Java Reference
In-Depth Information
C
HAPTER
11: H
ANDLING
W
EB
S
ERVICES
• Understanding Web Services
• Notable Public Web Services
• Using the Google Search API
• Creating Hybrid Bots
• Using the AXIS Framework
A bot is a program that accesses HTML and AJAX web sites that were designed for hu-
man visitors. This is often complex for the bot because the HTML is formatted for a human
to read. This is not the case with a web service. A web service is a web site that was designed
from the start to be accessed by other computers.
Web Services are an important aspect of HTTP programming. Web Services communi-
cate using HTTP. The data exchanged between a Web Service server and client is usually in
XML (Extensible Markup Language). This makes it very easy for a Java program to inter-
pret.
A program that accesses a web service is not typically called a bot. However, some bots
make use of Web Services to help them find other HTML sites to process. Such a bot is called
a hybrid bot. Hybrid bots will be discussed later in this chapter. Additionally, this chapter will
present one recipe that implements a hybrid bot.
Notable Public Web Services
Many different companies offer web services. Many major web sites offer some sort of
web service. If the web site you wish to work with offers a web service, this is the preferred
means of communicating with that site. Table 11.1 lists some of the most commonly used
Web Services.
