JSP页面使用EL表达式获取域对象中的值

冷不防 2022-12-27 07:44 215阅读 0赞

<%@ page import="cn.gpxxg.domain.User" %>
    <%@ page import="java.util.*" %>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>JSP页面使用EL表达式获取域对象中的值</title>
    </head>
    <body>
    
    <%--JSP中域对象有四个，范围从小到依次为pageContext->request->session->application--%>
    <%--在EL表达式中分别使用pageScope、requestScope、sessionScope、applicationScope获取值--%>
    
    <%
        // El获取普通的值
        pageContext.setAttribute("name", "张三");
    
        // El获取对象的值
        User user = new User();
        user.setUsername("李四");
        user.setAge(28);
        user.setBirthday(new Date());
        pageContext.setAttribute("user", user);
    
        // El获取List的值
        List list  = new ArrayList();
        list.add("王五");
        list.add("赵六");
        pageContext.setAttribute("list", list);
    
        // El获取Map的值
        Map map = new HashMap();
        map.put("name", "田七");
        map.put("gender", "女");
        pageContext.setAttribute("map", map);
    
        // 将map添加到list中，也可以获取
        list.add(map);
    %>
    
    <h1>El获取普通的值</h1>
    ${ name }<br>
    
    <h1>El获取对象的值</h1>
    ${ user.username }<br>
    ${ pageScope.user.birthday }<br>
    ${ pageScope.user.birStr }<br>
    
    <h1>El获取List的值</h1>
    ${ pageScope.list[1] }<br>
    ${ pageScope.list[2]}<br>
    ${ pageScope.list[2]['name']}<br>
    
    <h1>El获取Map的值</h1>
    ${ pageScope.map['gender'] }<br>
    ${ pageScope.map.name }<br>
    
    </body>
    </html>