Struts Kick Start: Building Applications

• By Kevin Bedell and James Turner
• Mar 7, 2003
• Sample Chapter is provided courtesy of Sams

This chapter is from the book
Struts Kick Start

In This Chapter

• Hello World! Application Requirements

• Applying the Model-View-Controller Pattern

• The View Component: The HTML Form and the Form Bean

• MessageResources and Application.properties Files

• The Struts Form Bean: HelloForm.java

• Data Validation and ActionErrors

• The Controller Component: HelloAction.java

• The Model Component (HelloModel.java)

• Passing Data to the View Using Attributes: Constants.java

• Tying It All Together: The struts-config.xml File

• Conclusions

This chapter provides a rapid introduction to Struts by building a complete—although basic—application from scratch. The goal of this chapter is to enable a competent developer to quickly grasp all the basics of how to build Struts applications.

The chapter continues the longstanding tradition of developing a first program in a new language that simply prints Hello World!. This enables developers to quickly grasp the fundamentals of how the program works without forcing them to think too much about the application requirements. To demonstrate some of the important features of Struts, however, the application built here will have a few additional features.

Development of a sample application will be covered including:

• Application requirements

• Using the Model-View-Controller pattern to design a solution using Struts

• The View component: The HTML form and the form bean

• MessageResources and Application.properties files

• The Struts form bean: HelloForm.java

• Data validation and using ActionErrors

• The Controller component: HelloAction.java

• The Model component: HelloModel.java

• Passing data to the View using attributes: Constants.java

• Tying it all together: struts-config.xml

Hello World! Application Requirements

The requirements of this application are very basic. They are as follows:

• Enable the user to enter a name to say Hello! to and output the string Hello <name>!.

• Don't let the user submit the entry form without entering a name. If he does, provide an error message to help him fill the form out correctly.

• To add more Controller functionality (and have a bit more fun), the application should not allow the user to say hello to people they're "not allowed" to talk to.

• To demonstrate Model components, the application should use a Model component to save the name entered for later.

This basic application provides a little bit of functionality in all three of the Model, View, and Controller components.