Let's create a simple JavaBean that works with a JSP and a servlet. We will make:
1. a main.html that takes a
String parameter and forwards it to
2. a mainController.jsp that instantiates a
JavaBean and populates it with the String parameter, then forwards it to a servlet
3. a JavaBean called InputBean that has a property called "input"
4. an OutputServlet that takes the property from InputBean and displays it on the browser.
For main.html we have:
Let's suppose the Tomcat4 install directory is catalina. We'll put this html in the app root, C:\catalina\webapps\myContext.
For the JSP we have:
For more information on JSP tags, refer to the Sun
link. Basically, since I will create the bean inside a package I will import it using the page directive, instantiate it with useBean, populate its "input" property with setProperty, and then finally forward it to the OutputServlet with servlet URL "/output". We'll also put this JSP in the app root, C:\catalina\webapps\myContext.
For the JavaBean, go to C:\catalina\webapps\myContext\WEB-INF\classes and create a folder named beans. Inside beans, create a JavaBean named InputBean:
Note that the public no-args constructor, as well the private fields and public accessor methods are part of the JavaBean specs.
Finally, we create the OutputServlet:
Note that we instantiate the actual JavaBean, retrieve its property and then display it to the client browser. Of course, this servlet resides in C:\catalina\webapps\myContext\WEB-INF\classes
We must register this servlet since the JSP uses a servlet mapping to forward the request. We must make the following changes to the web.xml file:
Note that all the <servlet> elements precede the <servlet-mapping> elements.
