java_jsp_exday05

练习列表

编号名称描述级别

1 el表达式**

2 JSTL核心标签** 注："*"理解级别"**"掌握级别"***"应用级别

目录

1. 练习1：el表达式**........................................................................................................ 错误！未定义书签。

2. 练习2：JSTL核心标签** (9)

练习1：el表达式**

第一种：访问bean的属性

1)User.java

package bean;

public class User {

private String name;

private int age;

private IdCard card;

private String[] interest;

public String[] getInterest() {

return interest;

}

public void setInterest(String[] interest) {

this.interest = interest;

}

public IdCard getCard() {

return card;

}

public void setCard(IdCard card) {

this.card = card;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

https://www.wendangku.net/doc/ed3976677.html, = name;

}

}

2)IdCard.java

package bean;

public class IdCard {

private String cardNo;

public String getCardNo() {

return cardNo;

}

public void setCardNo(String cardNo) {

this.cardNo = cardNo;

}

}

3)el01.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@page import="bean.*" %>

<%

User user = new User();

user.setName("abc");

user.setAge(22);

IdCard card = new IdCard();

card.setCardNo("100");

user.setCard(card);

user.setInterest(

new String[]{"fishing","sleep"});

request.setAttribute("user1",user);

%>

<%

//User user1 =

// (User)request.getAttribute("user1");

//out.println(user1.getName());

//out.println(user1.getAge());

%>

${https://www.wendangku.net/doc/ed3976677.html,}

${user1.age}

${user1.card.cardNo}

${user1["name"]}

<%

request.setAttribute("propname","name");

%>

${user1[propname]};

${user1.interest[1]}

user's name:${https://www.wendangku.net/doc/ed3976677.html,}

4)访问http://localhost:8080/web10_el/el01.jsp

第二种：获得请求参数值

5)el02.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

username:${https://www.wendangku.net/doc/ed3976677.html,ername}

interest:${paramValues.interest[1]}

interest:${paramValues.interest[0]}

6)访问

http://localhost:8080/web10_el/el02.jsp

?username=zz&&interest=fishing&interest=cooking

第三种：计算一个表达式，将结果作为标签的属性值或者直接输出

7)el03.jsp

<%@ page import="java.util.*"

contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

${1+2}

${"123" + "567" }

${"abc" == "abc"}

${"abc" eq "abc" }

<%

pageContext.setAttribute("str","abc");

%>

${"abc" eq str }

<%

request.setAttribute("str1","");

List list = new ArrayList();

request.setAttribute("list1",list);

request.setAttribute("obj1",null);

%>

空字符结果为true:

${empty str1}

找不到绑订名对应的对象，结果是true:

${empty obj}

集合内容为空，结果为true:

${empty list1}

null，结果为true:

${empty obj1}

8)访问http://localhost:8080/web10_el/el03.jsp

练习2：JSTL核心标签**

1)拷贝Jar包standard.jar、jstl.jar

C:\Program Files\MyEclipse

6.0\myeclipse\eclipse\plugins\com.genuitec.eclipse.j2eedt.core_6.0.1.zmyeclipse60120071

0\data\libraryset\JSTL1.1\lib

2)*.tld文件

*.tld文件是标签的描述文件。

3)新建https://www.wendangku.net/doc/ed3976677.html,er

package bean;

public class User {

private String name;

private String gendar;

public String getGendar() {

return gendar;

}

public void setGendar(String gendar) {

this.gendar = gendar;

}

public String getName() {

return name;

}

public void setName(String name) {

https://www.wendangku.net/doc/ed3976677.html, = name;

}

}

4)新建jstl01.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@page import="https://www.wendangku.net/doc/ed3976677.html,er" %>

<%@taglib prefix="c" uri="https://www.wendangku.net/doc/ed3976677.html,/jsp/jstl/core"%>

<%

User user = new User();

user.setName("zs");

user.setGendar("f");

request.setAttribute("user1",user);

%>

user's name:${https://www.wendangku.net/doc/ed3976677.html,}

user's gendar:

var="rs" scope="request">

男

女

5)访问http://localhost:8080/web10_jstl/jstl01.jsp

6)新建jstl02.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@page import="https://www.wendangku.net/doc/ed3976677.html,er" %>

<%@taglib prefix="c" uri="https://www.wendangku.net/doc/ed3976677.html,/jsp/jstl/core"%>

<%

User user = new User();

user.setName("zs");

user.setGendar("f");

request.setAttribute("user1",user);

%>

user's gendar:

男

女

7)访问http://localhost:8080/web10_jstl/jstl02.jsp

8)新建jstl03.jsp

9)访问http://localhost:8080/web10_jstl/jstl03.jsp

10)修改jstl03.jsp

修改显示样式

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@page import="https://www.wendangku.net/doc/ed3976677.html,er,java.util.*" %>

<%@taglib prefix="c" uri="https://www.wendangku.net/doc/ed3976677.html,/jsp/jstl/core"%>

<%

List users = new ArrayList();

User user1 = new User();

user1.setName("zs");

user1.setGendar("f");

User user2 = new User();

user2.setName("ww");

user2.setGendar("m");

users.add(user1);

users.add(user2);

request.setAttribute("users",users);

%>

cellpadding="0" cellspacing="0">

11)访问http://localhost:8080/web10_jstl/jstl03.jsp

12)修改jstl03.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@page import="https://www.wendangku.net/doc/ed3976677.html,er,java.util.*" %>

<%@taglib prefix="c" uri="https://www.wendangku.net/doc/ed3976677.html,/jsp/jstl/core"%>

cellspacing="0">

13)新建ActionServlet

package web;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;

import https://www.wendangku.net/doc/ed3976677.html,er;

public class ActionServlet extends HttpServlet {

public void service(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException { String uri = request.getRequestURI();

String path = uri.substring(https://www.wendangku.net/doc/ed3976677.html,stIndexOf("/"),

https://www.wendangku.net/doc/ed3976677.html,stIndexOf("."));

if(path.equals("/list")){

List users = new ArrayList();

User user = new User();

user.setName("zs");

user.setGendar("m");

users.add(user);

User user2 = new User();

user2.setName("ww");

user2.setGendar("m");

users.add(user2);

User user3 = new User();

user3.setName("sd");

user3.setGendar("f");

users.add(user3);

request.setAttribute("users",users);

request

.getRequestDispatcher("jstl03.jsp")

.forward(request, response);

}

}

}

14)web.xml

xmlns="https://www.wendangku.net/doc/ed3976677.html,/xml/ns/j2ee"

xmlns:xsi="https://www.wendangku.net/doc/ed3976677.html,/2001/XMLSchema-instance"

xsi:schemaLocation="https://www.wendangku.net/doc/ed3976677.html,/xml/ns/j2ee

https://www.wendangku.net/doc/ed3976677.html,/xml/ns/j2ee/web-app_2_4.xsd">

ActionServlet

web.ActionServlet

ActionServlet

*.do

index.jsp

15)访问http://localhost:8080/web10_jstl/list.do

同样显示结果

16)新建jstl04.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

<%@taglib prefix="c"

uri="https://www.wendangku.net/doc/ed3976677.html,/jsp/jstl/core"%>

<%

session.setAttribute("username","zs");

%>

访问jstl05

17)新建jstl05.jsp

<%@ page contentType="text/html; charset=utf-8"

pageEncoding="utf-8"%>

username:${https://www.wendangku.net/doc/ed3976677.html,ername}

18)当禁用Cookie时

19)访问http://localhost:8080/web10_jstl/jstl04.jsp

a.点击链接将访问jsp05.jsp