  timeout = 5000
  servlet dir = .\examples
  document dir = .\examples
  servlet propfile = .\examples\servlet.properties

 

To stop the servletrunner in a DOS window, just type <CTRL>C. On a Unix system, just use your interrupt key (which may also be <CTRL>C). You'll be returned to your DOS (or Unix) prompt.

In a related servlet article, we showed you how to create a simple "Hello, world" servlet using JBuilder 2. Let's quickly walk through the steps that are required to test that Java servlet in the servletrunner.

1. Create the servlet. We performed this step in the JBuilder article.
2. Copy the servlet to the C:\JAVA\JSDK2.0 directory. On my system, the compiled JBHelloWorldServlet.class file is located in my C:\Apps\Win95\Inprise\JBuilder2\Projects directory, so I just copy it using the Windows Explorer.
3. Open a DOS window. Use the cd command to move to the C:\JAVA\JSDK2.0 directory.
4. Start the servletrunner by running the srunner.bat program.
5. Open Netscape (or another browser).
6. Enter the URL for the servlet to be tested. In this case, the servlet is named JBHelloWorldServlet, so the URL is "http://localhost:8080/servlet/JBHelloWorldServlet".
7. If everything worked as planned, the output of the servlet should appear in your browser.

Summary

The servletrunner that's supplied with the JSDK is a useful utility for testing and debugging Java servlets before you deploy them to your web server. This article answers basic questions about the servletrunner, and provides a step-by-step description of how to test a simple "Hello, world" servlet.  In a future article, we'll discuss the additional steps that may be required to test your more complicated Java servlets.

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