JSP and Servlet tutorial for beginners - #2 - What is JSP?

I hope you have the necessary software [IDE and Servers] installed in your machine, if not, please take a look at this post to know how to install IDE and other stuffs and also do install them.

What is JSP?

• JSP stands for Java Server Pages and it was designed by Sun microsystem to compete with ASP and PHP in earlier 2000.
• Java Server Pages (JSP) technology is the Java platform technology for delivering DYNAMIC content to web clients in a portable, secure and well-defined way.
• JSP enables the developers to put java code into jsp, this makes the development process very simple and easy.
• Since JSP runs on Java Server, we can run it on any platform.
• JSP - Presentation layer which displays the actual output after the java statements in JSP are processed by the server container.

Intro to JSP tags:

• As we know that JSP is a scripting language which has its own tags to include Java content into it. Let’s have a brief look at the JSP tags.
• There are four types of JSP tags available, they are:
  • Directives:  In directive tag we can import packages, define error handling pages, handle session information of the JSP page.
  • Declarations: In declaration tag, we can provide the definition of  the functions and variables that are going to be used in the JSP.
  • Scriptlets: In this tag we can insert any amount of valid java code and these codes are placed in _jspService method by the JSP engine. [JSP engine converts JSP into Servlet]
  • Expresssions: We can use this tag to output any data on the generated page. These data are automatically converted to string and printed on the output stream[commonly browser].

Code snippet
Following are the sample code snippet:
>>Directives<<

<%@page contentType="text/html" import="java.util.Date" %>

>>Declarations<<

<%!String retString(){
return "Hello World";
}
%>

>>Scriptlets<<

<%out.print("Welcome to JSP");%>

>>Expressions<<

<%="Today's date: "+ new Date() %>

>>Comments<<

<%-- I am sample JSP comment--%>
<%-- JSP Engine will not process me!! :) --%>

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