JSP EL表达式使用

JSP EL表达式使用：

Servlet:

package com.stono.servlet;

import java.io.IOException;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.stono.servlet.bean.Dog;

import com.stono.servlet.bean.Person;

import com.stono.servlet.bean.Toy;

public class TestServlet6 extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        Person person = new Person();

        Dog dog = new Dog();

        Toy toy = new Toy();

        toy.setName("toyName");

        dog.setName("dogName");

        dog.setToy(toy);

        person.setDog(dog);

        person.setName("personName");

        req.setAttribute("person", person);

        String[] musics = new String[] { "m1", "m2", "m3" };

        req.setAttribute("musics", musics);

        Map<String, Object> map = new HashMap<String, Object>();

        map.put("a", "ma");

        map.put("b", "mb");

        map.put("c", "mc");

        req.setAttribute("map", map);

        Map<String, Object> map2 = new HashMap<String, Object>();

        map2.put("a", "m2a");

        req.setAttribute("map2", map2);

        req.setAttribute("aref", "a");

        RequestDispatcher dispatcher = req.getRequestDispatcher("index016.jsp");

        dispatcher.forward(req, resp);

    }

}

JSP:

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

<%

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

    pageContext.setAttribute("pca", "pageContextAttribute");

    //session.setAttribute("s", "session");

%>

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>016</title>

</head>

<body>

    <p>JSP生成的java文件中，EL表达式使用统一的方式进行数据读取；</p>

    <p>EL result is : ${pageScope.pca }</p>

    <p>person.name is : ${person.name }</p>

    <p>person.dog.name is : ${person.dog.name }</p>

    <p>musics[0] is : ${musics[0]}</p>

    <p>musics["1"] is : ${musics["1"]}</p>

    <p>musics["2"] is : ${musics[1+1]}</p>

    <p>map[a] is : ${map[a] }</p>

    <p>map["a"] is : ${map["a"] }</p>

    <p>map.a is : ${map.a }</p>

    <p>[]中没有引号，就会计算括号中的内容：</p>

    <p>map2[aref] is : ${map2[aref] }</p>

    <p>map2["aref"] is : ${map2["aref"] }</p>

    <p>person.dog.toy.name is : ${person.dog.toy.name}</p>

    <p>XXX is : ${XXX }</p>

    <p>

        ${pageScope }

        ${requestScope }

        ${sessionScope }

        ${applicationScope }

        ${param }

        ${paramValues }

        ${header }

        ${headerValues }

        ${cookie }

        ${initParam }

        ${pageContext }

    </p>

</body>

</html>

JSP转换生成的Java：

/*

 * Generated by the Jasper component of Apache Tomcat

 * Version: Apache Tomcat/7.0.35

 * Generated at: 2015-10-30 00:31:49 UTC

 * Note: The last modified time of this file was set to

 *       the last modified time of the source file after

 *       generation to assist with modification tracking.

 */

package org.apache.jsp;

import javax.servlet.*;

import javax.servlet.http.*;

import javax.servlet.jsp.*;

import java.util.*;

public final class index016_jsp extends org.apache.jasper.runtime.HttpJspBase

    implements org.apache.jasper.runtime.JspSourceDependent {

  private static final javax.servlet.jsp.JspFactory _jspxFactory =

          javax.servlet.jsp.JspFactory.getDefaultFactory();

  private static java.util.Map<java.lang.String,java.lang.Long> _jspx_dependants;

  private javax.el.ExpressionFactory _el_expressionfactory;

  private org.apache.tomcat.InstanceManager _jsp_instancemanager;

  public java.util.Map<java.lang.String,java.lang.Long> getDependants() {

    return _jspx_dependants;

  }

  public void _jspInit() {

    _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();

    _jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig());

  }

  public void _jspDestroy() {

  }

  public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response)

        throws java.io.IOException, javax.servlet.ServletException {

    final javax.servlet.jsp.PageContext pageContext;

    javax.servlet.http.HttpSession session = null;

    final javax.servlet.ServletContext application;

    final javax.servlet.ServletConfig config;

    javax.servlet.jsp.JspWriter out = null;

    final java.lang.Object page = this;

    javax.servlet.jsp.JspWriter _jspx_out = null;

    javax.servlet.jsp.PageContext _jspx_page_context = null;

    try {

      response.setContentType("text/html;charset=UTF-8");

      pageContext = _jspxFactory.getPageContext(this, request, response,

                  null, true, 8192, true);

      _jspx_page_context = pageContext;

      application = pageContext.getServletContext();

      config = pageContext.getServletConfig();

      session = pageContext.getSession();

      out = pageContext.getOut();

      _jspx_out = out;

      out.write('\r');

      out.write('\n');

    String path = request.getContextPath();

    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";

    pageContext.setAttribute("pca", "pageContextAttribute");

    //session.setAttribute("s", "session");

      out.write("\r\n");

      out.write("<!DOCTYPE html>\r\n");

      out.write("<html>\r\n");

      out.write("<head>\r\n");

      out.write("<meta charset=\"UTF-8\">\r\n");

      out.write("<title>016</title>\r\n");

      out.write("</head>\r\n");

      out.write("<body>\r\n");

      out.write("\t<p>EL result is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${pageScope.pca }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>person.name is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${person.name }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>person.dog.name is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${person.dog.name }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>musics[0] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${musics[0]}", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>musics[\"1\"] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${musics[\"1\"]}", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>musics[\"2\"] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${musics[1+1]}", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>map[a] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${map[a] }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>map[\"a\"] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${map[\"a\"] }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>map.a is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${map.a }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>[]中没有引号，就会计算括号中的内容：</p>\r\n");

      out.write("\t<p>map2[aref] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${map2[aref] }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>map2[\"aref\"] is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${map2[\"aref\"] }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>person.dog.toy.name is : ");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${person.dog.toy.name}", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("</p>\r\n");

      out.write("\t<p>\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${pageScope }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${requestScope }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${sessionScope }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${applicationScope }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${param }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${paramValues }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${header }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${headerValues }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${cookie }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${initParam }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t\t");

      out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate("${pageContext }", java.lang.String.class, (javax.servlet.jsp.PageContext)_jspx_page_context, null, false));

      out.write("\r\n");

      out.write("\t</p>\r\n");

      out.write("</body>\r\n");

      out.write("</html>\r\n");

    } catch (java.lang.Throwable t) {

      if (!(t instanceof javax.servlet.jsp.SkipPageException)){

        out = _jspx_out;

        if (out != null && out.getBufferSize() != 0)

          try { out.clearBuffer(); } catch (java.io.IOException e) {}

        if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);

        else throw new ServletException(t);

      }

    } finally {

      _jspxFactory.releasePageContext(_jspx_page_context);

    }

  }

}

JSP EL表达式使用的更多相关文章

Jsp,EL表达式的入门
Jsp,EL表达式的入门 *Servlet/JSP 是两种动态的WEB资源的两种技术使用Servlet生成HTML的页面是可以的 response.getWriter("<form ...
jsp EL表达式字符串的比较
jsp EL表达式字符串的比较跟JavaScript一样,直接使用两个等于号即可:== 代码如下: <c:if test="${highLight == 'visa'}" ...
JSP EL表达式获得 request的GET/POST方法
JSP EL表达式获得 request的GET/POST方法: 不在requestScopse中: <p>得到request的方法</p> <p>pageCont ...
JSP EL表达式 param、paramValues的使用
JSP EL表达式 param.paramValues的使用: <%@ page language="java" import="java.util.*" ...
JSP EL表达式忽略方法
JSP EL表达式忽略方法: web.xml中,和jsp中:jsp中的等级要高一些: web.xml: <?xml version="1.0" encoding=" ...
jsp EL表达式和JSTL标签if-else if-else用法
java web javaEE ,jsp EL表达式和JSTL标签if-else if-else四种用法一.条件运算符 ${user.gender==?'男':'女'} 二.if() <c:if ...
11 JSP/EL表达式/EL函数
JSP * 概述: JSP(Java Server Pages)与Java Servlet一样,是在服务器端执行的不同的是先由服务器编译部署成Servlet执行 * JSP的运行原 ...
JSP EL表达式（转）
一.EL简介 1.语法结构 ${expression}2.[]与.运算符 EL 提供.和[]两种运算符来存取数据. 当要存取的属性名称中包含一些特殊字符,如.或?等并非字母或数字 ...
JSP EL表达式
1 EL表达式简介 EL 全名为Expression Language.EL主要作用: 1.获取数据 EL表达式主要用于替换JSP页面中的脚本表达式,以从各种类型的web域中检索java对象.获取数 ...

随机推荐

ecos的mvcl
m 数据模型抽象层 v 视图 c 控制器 l 业务逻辑 mvc与mvcl区别 mvc中的m是mvcl中m+l
PAT (Advanced Level) 1029. Median (25)
scanf读入居然会超时...用了一下输入挂才AC... #include<cstdio> #include<cstring> #include<cmath> #i ...
JavaScript（三）---- 控制流程语句
常用的控制流程语句有判断语句.分支语句.循环语句.基本用法都和java中的一致,switch有几点特殊. 1.判断语句格式: if(判断条件){ 符合条件执行的代 ...
PHP学习笔记--1，不总结，不掌握，不明白！
不总结,不掌握,不明白! 前言: 学php一开始就是语法,变量,数组,函数,OOP(面向对象[封装,继承,多态,抽象]) 这些都是最基础的东西,但你还要懂一些在实际开发中要用的东西,比如基本的HTML ...
css一行内容过多显示省略号
四个缺一不可. 效果如下图
css中元素水平垂直居中4种方法介绍
table-cell轻松设置文本图片水平垂直居中让一个元素垂直居中的思路:把这个元素的容器设置为table-cell,也就是具有表格单元格的特性,再使用vertical-align(这个属性对blo ...
UWSGITOP-----监控uwsgi 性能
启动 uwsgi -x etc/bfdds_cookiemapping_conf.xml --stats /tmp/stats.socket 查看 uwsgitop /tmp/stats.socket ...
Quick Cocos2dx controller的初步实现
很久没有记笔记了,今天记一下,最近都在瞎忙活,都不知道自己干了些啥. 我的Controller是在官方的mvc sample的里面的PlayerDualController上更改的,所以很多地方还没来 ...
unity3d 之本地推送
1. 本地推送主要包括在android和ios上,下面所有的代码都是本人写的,经过测试是没有问题的,已经运用到项目中了.首先是接口INotification: using System; public ...
sed与正则用法收集
1.将文本每行最后七个字符换成!号 sed -n 's#.\{7\}$#!#p' ooo 在文本的每一行前添加#符号 sed 's/^.\?/#&/' passwd & 替代 ...

JSP EL表达式使用

JSP EL表达式使用的更多相关文章

随机推荐

热门专题