EL運算符：
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@page import="java.sql.*" %>
<!DOCTYPE html>
<html>
<head>
<title>El算數運算符</title>
</head>
<body>
<table border=1>
<tr>
<td>算數運算符</td>
<td>結果</td>
</tr>
<tr>
<td>加法運算符\${1 + 1}</td>
<td>結果${1+1}</td>
</tr>
<tr>
<td>減法運算符\${1 - 1}</td>
<td>結果${1-1}</td>
</tr>
<tr>
<td>乘法運算符\${1 * 2}</td>
<td>結果${1 * 1}</td>
</tr>
<tr>
<td>除法運算符\${3 / 2}</td>
<td>結果${3 / 2}</td>
</tr>
<tr>
<td>求余運算符\${3 % 2}</td>
<td>結果${3 % 2}</td>
</tr>
</table>
<table border=1>
<tr>
<td>關系運算符</td>
<td>結果</td>
</tr>
<tr>
<td>等於運算符\${1 == 1}</td>
<td>結果${1==1}</td>
</tr>
<tr>
<td>不等於運算符\${1 != 1}</td>
<td>結果${1!=1}</td>
</tr>
<tr>
<td>小於運算符\${1 < 2}</td>
<td>結果${1 < 2}</td>
</tr>
<tr>
<td>大於運算符\${3 > 2}</td>
<td>結果${3 > 2}</td>
</tr>
<tr>
<td>小於等於運算符\${1 <= 2}</td>
<td>結果${1 <= 2}</td>
</tr>
<tr>
<td>大於等於運算符\${3 >= 2}</td>
<td>結果${3 >= 2}</td>
</tr>
</table>
<table border=1>
<tr>
<td>邏輯運算符</td>
<td>結果</td>
</tr>
<tr>
<td colspan="2">邏輯運算符&&</td>
</tr>
<tr>
<td>\${true && true}</td>
<td>結果${true && true}</td>
</tr>
<tr>
<td>\${true && false}</td>
<td>結果${true && false}</td>
</tr>
<tr>
<td>\${false && false}</td>
<td>結果${false && false}</td>
</tr>
<tr>
<td colspan="2">邏輯運算符||</td>
</tr>
<tr>
<td>\${true || true}</td>
<td>結果${true || true}</td>
</tr><tr>
<td>\${true || false}</td>
<td>結果${true || false}</td>
</tr><tr>
<td>\${false || false}</td>
<td>結果${false || false}</td>
</tr>
<tr>
<td colspan="2">邏輯運算符!</td>
</tr>
<tr>
<td>\${!true}</td>
<td>結果${!true}</td>
</tr><tr>
<td>\${!false}</td>
<td>結果${!false}</td>
</tr>
</table>
<table border=1>
<tr>
<td>條件運算符</td>
<td>結果</td>
</tr>
<tr>
<td>\${2>1?"Yes":"No"}</td>
<td>結果${2>1?"Yes":"No"}</td>
</tr>
<tr>
<td>\${2<1?"Yes":"No"}</td>
<td>結果${2<1?"Yes":"No"}</td>
</tr>
</table>
<table border=1>
<tr>
<td>驗證運算符</td>
<td>結果</td>
</tr>
<tr>
<td>\${empty param.username}</td>
<td>結果${empty param.username}</td>
</tr>
<tr>
<td>\${empty param.password}</td>
<td>結果${empty param.password}</td>
</tr>
</table>
<table border=1>
<tr>
<td>括號運算符及運算符的優先級</td>
<td>結果</td>
</tr>
</table>
</body>
</html>
EL處理內置對象：
“.”和"[]"符號是用來存取數據的
${applicationScope.user.username}
${applicationScope.user[0].username}
${applicationScope.user["user-name"]}
通過變量來傳值就必須使用[]
${applicationScope.user["data"]}
與存儲有關的內置對象
<!DOCTYPE html>
<html>
<head>
<title>與存儲有關的內置對象</title>
</head>
<body>
<%
//application范圍設置屬性name，值為application_name
application.setAttribute("name","application_name");
//session范圍設置屬性name，值為session_name
session.setAttribute("name","session_name");
//request范圍設置屬性name，值為request_name
request.setAttribute("name","request_name");
//page范圍設置屬性name，值為page_name
pageContext.setAttribute("name","page_name");
%>
<%--獲取page范圍內的name屬性--%>
page范圍內的那麼屬性的值為：${pageScope.name}<br />
<%--獲取request范圍內的name的屬性--%>
request范圍內的那麼屬性的值為：${requestScope.name}<br />
<%--獲取session范圍內的name的屬性--%>
session范圍內的那麼屬性的值為：${sessionScope.name}<br />
<%--獲取application范圍內的name屬性--%>
application范圍內的那麼屬性的值為：${applicationScope.name}<br />
</body>
</html>
與輸入有關的內置對象
<!DOCTYPE html>
<html>
<head>
<title>用戶表單</title>
</head>
<body>
<form action="UserDemo.jsp" method="post">
用戶名：<input type="text" name="username" /><br />
密碼：<input type="password" name="password" /><br />
姓名：<input type="text" name="name" /><br />
性別：<input type="radio" name="sex" value="男">男<input type="radio" name="sex" value="女">女<br />
愛好：<br />
<input type="checkbox" name="interest" value="打籃球">打籃球<br />
<input type="checkbox" name="interest" value="看書">看書<br />
<input type="checkbox" name="interest" value="旅行">旅行<br />
<input type="checkbox" name="interest" value="編程">編程<br />
<input type="submit" value="提交">
<input type="reset" value="重置">
</form>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<title>接收用戶參數</title>
</head>
<body>
<%
//設置頁面編碼格式
request.setCharacterEncoding("gb2312");
%>
<%--接收用戶參數--%>
用戶名：${<span >param</span>.username}<br />
密碼：${<span >param</span>.password}<br />
姓名：${<span >param</span>.name}<br />
性別：${<span >param</span>.sex}<br />
愛好：${<span >paramValues</span>.interest[0]}
${<span >paramValues</span>.interest[1]}
</body>
</html>
cookie內置對象
<!DOCTYPE html>
<html>
<head>
<title>設置cookie的值</title>
</head>
<body>
<%
//設置cookie的值
Cookie c = new Cookie("username","root");
//添加cookie到客戶端
response.addCookie(c);
%>
<a href="getCookieDemo.jsp">顯示cookie的值</a>
</body>
</html>
<span ><%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>取得cookie的值</title>
</head>
<body>
cookie中的username的值為：${cookie.username.value}
</body>
</html>
header內置對象
<!DOCTYPE html>
<html>
<head>
<title>取得header的值</title>
</head>
<body>
${header["host"]}<br />
${header["user-agent"]}<br />
</body>
</html>
initParam內置對象:獲取web站點中設置的環境變量
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>獲得環境參數</title>
</head>
<body>
username參數值：${initParam.username}<br />
</body>
</html>
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<context-param>
<param-name>username</param-name>
<param-value>Zhangdapeng</param-value>
</context-param>
</web-app>
pageContex內置對象
用來取得有關用戶請求和頁面的詳細信息
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>pageContext演示</title>
</head>
<body>
<table border="1">
<tr>
<td>取得請求的參數的字符串</td>
<td>${pageContext.request.queryString}</td>
</tr><tr>
<td>取得請求URL</td>
<td>${pageContext.request.requestURL}</td>
</tr><tr>
<td>取得web應用名稱</td>
<td>${pageContext.request.contextPath}</td>
</tr><tr>
<td>取得HTTP請求方式（POST/GET）</td>
<td>${pageContext.request.method}</td>
</tr><tr>
<td>取得使用的協議</td>
<td>${pageContext.request.protocol}</td>
</tr><tr>
<td>取得用戶IP地址</td>
<td>${pageContext.request.remoteAddr}</td>
</tr><tr>
<td>判斷session是否為新</td>
<td>${pageContext.session.new}</td>
</tr><tr>
<td>取得session的id</td>
<td>${pageContext.session.id}</td>
</tr>
</table>
</body>
</html>
EL存取器:
使用存取器讀取JavaBean中的數據
package com.javaweb.ch08;
import java.util.*;
//一個簡單的JavaBean示例
public class Person{
//name屬性
private String name;
//age屬性
private int age;
//sex屬性
private String sex;
//friends屬性
private ArrayList friends;
//無參構造方法
public Person(){
}
//自定義構造的方法
public Person(String name,int age,String sex){
this.name = name;
this.age = age;
this.sex = sex;
}
//獲取name的屬性值
public String getName(){
return name;
}
//獲取age屬性值
public int getAge(){
return age;
}
//獲取sex的屬性值
public String getSex(){
return sex;
}
//設置name的屬性
public void setName(String name){
this.name = name;
}
//設置age的屬性值
public void setAge(int age){
this.age = age;
}
//設置sex的屬性值
public void setSex(String sex){
this.sex = sex;
}
//設置friends的值
public void setFriends(ArrayList friends){
this.friends = friends;
}
//獲取friends的屬性值
public ArrayList getFriends(){
return friends;
}
}
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@page import="java.util.*,com.javaweb.ch08.*" %>
<!DOCTYPE html>
<html>
<head>
<title>設置JavaBean中的屬性</title>
</head>
<body>
<%
//實例化一個Person
Person person = new Person("zhangdapeng",24,"男");
//創建一個friends實例
ArrayList friends = new ArrayList();
//添加值
friends.add("wang wu");
friends.add("li si");
person.setFriends(friends);
//存儲在session范圍內
session.setAttribute("person",person);
%>
<a href="GetJavaBean.jsp">跳轉到GetJavaBean.jsp</a>
</body>
</html>
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>取得JavaBean中的屬性值</title>
</head>
<body>
姓名：${sessionScope.person.name}<br />
年齡：${sessionScope.person.age}<br />
性別：${sessionScope.person.sex}<br />
朋友：${sessionScope.person.friends[0]},${sessionScope.person.friends[1]}<br />
</body>
</html>
使用存儲器讀取Map中的數據
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@page import="java.util.*,com.javaweb.ch08.*" %>
<!DOCTYPE html>
<html>
<head>
<title>設置Map頁面</title>
</head>
<body>
<%
//新建一個HashMap
HashMap userInfo = new HashMap();
//在HashMap中設置值
userInfo.put("username","zhangdapeng");
userInfo.put("password","zhnagda123");
//將值存儲到session范圍中
session.setAttribute("userInfo",userInfo);
%>
<a href="GetMapDemo.jsp">跳轉到GetMapDemo.jsp</a>
</body>
</html>
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>使用存儲器讀取map中的數據</title>
</head>
<body>
用戶名：${sessionScope.userInfo.username}<br />
密碼：${sessionScope.userInfo.password}<br />
</body>
</html>
使用存儲器讀取數組中的數據
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@page import="java.util.*,com.javaweb.ch08.*" %>
<!DOCTYPE html>
<html>
<head>
<title>設置Array頁面</title>
</head>
<body>
<%
String[] names = {"zhangda1","zhangda2","zhangda3"};
//將值存儲到session范圍中
session.setAttribute("names",names);
%>
<a href="GetMapDemo.jsp">跳轉到GetArrayDemo.jsp</a>
</body>
</html>
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>使用存儲器讀取map中的數據</title>
</head>
<body>
用戶名1：${sessionScope.names[0]}<br />
用戶名2：${sessionScope.names[1]}<br />
</body>
</html>
存儲器的復雜應用
<%@page language="java" contentType="text/html;charset=gb2312"%>
<%@page import="java.util.*,com.javaweb.ch08.*" %>
<!DOCTYPE html>
<html>
<head>
<title>設置Array頁面</title>
</head>
<body>
<%
ArrayList<Person> persons = new ArrayList<Person>();
Person person1 = new Person("wang wu",24,"男");
Person person2 = new Person("wang liu",24,"女");
persons.add(person1);
persons.add(person2);
session.setAttribute("persons",persons);
%>
<a href="GetMapDemo.jsp">跳轉到GetArrayDemo.jsp</a>
</body>
</html>
<%@page language="java" contentType="text/html;charset=gb2312"%>
<!DOCTYPE html>
<html>
<head>
<title>使用存儲器讀取map中的數據</title>
</head>
<body>
用戶名1：${sessionScope.persons[0].name},${sessionScope.persons[0].age},${sessionScope.persons[0].sex}<br />
用戶名2：${sessionScope.persons[1].name},${sessionScope.persons[1].age},${sessionScope.persons[1].sex}<br />
</body>
</html>
