book

Python Cookbook

by Alex Martelli, David Ascher

July 2002

Intermediate to advanced

608 pages

15h 46m

English

O'Reilly Media, Inc.

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Content preview from Python Cookbook

Running a Servlet with Jython

Credit: Brian Zhou

Problem

You need to code a servlet using Jython.

Solution

Java (and Jython) is most often deployed server-side, and thus servlets are a typical way of deploying your code. Jython makes them easy to use:

import java, javax, sys

class hello(javax.servlet.http.HttpServlet):

    def doGet(self, request, response):
        response.setContentType("text/html")
        out = response.getOutputStream(  )
        print >>out, """<html>
<head><title>Hello World</title></head>
<body>Hello World from Jython Servlet at %s!
</body>
</html>
""" % (java.util.Date(  ),)
        out.close(  )
        return

Discussion

This is no worse than a typical JSP! (See http://jywiki.sourceforge.net/index.php?JythonServlet for setup instructions.) Compare this recipe to the equivalent Java code; with Python, you’re finished coding in the same time it takes to set up the framework in Java. Note that most of your setup work will be strictly related to Tomcat or whatever servlet container you use; the Jython-specific work is limited to copying jython.jar to the WEB-INF/lib subdirectory of your chosen servlet context and editing WEB-INF/web.xml to add <servlet> and <servlet-mapping> tags so that org.python.util.PyServlet serves the *.py <url-pattern>.

The key to this recipe (like most other Jython uses) is that your Jython scripts and modules can import and use Java packages and classes as if the latter were Python code or extensions. In other words, all of the Java libraries that you could use with Java code are ...