Introduction

This guideline focuses on designing of JSPs. Additional guidance on JSPs, such as how to identify and model them, is provided by Guideline: JavaServer Page (JSP)s.

Session State

Session state data managed or used by a JSP should be documented in the design of the JSP. See Guideline: Designing State for J2EE Applications for guidance on session state.

Servlet Context

Any interactions with the Servlet context should be documented in the design of the JSP. Servlet context is data global to the application, and should be managed carefully. See Guideline: Designing State for J2EE Applications for additional discussion of this mechanism.

Granularity and Responsibility

You should minimize the amount of Java code in a JSP, to improve maintainability and reusability, and to reduce complexity so that presentation designers can deal with page design without having to deal with Java code.  Do this by using JavaBeans and custom tag libraries.

JSP provides specific tags for invoking JavaBeans. Custom tags provide a simpler tag-with-attributes interface for accessing JavaBeans.

Common control logic should be moved into servlets, and business logic should be moved into JavaBeans (or into EJBs).

Consider using JavaScript to perform simple validation of input data at the client, to avoid the network overhead of passing a request back to the server.