Chapter 6 Examples from Java Servlet
- 6-1: Hello World graphics
- 6-2: A chart comparing applets and oranges
- 6-3: Drawing over an image to mark it confidential
- 6-4: Combining images to form a graphical counter
- 6-5: An image effect converting an image to grayscale
- 6-9: Embedding SecondApplet
- 6-10: A generic applet viewer
- 6-11: Sending compressed content
- 6-12: Countdown to a rocket launch
Examples from other chapters:
- Example 6.1: Hello World graphics
- This servlet generates and returns a GIF image. The
graphic says "Hello World!"
- Example 6.2: A chart comparing applets and oranges
- This servlet creates a bar chart that compares apples to
oranges, with regard to their annual consumption. There's
little need for this chart to be dynamically generated, but
it lets us get the point across without too much code.
Picture in your mind's eye that the servlet is charting
up-to-the-minute stock values or the server's recent load.
- Example 6.3: Drawing over an image to mark it confidential
- This servlet writes "CONFIDENTIAL" over every image it
returns. The image name is passed to the servlet as extra
- Example 6.4: Combining images to form a graphical counter
- This servlet displays a hit count as a sequence of
individual number images combined into one large image.
- Example 6.5: An image effect converting an image to grayscale
- This servlet shows a servlet that converts an image to
grayscale before returning it. The servlet performs this
effect without ever actually creating an off-screen graphics
context. Instead, it creates the image using a special
- Example 6.9: Embedding SecondApplet
- This servlet embeds SecondApplet inside itself and sends
a picture of the applet to the client. It uses a modified
version of Jef Poskanzer's Acme.MainFrame class, available in
example code JAR. The fonts can
appear weird depending on the system fonts installed.
- Example 6.10: A generic applet viewer
- This servlet is a servlet capable of embedding and taking
a picture of any applet. It can accept as request parameter
the applet name, its width and height, and its parameters.
- Example 6.11: Sending compressed content
- This servlet is the ViewFile servlet from Chapter 4
rewritten to send compressed content whenever possible. An
end user cannot tell that the server sent compressed content
to the browser--except perhaps with reduced download times.
It's disabled because the servlet would happily serve any
files from this site.
- Try it (disabled for security)
- Example 6.12: Countdown to a rocket launch
- This servlet uses server push to display a countdown to a rocket
launch. It begins by sending a series of pages that count down
from 10 to 1. Every page replaces the previous page. When the
countdown reaches 0, the servlet sends a picture of a launch.
It uses the com.oreilly.servlet.MultipartResponse utility class
to manage the server push details. This example does not work
with Microsoft Internet Explorer.