EL-获取域中存储的值-对象值、EL-获取域中存储的值-List集合&Map集合值

EL-获取域中存储的值-对象值

　　1. 对象：${域名称.键名.属性名}

　　　　本质上会去调用对象的getter方法

User类

package com.example.day_17_eljstl.domain;

import java.text.SimpleDateFormat;
import java.util.Date;

public class User {

    private String name;
    private int age;
    private Date birthday;


    public User(String name, int age, Date birthday) {
        this.name = name;
        this.age = age;
        this.birthday = birthday;
    }

    public User() {
    }

    /**
     * 逻辑视图
     * @return
     */
    public String getBirStr(){

        if(birthday != null){
            //1.格式化日期对象
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            //2.返回字符串即可
            return sdf.format(birthday);

        }else{
            return "";
        }
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

JSP

<%@ page import="cn.itcast.domain.User" %>
<%@ page import="java.util.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>el获取数据</title>
</head>
<body>

    <%
        User user = new User();
        user.setName("张三");
        user.setAge(23);
        user.setBirthday(new Date());


        request.setAttribute("u",user);


        List list = new ArrayList();
        list.add("aaa");
        list.add("bbb");
        list.add(user);

        request.setAttribute("list",list);


        Map map = new HashMap();
        map.put("sname","李四");
        map.put("gender","男");
        map.put("user",user);

        request.setAttribute("map",map);

    %>

<h3>el获取对象中的值</h3>
${requestScope.u}<br>

<%--
    * 通过的是对象的属性来获取
        * setter或getter方法，去掉set或get，在将剩余部分，首字母变为小写。
        * setName --> Name --> name
--%>

    ${requestScope.u.name}<br>
    ${u.age}<br>
    ${u.birthday}<br>
    ${u.birthday.month}<br>

    ${u.birStr}<br>

</body>
</html>

EL-获取域中存储的值-List集合&Map集合值

List集合、Map集合的值

　　 List集合：

　　　　${域名称.键名[索引]}

　　 Map集合：
　　　　${域名称.键名.key名称}
　　　　${域名称.键名["key名称"]}

<%@ page import="cn.itcast.domain.User" %>
<%@ page import="java.util.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>el获取数据</title>
</head>
<body>

    <%
        User user = new User();
        user.setName("张三");
        user.setAge(23);
        user.setBirthday(new Date());


        request.setAttribute("u",user);


        List list = new ArrayList();
        list.add("aaa");
        list.add("bbb");
        list.add(user);

        request.setAttribute("list",list);


        Map map = new HashMap();
        map.put("sname","李四");
        map.put("gender","男");
        map.put("user",user);

        request.setAttribute("map",map);

    %>

<h3>el获取对象中的值</h3>
${requestScope.u}<br>

<%--
    * 通过的是对象的属性来获取
        * setter或getter方法，去掉set或get，在将剩余部分，首字母变为小写。
        * setName --> Name --> name
--%>

    ${requestScope.u.name}<br>
    ${u.age}<br>
    ${u.birthday}<br>
    ${u.birthday.month}<br>

    ${u.birStr}<br>

    <h3>el获取List值</h3>
    ${list}<br>
    ${list[0]}<br>
    ${list[1]}<br>
    ${list[10]}<br>

    ${list[2].name}

    <h3>el获取Map值</h3>
    ${map.gender}<br>
    ${map["gender"]}<br>
    ${map.user.name}

</body>
</html>