Examples of various applications of El Expressions in JSP _jsp programming

el Operator:

<% @page language= "java" contenttype= "text/html;charset=gb2312"%> <% @page import= "java.sql.*"%> <! DOCTYPE html>  

El Processing built-in objects:
"." and "[]" symbols are used to access data.

${applicationscope.user.username}

${applicationscope.user[0].username}

${applicationscope.user[" User-name "]}

Passing a value through a variable must use the []

${applicationscope.user["Data"]}

Storage-related built-in objects

 <!
    DOCTYPE html>  
 

Built-in objects related to input

<! DOCTYPE html>  

Cookie built-in objects

<! DOCTYPE html>
 
 

Header Built-in Object

<! DOCTYPE html>
 
 

Initparam built-in objects: Getting the environment variables set in the Web site

<% @page language= "java" contenttype= "text/html;charset=gb2312"%>
<! DOCTYPE html>
 
 

Pagecontex built-in objects
Use to get detailed information about a user request and page

<% @page language= "java" contenttype= "text/html;charset=gb2312"%> <!
    DOCTYPE html>  

el Accessor:
reads data in JavaBean using accessors

 package com.javaweb.ch08; import java.util.*;//A simple JavaBean example public class person{//n
  Ame Property private String name;
  Age attribute private int age;
  Sex property private String sex;
  Friends property Private ArrayList friends;
    The method public person (String name,int age,string sex) {this.name = name of the parameterless constructed method public person () {}//custom constructed;
    This.age = age;
  This.sex = sex;
  }//Gets the property value of name public String GetName () {return name;
  //Get the Age property value public int getage () {return age;
  //Get Sex property value public String Getsex () {return sex;
  //Sets the property of name, public void SetName (String name) {this.name = name;
  //Set Age's property value public void setage (int age) {this.age = age;
  }//Set sex property value public void Setsex (String sex) {this.sex = sex;
  }//Set friends value public void setfriends (ArrayList friends) {this.friends = friends;
  }//Get Friends Property value Public ArrayList getfriends () {return friends; }
}

<% @page language= "java" contenttype= "text/html;charset=gb2312%> <% @page import=" java.util.*, com.javaweb.ch08.* "%> <!
    DOCTYPE html>  

Using storage to read data in a map

 <% @page language= "java" contenttype= "text/html;charset=gb2312"%> <% @page Import= "java.util.*,com.javaweb.ch08.*"%> <! DOCTYPE html>  
 

Using memory to read data in an array

<% @page language= "java" contenttype= "text/html;charset=gb2312%> <%
@page import=" java.util.*, com.javaweb.ch08.* "%>
<! DOCTYPE html>
 
 

Complex applications of memory

<% @page language= "java" contenttype= "text/html;charset=gb2312%> <% @page import=" java.util.*, com.javaweb.ch08.* "%> <! DOCTYPE html>