Question of the Week presents answers to key questions posed by the developer community. The intent is to pass this important, but not always easy-to-find, information on to Java^TM Developer Connection^SM (JDC) members. The questions are selected from the JDC Forums generally because: they are frequently asked, they are significant or timely, or the answers are not easily accessible.

Question of the Week Archive

Topic:   Servlet Configuration Questions

Questions:  

Servlet newbie looking for setup help (WinNT,JDK^TM 1.1.8,JSWDK^TM 1.0.1). I have two questions:

1. How do the servlet docBase and mapping properties work with the form ACTION tag to resolve the servlet's location?

The examples run fine, and if I create a servlet and put it into the examples directory with the other servlets, that runs fine, too. What I'm trying to do is something similar to the way CGI works. I want to place my servlets in a particular directory, and have them accessible via an action tag like ACTION=/old?u=http%3A%2F%2Fdeveloper.java.sun.com%2Fdeveloper%2Fqow%2Farchive%2F66%2F%26quot%3B%2Fservlet%2FmyServlet%26quot&y=1999 or at the worst ACTION=/old?u=http%3A%2F%2Fdeveloper.java.sun.com%2Fdeveloper%2Fqow%2Farchive%2F66%2F%26quot%3Bhttp%3A%2FmyServer%3A8080%2Fservlet%2FmyServlet%26quot%3B.&y=1999 If it makes a difference, I'm currently only using servlets to process form data, NOT to generate the form HTML like the examples do.

2. We run behind a firewall. Is there any way to have the servlets run without opening another port (such as 8080) to the world?

Answer:

1. If I understand your question properly, when you start servletrunner, you use the -d flag to state where the servlet lives and the -r flag to state where the document root is (that is, where to look for any files such as HTML templates) An example: bin\servletrunner -d examples\ -r examples\templates\

So, in your example, servletrunner if started as above would look for file examples\myServlet.class.

2. If using servlets for real, you would not use servletrunner. You would use something like WebSphere or Jrun that attaches itself to a WebServer. Requests come through on port 80 like any other HTTP requests but the Web Server identifies these as servlet requests and passes them to the Application Server to execute the servlet. The servlet builds the response and sends it to App Server which sends to Web Server and responds to Browser on port 80 again.

If you really need to use servletrunner, I know of no other way than to open know of no other way than to open another port.

Many thanks to JDC member astorer for contributing to this answer.

I get an exception NoClassDefFoundError when I try to run a java application over the network on a Windows 98 machine. But the same application runs perfectly over the network on a Windows NT workstation. Classpath for both 98 and NT workstation are the same. Any clues?
email to mehul_mehta@yahoo.com
Thanks
- Mehul Mehta

Mon Dec 06 01:42:11 PST 1999
[Member not logged in]

I have been wondering how could solve my problem before I read this anwser. I did exactly as the answer suggested to run "servletrun -d myServer". It was fine to get file running in myServer/myClass.class. The problem was the server could not find class files in a sub-directory of myServer. For example, if a file is in /myServer/subDir/myClass.class when it run http://homeHost:8080/servlet/myServer/subDir/myClass, the server indicated an error "Can't find subDir". Am I missing something here or simple the JSDK cannot run multiple directories under myServer?

(BTW, I run APACHE web server, but I don't think it is related)

Thank you.

Mon Dec 06 05:00:06 PST 1999
[Member not logged in]

the above comments seem applicable to the servletrunner not jswdk1.01

1) Java^TM Server Web Development Kit(JSWDK 1.01 implements web applications as defined in the servlet 2.2 API.

"A web application is a collection of resources that is mapped to a specific Uniform Resource Identifier (URI) prefix. These resources may include JSP pages, Servlets, HTML files, and images."

This is much more flexible, but also more complicated than the older system where all servlets went in the servlets directory. See the FAQ.html included with JSWDK1.01 for information on setting up web applications. See the Java Servlet API Specification 2.2 for more info.

2) The JSWDK is configured using the file webserver.xml (in the root directory) This file is self documenting. to change the port number change the line (near the bottom of the file) from port NMTOKEN "8080" to port NMTOKEN "80"

In my experience the JSWDK is very robust.

Mon Dec 06 06:51:35 PST 1999
[Member not logged in]

I downloaded the JSWDK so I could write and test servlets but it doesn't contain the jsdk2.0 or the jsdk.jar, Don't I need these thing to wwrite and test servlets? And where do I get them and how do I configure them?
Thank you for your time

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