jsp页面jstl和el表达式

朱雀 2024-02-19 22:08 15阅读 0赞

注：因长期写后端代码导致前端代码基本快忘光了。再次总结一番，以备以后用

总结：

## 1：jsp中参数和属性： ##

### a) 参数parameter:来源有三： ###

i:web.xml或注解中设置的

ii：表单提交及url中设置的

iii: 超链接中获取的

### b):属性：四种范围，可选任何类型。属性除了javabean中都需要自己手动设置。 ###

i:page,request,session,Application

## 2：el的用法： ##

a):简单类型：范围.属性

b)类实例：范围。属性名.字段名

c):数组：$\{list\[0\].name\}

## 3:jstl：<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %> ##

在jstl中输出要用 <c:out value="el表达式"></c:out>

<%@ page import="com.xm.workflow.entity.TestUser" %>
    <%@ page import="net.sf.json.JSONArray" %>
    <%@ page import="java.util.*" %>
    <%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
    <%--
      Created by IntelliJ IDEA.
      User: 86156
      Date: 2019/8/15
      Time: 17:14
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%
        String data = " [{\n" +
                "                \"id\": 839707,\n" +
                "                \"oldFileName\": \"体育-跑酷.png\",\n" +
                "                \"newFileName\": \"eca3b34c-8415-4915-ab9c-68749af6c3ad\",\n" +
                "                \"fileSize\": 1285,\n" +
                "                \"fileType\": \".png\",\n" +
                "                \"createTime\": \"2019-08-12 17:20:43.0\",\n" +
                "                \"swfNum\": 0,\n" +
                "                \"contractId\": 6653,\n" +
                "                \"createUser\": \"lixin5\",\n" +
                "                \"updateUser\": \"lixin5\",\n" +
                "                \"updateTime\": \"2019-08-12 17:20:43.0\",\n" +
                "                \"status\": 0,\n" +
                "                \"fileUrl\": \"http://api.miren.test.mi.com/ua/contractAttach?id\\u003d839707\\u0026newFileName\\u003deca3b34c-8415-4915-ab9c-68749af6c3ad\"\n" +
                "            }]";
        JSONArray jsonArray = JSONArray.fromObject(data);
        request.setAttribute("jsonArray", jsonArray);
    
        int[] ages = {1, 2, 3, 4, 5}; // 普通数组，JSTL直接使用JSP赋值表达式来取
        List<String> names = new LinkedList<String>(); // List
    
        names.add("Biao");
    
        names.add("彪");
    
        names.add("雷");
    
        request.setAttribute("names", names); // 添加到request
        Map<String, String> map = new HashMap<String, String>(); // Map
    
        map.put("1", "黄彪");
    
        map.put("2", "丫头");
    
        map.put("3", "哥哥");
    
        map.put("4", "笨蛋");
    
        List<TestUser> users = new ArrayList<TestUser>(); // JavaBean的List
    
        users.add(new TestUser("黄彪", "xxxxxx"));
    
        users.add(new TestUser("昊天", "xxxxxx"));
    
        users.add(new TestUser("姐姐", "yyyyyy"));
    
        users.add(new TestUser("丫头", "zzzzzz"));
    
        session.setAttribute("users", users); // 添加到session
    %>
    <html>
    <head>
        <title>Title</title>
    </head>
    <body>
    <table border="1">
        
        <tr>
            <th>aaa</th>
            <c:forEach items="<%=ages%>" var="age">
                <th><c:out value="${age}"></c:out></th>
            </c:forEach>
        </tr>
    
        
        <tr>
            <c:forEach items="${names}" var="name">
                <th><c:out value="${name}"></c:out></th>
            </c:forEach>
        </tr>
        
        <tr>
            <c:forEach items="<%=names%>" var="name">
                <th><c:out value="${name}"></c:out></th>
            </c:forEach>
        </tr>
    </table>
    
    
    <table border="1">
    
        <tr>
    
            <th>Key</th>
    
            <th>Value</th>
    
        </tr>
    
        <c:forEach var="entry" items="<%= map %>">
    
            <tr>
    
                <td><c:out value="${entry.key}"/></td>
    
                <td><c:out value="${entry.value}"/></td>
    
            </tr>
    
        </c:forEach>
    
    </table>
    
    <table border="1">
        <tr>
            <th>username</th>
            <th>bz</th>
        </tr>
        <c:forEach items="${users}" var="user">
            <tr>
                <th><c:out value="${user.name}"></c:out></th>
                <th><c:out value="${user.bz}"></c:out></th>
            </tr>
        </c:forEach>
    
    </table>
    
    <table border="1">
        <c:forEach items="${jsonArray}" var="entrty">
            <tr>
                <th><c:out value="${entrty.id}"></c:out></th>
            </tr>
            <tr>
                <th><c:out value="${entrty.oldFileName}"></c:out></th>
            </tr>
            <tr>
                <th><c:out value="${entrty.newFileName}"></c:out></th>
            </tr>
            <tr>
                <th><h1>http://jtest.mioffice.cn:8080/mibpm/client/contract/downloadAttachFile?id=+<c:out
                        value="${entrty.id}"></c:out>&uid=<c:out value="${entrty.newFileName}"></c:out></h1></th>
            </tr>
            <tr>
                <th><a target="_blank" href="http://jtest.mioffice.cn:8080/mibpm/client/contract/downloadAttachFile?id=<c:out value="${entrty.id}"></c:out>&uid=+<c:out value="${entrty.newFileName}"></c:out>">点击链接</a>
                </th>
    
            </tr>
        </c:forEach>
    </table>
    
    </body>
    </html>