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el表达式

时间:2021-06-02 17:00:39      阅读:0      评论:0      收藏:0      [点我收藏+]

标签:str   esc   port   object   get   ons   content   objects   页面   

<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.List" %><%--
  User: 丁帅帅
  Date: 21/05/30
  Time: 10:00
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
         ${3>4}
         \${3>4}
<hr>

        <h3>算术运算符</h3>
        ${3+4}<br>
        ${3/4}<br>
        ${1 div 4}<br>
        ${3 % 4}<br>
        ${3 mod 4}<br>


        <h3>比较运算符</h3>
        ${3 == 4}<br>

        <h3>逻辑运算符</h3>
        ${3 > 4  && 3 < 4}<br>
        ${3 > 4  and 3 < 4}<br>


        <h4>empty运算符</h4>
<%
    String str="";
    request.setAttribute("str",str);

    List<Object> objects = new ArrayList<>();
    request.setAttribute("list",objects);
%>
${empty str}
<br>
${not empty list}
</body>
</html>

  

<%--
  User: 丁帅帅
  Date: 21/05/30
  Time: 10:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>el获取域中的数据</title>
</head>
<body>
   <%
       request.setAttribute("name","李四");
       session.setAttribute("age",23);
   %>
<h3>el获取值</h3>
${requestScope.name}
<br>
${sessionScope.age}
<br>
${name}
</body>
</html>

  

package com.ding.domain;

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

/**
 * @Description TODO
 * @Author 丁帅帅
 * @Date 21/05/30 10:28
 * @Version 1.0
 */
public class User {
      private String name;
      private int age;
      private Date birthday;

    public User() {
    }

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

    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;
    }

    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
            return sdf.format(birthday);
        }
        return "";
    }
}




<%@ page import="com.ding.domain.User" %>
<%@ page import="java.util.*" %><%--
  User: 丁帅帅
  Date: 21/05/30
  Time: 10:39
  To change this template use File | Settings | File Templates.
--%>
<%@ 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);
%>
<%--
    * 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
--%>
<h3>el获取对象中的值</h3>
${requestScope.u}<br>
${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>

  

<%--
  User: 丁帅帅
  Date: 21/05/30
  Time: 11:13
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>el隐式对象</title>
</head>
<body>
${pageContext.request}<br>
<h4>在jsp页面动态获取虚拟目录</h4>
${pageContext.request.contextPath}<br>
</body>
</html>

  

el表达式

标签:str   esc   port   object   get   ons   content   objects   页面   

原文地址:https://www.cnblogs.com/dss-99/p/14827534.html

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