EL Implicit Object pageContext

 pageContext   

     

Introduction:

1.  This is the only one EL implicit object which matches with Jsp implicit objects.

2.  By using this implicit object we can bring all other implicit objects into EL and accessing servlet and JSP properties, such as a request's protocol or server port, or the major and minor versions of the servlet API your container supports.

3.  You can find out that information and much more with the pageContext implicit object, which gives you access to the request, response, session, and application (also known as the servlet context).

4.  Useful properties for the pageContext implicit object are listed in Table 2.6.

Property	Type	Description
request	ServletRequest	The current request
response	ServletResponse	The current response
servletConfig	ServletConfig	The servlet configuration
servletContext	ServletContext	The servlet context
session	HttpSession	The current session

Ex: 1.${pageContext.request.method}

       2.${pageContext.session.id}

     

EL Implicit Object initParam

initParam

     

By using this implicit object we can access context initialization parameters.

ExpressionLanguage	Jsp  code
initParam.user	application.getInitParameter ( “user”)

Ex: ${initParam.user}   Output : scott

        ${initParam.pwd}   Output:Blank space.

Add this piece of code in web.xml

<context-param>           <param-name>user</param-name>           <param-value>chamu0001</param-value> </context-param> <context-param>           <param-name>password</param-name>           <param-value>myjavahub</param-value> </context-param>

 test.jsp

<%@ page isELIgnored="false" %> <% Cookie cookie = new Cookie ("username","chamu"); cookie.setMaxAge(60 * 60); response.addCookie(cookie); %> <table border= 2> <tr><td><h2>initParam.user</h2></td> <td><h2>${initParam.user}</h2></td></tr> <tr><td><h2>initParam.password</h2></td> <td><h2>${initParam.password}</h2></td></tr> </table>

Output:  http://localhost:8080/Scwcd_jsp/test.jsp

             

EL Implicit Object cookie

Cookie

                                                          

We can use this implicit object to retrieve cookies associated with the request.

Example :${cookie.JSESSIONID}

                 ${cookie.JSESSIONID.name}

                 ${cooke.JSESSIONID.value}

test.jsp

<%@ page isELIgnored="false" %> <% Cookie cookie = new Cookie ("username","chamu"); cookie.setMaxAge(60 * 60); response.addCookie(cookie); %> <table border= 2> <tr><td><h2>${cookie.username.name}</h2></td> <td><h2>${cookie.username.value}</h2></td></tr> <tr><td><h2>${cookie.JSESSIONID.name}</h2></td> <td><h2>${cookie.JSESSIONID.value}</h2></td></tr> </table>

First Request:

 Second Request: 



      

EL Implicit Object header & headerValues

                   header & headerValues      

                                  

                                                            

The header and headerValues objects are used to retrieve the header values normally available through the request.getHeader and request.getHeaders methods.

Ex: To access a header named user-agent, use the expression${header.user-agent} or ${header["user-agent"]}.

${header.accept}

${headerValues.accept[0]}

test.jsp

<%@ page isELIgnored="false" %> <table border = 2> <tr><td>header.cookie :</td><td>${header.cookie}</td></tr> <tr><td>header.connection</td><td>${header.connection}</td></tr> <tr><td>headerValues.host[0]</td><td>${headerValues.host[0]}</td></tr> <tr><td>headerValues.accept[0]</td><td>${headerValues.accept[0]}</td></tr> <tr><td>header.user-agent</td><td>${header.user-agent}</td></tr> </table>

Output: http://localhost:8080/Scwcd_jsp/test.jsp