EL表达式获取数据的方式

时间：2021-09-20 02:23:19
<%@page import="cn.jiemoxiaodi.domain.Person"%>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://"

            + request.getServerName() + ":" + request.getServerPort()

            + path + "/";

%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<base href="<%=basePath%>">

<title>My JSP 'demo1.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">

<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

<meta http-equiv="description" content="This is my page">

<!--

    <link rel="stylesheet" type="text/css" href="styles.css">

    -->

</head>

<body>

    <h3>传统方式获得的值</h3>

    <%

        pageContext.setAttribute("pageName", "pagVal");

        request.setAttribute("reqName", "reqVal");

        session.setAttribute("sessionName", "sessionVal");

        application.setAttribute("appName", "appVal");

    %>

    <%=pageContext.getAttribute("pageName")%>

    <%=request.getAttribute("reqName")%>

    <%=session.getAttribute("sessionName")%>

    <%=application.getAttribute("appName")%>

    <H3>使用EL表达式获得的值</H3>

    ${pageScope.pageName} ${requestScope.reqName}

    ${sessionScope.sessionName} ${applicationScope.appName} 简写 ${pageName}

    ${reqName}

    <h3>使用EL获得集合的值</h3>

    <%

        String[] str = new String[] { "张三", "lisi", "招六" };

        pageContext.setAttribute("str", str);

    %>

    ${str[0]} ${str[1]} ${str[2]}

    <h3>使用EL获得List集合的值</h3>

    <%

        List<String> tempList = new ArrayList<String>();

        tempList.add("张三");

        tempList.add("李四");

        tempList.add("王武");

        pageContext.setAttribute("ArrayLists", tempList);

    %>

    ${ArrayLists[0]} ${ArrayLists[1]} ${ArrayLists[2]}

    <h3>使用EL获得Map集合的值</h3>

    <%

        Map<String, String> tempMap = new HashMap<String, String>();

        tempMap.put("first", "zhangfirst");

        tempMap.put("second", "two");

        tempMap.put("third", "three");

        tempMap.put("four", "four");

        pageContext.setAttribute("Maps", tempMap);

    %>

    ${Maps.first} ${Maps.second} ${Maps.third} ${Maps.four}

    <h3>使用EL获得对象的值</h3>

    <%

        Person p = new Person();

        p.setName("小红");

        p.setAge(22);

        pageContext.setAttribute("p", p);

    %>

    ${p.name} ${p.age}

    <h3>使用EL获得集合中对象的数据</h3>

    <%

        List<Person> pList = new ArrayList<Person>();

        pList.add(new Person("张三", 22));

        pList.add(new Person("李四", 44));

        pageContext.setAttribute("pList", pList);

    %>

    ${pList[0].name} ${pList[0].age} ${pList[1].name} ${pList[1].age}

</body>

</html>

EL表达式获取数据的方式

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