Previous
Chapter 2
Input Validation with Action Forms
Input validation is an important task in Web application development. It includes checking if there is a value in a mandatory field, whether a date or a number was entered in the correct format, etc. Struts action forms make input validation easier and with them you can easily display error messages and redisplay a form’s previous field values without the need to resort to Java code.
This chapter focuses on how action forms help input validation in Struts. It first explains how the action form works, and then presents an example that demonstrates how powerful action forms can be. This chapter also introduces the HTML Tag Library for working with action forms, even though further details are discussed in Chapter 3. Furthermore, you can also find the discussion of error handling when working with action forms. In this respect, this chapter serves as an introduction to other topics of discussions: Struts validation in Chapter 4 and the Validator plug-in in Chapter 5.