With Resin, servlets can use Java Bean-style configuration. A "Java Bean" is just a Java class that follows a simple set of rules. Each configuration parameter foo has a corresponding setter method setFoo with a single argument for the value. Resin can look at the class using Java's reflection and find the setFoo method. Because Resin can find the bean-style setters from looking at the class, it can configure those setters in a configuration file like the web.xml.

The following HelloServlet servlet is a trivial bean-style servlet. Instead of hardcoding the "Hello, world" string, it lets the web.xml configure the string as greeting. To make that work, HelloWorld adds a bean-style setGreeting(String) jmethod. package test; import java.io.*; import javax.servlet.http.*; import javax.servlet.*; public class HelloServlet extends HttpServlet { private String _greeting = "Default"; public void setGreeting(String greeting) { _greeting = greeting; } public void doGet (HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { PrintWriter out = res.getWriter(); out.println(_greeting); out.close(); } }

The configuration sets the greeting property inside an tag. After Resin instantiates the servlet object, it looks at the configuration file for any <init> section. Resin then calls a setXXX method for each <xxx> tag in <init>. In this case, Resin will call setGreeting