Input and Output
User input is a necessity in modern web pages. Most dynamic web sites generate pages based on user input. Unfortunately, users seldom enter information in exactly the format you need, so before you can use such input, you probably want to validate it.
And it’s not only the input format that’s important. Web browsers are also picky about the format of the HTML you send them. For instance, when you generate an HTML form with values taken from a database, a name such as O’Reilly can cause problems. The single quote character after the O can fool the browser into believing that it’s at the end of the string, so you end up with just an O in your form.
Using JavaBeans to Process Input
As we saw earlier, a bean is often used as a container for data, created by some server process, and used in a JSP page that displays the data. But a bean can also be used to capture user input. The captured data can then be processed by the bean itself or used as input to some other server component (e.g., a component that stores the data in a database or picks an appropriate banner ad to display). The nice thing about using a bean this way is that all information is in one bundle. Say you have a bean that can contain information about a person, and it captures the name, birth date, and email address as entered by the person on a web form. You can then pass this bean to another component, providing all the information about the user in one shot. Now, if you want to add more information about ...