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30

Chapter 2 First Servlets

and the JSP JAR file. On Windows NT or Windows 2000, you go to the Start

menu, select Settings, select Control Panel, select System, select Environment,

then enter the variable and value. On Unix (C shell), you set the 

CLASSPATH

variable by

setenv CLASSPATH /install_dir/servlets:$CLASSPATH

Put this in your 

.cshrc

 file to make it permanent. 

If your package were of the form 

name1.name2.name3

 rather than simply

name1

 as here, the 

CLASSPATH

 should still point to the top level servlet direc 

tory, that is, the directory containing 

name1

. 

A second way to compile classes that are in packages is to keep the source

code in a location distinct from the class files. First, you put your package direc 

tories in any location you find convenient. The 

CLASSPATH

 refers to this loca 

tion. Second, you use the 

 d

 option of 

javac

 to install the class files in the

directory the Web server expects. An example follows. Again, you will probably

want to set the 

CLASSPATH

 permanently rather than set it each time.

DOS> cd C:\MyServlets\coreservlets

DOS> set CLASSPATH=C:\MyServlets;%CLASSPATH%

DOS> javac  d C:\tomcat\webpages\WEB INF\classes HelloWWW2.java

Keeping the source code separate from the class files is the approach I use

for my own development. To complicate my life further, I have a number of

different 

CLASSPATH

 settings that I use for different projects, and typically

use JDK 1.2, not JDK 1.1 as the Java Web Server expects. So, on Windows I

find it convenient to automate the servlet compilation process with a batch

file 

servletc.bat

, as shown in Listing 2.5 (line breaks in the 

set CLASS 

PATH

 line inserted only for readability). I put this batch file in 

C:\Win 

dows\Command

 or somewhere else in the Windows 

PATH

. After this, to

compile the 

HelloWWW2

 servlet and install it with the Java Web Server, I

merely go to 

C:\MyServlets\coreservlets

 and do  

servletc

HelloWWW2.java

 . The source code archive at 

http://www.coreserv 

lets.com/

 contains variations of 

servletc.bat

 for the JSWDK and Tom 

cat. You can do something similar on Unix with a shell script. 

Invoking Servlets in Packages

To invoke a servlet that is in a package, use the URL 

http://host/servlet/packageName.ServletName

instead of 

http://host/servlet/ServletName

Thus, if the Web server is running on the local system, 

Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.

Servlet and JSP training courses by book's author: courses.coreservlets.com.