[8.7] JSP pageContext implicit object

JSP pageContext implicit object

JSP pageContext object is an instance of javax.servlet.jsp.PageContext. This object is used to manipulate page, request, application and session attributes.

Example:

login.jsp
<html>
 <head>
  <title>login</title>
 </head>
 <body> 
  <form action="welcome.jsp">
   <input type="text" name="userName" />
   <input type="submit" value="login"/>
  </form>
 </body>
</html>
welcome.jsp
<html>
 <head>
  <title>pageContext implicit object example</title>
 </head>
 <body> 
     <%
  String userName = request.getParameter("userName");
  if(userName.equals("jai")){
    pageContext.setAttribute("userName",
                              userName, PageContext.SESSION_SCOPE);
    response.sendRedirect("home.jsp");  
  }else{
    out.print("Wrong username.");  
  }
 %>
 </body>
</html>
home.jsp
<html>
 <head>
  <title>home</title>
 </head>
 <body> 
 <h3>This is user home page.</h3>
 <%
 String userName = (String)pageContext.getAttribute("userName",
                                               PageContext.SESSION_SCOPE);
 out.print("Logged in user: " + userName);
 %>
 </body>
</html>
web.xml
<web-app>
 
  <welcome-file-list>
          <welcome-file>login.jsp</welcome-file>
  </welcome-file-list> 
 
</web-app>

Output:

Enter UserName: jai

Click on login button.