Communicator e3000 MPE/iX Release 6.5 Express 2 (Software Release C.65.02) (30216-90322)

42 Chapter3

Technical Articles

Java Servlets for MPE/iX

Using Java Servlets

Writing Java Servlets

Java servlets on MPE follow the same rules and conventions as Java programs on MPE.

Any HP e3000 editor can be used to create a servlet ﬁle but, like Java programs, Java

servlets must be in bytestream format. Servlets created with vi or using Samba from a PC

will always be in bytestream format. Servlet ﬁles created using traditional HP e3000

editors such as EDIT/3000 and HP EDIT must be converted to bytestream using the tobyte

utility. For information on tobyte, execute "man tobyte" in the POSIX shell to invoke the

POSIX help facility.

The naming conventions for Java servlets follow those of Java programs:

• The name should be followed by the extension .java.

• The name is case-sensitive. While not a requirement, it is conventional to use mixed

case names with an initial capital and with additional capitals used if the class name

contains more than one word (for example, HelloWorld.java).

Java Servlet Class Deﬁnitions and Documentation

The jsdk.jar servlet classes in the JSDK2.0 are required for proper servlet execution

whether you write your own servlets or get them from another source. The jsdk.jar ﬁle

contains the javax.servlet and javax.servlet.http packages. To view the list of classes in

the jsdk.jar ﬁle, use the Java Archive Utility:

shell/iX>/usr/local/java/latest/bin/jar tvf /APACHE/SECURE/lib/jsdk.jar

shell/iX> /usr/local/java/latest/bin/jar tvf /APACHE/PUB/lib/jsdk.jar

For servlet API documentation and examples, use the following URL on your own server:

http://yourhost.com/JSDK2.0/doc/apidoc.

An Example Servlet

Servlets can be written to call any of the Java APIs available to Java applications.

Servlets use the Java standard extension classes in the packages javax.servlet (the basic

Servlet framework) and javax.servlet.http (extensions of the servlet framework for servlets

that answer HTTP requests) that are in the jsdk.jar ﬁle. Since servlets are written in Java

and follow a standard framework, they are portable between operating systems.

Here is an example of a simple servlet.

File: HelloWorld.java

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

/**

* This is a simple example of an HTTP Servlet. It responds to the GET