Java Server Pages Overview

Scripting Elements

The scripting elements in a JSP page comprise of four types :

1. Comments 2. Class level declarations 3. Expression 4. Scriptlets

Comments

Like other Java classes we can add comments in a JSP page. Comments are useful as it makes your code more understandable.

The syntax of JSP comment is as follows:

<%-- This is a JSP Comment --%>

Class Level Declarations

This feature allows us to add our own class level methods and variables which can be accessed by the scriptlets.

It's syntax is as follows :

<%! Declaration Statement %>

For example :

<%! String author = "Aman Kumar"; %>

Above code declares a class level variable named author with a value of "Aman Kumar".

Expression

It is a short hand for writing output directly to the output stream.

Its syntax is as follows:

<%= statement %>

The value of the Java statement is displayed to the user. e.g,

<%= new java.util.Date().toString() %>

Above code displays the current date and time to the user.

Scriptlets

Within scriptlets we can add whatever Java code we like. All this code will go inside the _jspService() method, so we cannot declare class level methods or variables within scriptlets

It's syntax is as follows :

<% statements %>

For example:

<% String name = "Aman Kumar"; out.println("My name is " + name); %>

Above code first declares a name variable with value of "Aman Kumar" and then displays it to the user screen.