Objective : EL (Expression Language)
-It is a feature of JSP 2.0
-Objective of EL is evaluating and outputting values stored in standard objects

Benefits 
- Shortcut methods for accessing data stored in different scopes(page,request,session,application)
- Easy access to request parameters and headers
- Easy access of data from arrays and collections
- Easy access of data from Beans
- Easy access of data from standard locations like cookies, parameters
- Simple and useful set of operators
-  Empty values instead of error messages
- implicit type casting

Syntax of EL :
	${Expression}

Accessing data from Scopes (Page, Request, Session and Application)

Syntax:
	${Expression}

Examples : jsp\class7
1. ScopedVars.java calls ScopedVars.jsp
To execute
http://localhost:8082/servlet/coreservlets.ScopedVars






Acessing Data from Bean
Syntax:	${bean.property}

Example :
BeanProperties.java uses EmployeeBean.java, NameBean.java and CompanyBean.java
calls beanproperties.jsp

Accessing Data from Collections
Syntax (index) :	${var[<index>]}
Syntax (key) :	${var["<key>"]}

Example :

Collections.java calls Collections.jsp






Accessing Data from implicit objects (cookies, param)

Syntax : ${object.property}
Example : implicit-objects.jsp
param.<Name> OR param["<Name>"]
header.<Name> OR header["<Name>"]

Operators supported by EL

Arithmetical : +,-,*,/,%, mod,  div
Relational : > , < , >= , <= , != , == , eq , ne , lt, le , gt , ge
Logical : &&, and , ||, or , !, not
Empty :	empty param.test
Conditional : <cond> ? T-Part : F-Part

Example :
1. operators.jsp
2. Conditionals.java uses SalesBean.java calls conditionals.jsp















Java Server Tag Library (JSTL)



It is a collections of TAGS.
These Tag libraries can be inform of 
1. Custom Tag Library
2. Standard Tag Library

Custom Tag Library
- Each Tag is in the form of a file. 
- The name of the file is the name of tag
- Extension of this file is .tag
- Collection of .tag files are stored in a directory, this directory is called as the tag library
- This directory (tag library) should be present by any name within webapps\root\WEB-INF

To call Tag libraries within your jsp page, <%@ taglib %> directive is used:
<%@ taglib prefix="tags" tagdir="/WEB-INF/tags" %>

prefix : the prefix that should be used to refer to tags of this library
tagdir : the name and path of the tag library

To refer tags from this library
<prefix:tagName>...</prefix:tagName>

Example : jsp\class8
	1. hello.jsp uses helloWorld.tag
	2. panel.jsp uses panel.tag


















































































































