File Structures for Servlets

File Structures for Servlets
Fall 2006, David Matuszek

These are notes that I made for myself, while getting assorted servlets to work. I'm posting it for whatever value it might have.

Where there are numbered options, the numbers in each section must correspond.

Note: The http://192.168.1.152 links are not functional; they are links to actual servlets on my own hard drive, not to a public server.

Simple web page; no servlets or JSP
A simple servlet
JSP only
A packaged servlet that uses JSP
A servlet that gets parameters
A servlet that opens a dialog on the server (!)
A servlet that returns a jar file

Simple web page; no servlets or JSP
URL	http://192.168.1.152/Hello.html http://192.168.1.152/simple/Hello.html http://192.168.1.152/SimpleNonROOT/Hello.html
Description	Static web page; WEB-INF folder must be present
File structure	webapps ROOT Hello.html WEB-INF webapps ROOT simple Hello.html WEB-INF webapps SimpleNonROOT WEB-INF Hello.html
web.xml	none

A simple servlet
URL	http://192.168.1.152/ch1/Serv1
Description	Servlet that displays the current time.
File structure	webapps ch1 WEB-INF classes Ch1Servlet.class web.xml
package	none
servlet-class	Ch1Servlet
url-pattern	/Serv1

JSP only
URL	http://192.168.1.152/Hello.jsp
Description	JSP only page; WEB-INF folder must be present
File structure	webapps ROOT Hello.html WEB-INF
web.xml	none

A packaged servlet that uses JSP
URL	http://192.168.1.152/Beer-v1/form.html
Description	Beer HTML page calls BeerExpert to compute results.
File structure	webapps WEB-INF classes com example model BeerExpert.class web BeerSelect.class web.xml form.html result.jsp
package	com.example.model com.example.web
servlet-class	com.example.web.BeerSelect
url-pattern	/SelectBeer.do

A servlet that gets parameters
URL	http://192.168.1.152/TestInitParams/TestInitParams http://192.168.1.152/TestInitParams2
Description	Servlet reads parameters from web.xml file
File structure	webapps TestInitParams WEB-INF web.xml classes com example TestInitParams.class webapps TestInitParams2 WEB-INF web.xml classes TestInitParams2.class
package	com.example (none)
servlet-class	com.example.TestInitParams TestInitParams2
url-pattern	/TestInitParams /TestInitParams2

A servlet that opens a dialog on the server (!)
URL	http://192.168.1.152/SendText/SendText http://192.168.1.152/SendText/ (if final slash is omitted, servlet works, and the response page adds a slash to the URL) http://192.168.1.152/SendText (see below)
Description	Servlet opens an input dialog and sends the inputted text back in an HTML page. All newlines are lost, however. Observation: The URL is the path structure, skipping over WEB-INF/classes/. Hence, webapps/x/WEB-INF/classes/y/z/Code.class --> /x/y/z/Code
File structure	webapps SendText WEB-INF classes SendText.class [some additional classes] web.xml
package	none
servlet-class	SendText
url-pattern	/SendText / This is actually <url-pattern></url-pattern> -- worked yesterday, but no longer works.

A servlet that returns a jar file
URL	http://192.168.1.152/JarDownload/form.html
Description	HTML page has a link to http://192.168.1.152/JarDownload/FunWithPanels.jar
File structure	webapps JarDownload form.html SwingLayoutExamples.jar WEB-INF classes CodeReturn.class web.xml
package	none
servlet-class	CodeReturn
url-pattern	/FunWithPanels.jar

Things I think I've learned

You always need a WEB-INF folder, even if it's empty.

If the package declaration says
     package x.y.z;
then the file structure is
     webapps - projectName - WEB-INF - classes - x - y - z - MyCode.class
and the servlet-class is
     x.y.z.MyCode
and the url-pattern is
     /whatever
then we need the URL
     http://localhost/whatever/