JavaWeb16.4【Cookie&Session：JSP入门】
index.jsp
1 <%-- 2 Created by IntelliJ IDEA. 3 User: yubaby 4 Date: 2021/7/2 5 Time: 14:35 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>$Title$</title> 12 </head> 13 <body> 14 15 <% 16 System.out.println("hello jsp, i'm back"); //输出到IDEA控制台 17 %> 18 <h1>hi,jsp</h1> <%--输出到浏览器页面--%> 19 20 21 <% response.getWriter().write("response....."); %> 22 23 <% //在Servlet的service方法中 24 System.out.println("hello jsp, i'm back"); 25 int i = 5; 26 27 String contextPath = request.getContextPath(); //request、response、out为内置对象，不用声明，可以直接用，因为servlet类中定义了 28 out.print(contextPath); // /day16 29 %> 30 <%! //在Servlet类的成员位置 31 int i = 3; 32 %> 33 <%= //输出到页面上 34 i //5，因为就近原则，service方法中定义的局部变量i的作用域较小 35 %> 36 <%= "hello" %> 37 38 <% response.getWriter().write("response*****"); %> 39 </body> 40 </html>
index_jsp.java
1 /* 2 * Generated by the Jasper component of Apache Tomcat 3 * Version: Apache Tomcat/8.5.31 4 * Generated at: 2021-07-02 12:33:12 UTC 5 * Note: The last modified time of this file was set to 6 * the last modified time of the source file after 7 * generation to assist with modification tracking. 8 */ 9 package org.apache.jsp; 10 11 import javax.servlet.*; 12 import javax.servlet.http.*; 13 import javax.servlet.jsp.*; 14 15 public final class index_jsp extends org.apache.jasper.runtime.HttpJspBase 16 implements org.apache.jasper.runtime.JspSourceDependent, 17 org.apache.jasper.runtime.JspSourceImports { 18 19 //在Servlet类的成员位置 20 int i = 3; 21 22 private static final javax.servlet.jsp.JspFactory _jspxFactory = 23 javax.servlet.jsp.JspFactory.getDefaultFactory(); 24 25 private static java.util.Map<java.lang.String,java.lang.Long> _jspx_dependants; 26 27 private static final java.util.Set<java.lang.String> _jspx_imports_packages; 28 29 private static final java.util.Set<java.lang.String> _jspx_imports_classes; 30 31 static { 32 _jspx_imports_packages = new java.util.HashSet<>(); 33 _jspx_imports_packages.add("javax.servlet"); 34 _jspx_imports_packages.add("javax.servlet.http"); 35 _jspx_imports_packages.add("javax.servlet.jsp"); 36 _jspx_imports_classes = null; 37 } 38 39 private volatile javax.el.ExpressionFactory _el_expressionfactory; 40 private volatile org.apache.tomcat.InstanceManager _jsp_instancemanager; 41 42 public java.util.Map<java.lang.String,java.lang.Long> getDependants() { 43 return _jspx_dependants; 44 } 45 46 public java.util.Set<java.lang.String> getPackageImports() { 47 return _jspx_imports_packages; 48 } 49 50 public java.util.Set<java.lang.String> getClassImports() { 51 return _jspx_imports_classes; 52 } 53 54 public javax.el.ExpressionFactory _jsp_getExpressionFactory() { 55 if (_el_expressionfactory == null) { 56 synchronized (this) { 57 if (_el_expressionfactory == null) { 58 _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory(); 59 } 60 } 61 } 62 return _el_expressionfactory; 63 } 64 65 public org.apache.tomcat.InstanceManager _jsp_getInstanceManager() { 66 if (_jsp_instancemanager == null) { 67 synchronized (this) { 68 if (_jsp_instancemanager == null) { 69 _jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig()); 70 } 71 } 72 } 73 return _jsp_instancemanager; 74 } 75 76 public void _jspInit() { 77 } 78 79 public void _jspDestroy() { 80 } 81 82 public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response) 83 throws java.io.IOException, javax.servlet.ServletException { 84 85 final java.lang.String _jspx_method = request.getMethod(); 86 if (!"GET".equals(_jspx_method) && !"POST".equals(_jspx_method) && !"HEAD".equals(_jspx_method) && !javax.servlet.DispatcherType.ERROR.equals(request.getDispatcherType())) { 87 response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, "JSPs only permit GET POST or HEAD"); 88 return; 89 } 90 91 final javax.servlet.jsp.PageContext pageContext; 92 javax.servlet.http.HttpSession session = null; 93 final javax.servlet.ServletContext application; 94 final javax.servlet.ServletConfig config; 95 javax.servlet.jsp.JspWriter out = null; 96 final java.lang.Object page = this; 97 javax.servlet.jsp.JspWriter _jspx_out = null; 98 javax.servlet.jsp.PageContext _jspx_page_context = null; 99 100 101 try { 102 response.setContentType("text/html;charset=UTF-8"); 103 pageContext = _jspxFactory.getPageContext(this, request, response, 104 null, true, 8192, true); 105 _jspx_page_context = pageContext; 106 application = pageContext.getServletContext(); 107 config = pageContext.getServletConfig(); 108 session = pageContext.getSession(); 109 out = pageContext.getOut(); 110 _jspx_out = out; 111 112 out.write("\n"); 113 out.write("\n"); 114 out.write("<html>\n"); 115 out.write(" <head>\n"); 116 out.write(" <title>$Title$</title>\n"); 117 out.write(" </head>\n"); 118 out.write(" <body>\n"); 119 out.write("\n"); 120 out.write(" "); 121 122 System.out.println("hello jsp, i'm back"); //输出到IDEA控制台 123 124 out.write("\n"); 125 out.write(" <h1>hi,jsp</h1> "); 126 out.write("\n"); 127 out.write("\n"); 128 out.write("\n"); 129 out.write(" "); 130 response.getWriter().write("response....."); 131 out.write("\n"); 132 out.write("\n"); 133 out.write(" "); 134 //在Servlet的service方法中 135 System.out.println("hello jsp, i'm back"); 136 int i = 5; 137 138 String contextPath = request.getContextPath(); //request、response、out为内置对象，不用声明，可以直接用，因为servlet类中定义了 139 out.print(contextPath); // /day16 140 141 out.write("\n"); 142 out.write(" "); 143 out.write("\n"); 144 out.write(" "); 145 out.print( //输出到页面上 146 i //5，因为就近原则，service方法中定义的局部变量i的作用域较小 147 ); 148 out.write("\n"); 149 out.write(" "); 150 out.print( "hello" ); 151 out.write("\n"); 152 out.write("\n"); 153 out.write(" "); 154 response.getWriter().write("response*****"); 155 out.write("\n"); 156 out.write(" </body>\n"); 157 out.write("</html>\n"); 158 } catch (java.lang.Throwable t) { 159 if (!(t instanceof javax.servlet.jsp.SkipPageException)){ 160 out = _jspx_out; 161 if (out != null && out.getBufferSize() != 0) 162 try { 163 if (response.isCommitted()) { 164 out.flush(); 165 } else { 166 out.clearBuffer(); 167 } 168 } catch (java.io.IOException e) {} 169 if (_jspx_page_context != null) _jspx_page_context.handlePageException(t); 170 else throw new ServletException(t); 171 } 172 } finally { 173 _jspxFactory.releasePageContext(_jspx_page_context); 174 } 175 } 176 }
apache-tomcat-8.5.31-src tomcat部分源码
HttpJspBase.java
1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.jasper.runtime; 19 20 import java.io.IOException; 21 22 import javax.servlet.ServletConfig; 23 import javax.servlet.ServletException; 24 import javax.servlet.http.HttpServlet; 25 import javax.servlet.http.HttpServletRequest; 26 import javax.servlet.http.HttpServletResponse; 27 import javax.servlet.jsp.HttpJspPage; 28 29 import org.apache.jasper.compiler.Localizer; 30 31 /** 32 * This is the super class of all JSP-generated servlets. 33 * 34 * @author Anil K. Vijendran 35 */ 36 public abstract class HttpJspBase extends HttpServlet implements HttpJspPage { 37 38 private static final long serialVersionUID = 1L; 39 40 protected HttpJspBase() { 41 } 42 43 @Override 44 public final void init(ServletConfig config) 45 throws ServletException 46 { 47 super.init(config); 48 jspInit(); 49 _jspInit(); 50 } 51 52 @Override 53 public String getServletInfo() { 54 return Localizer.getMessage("jsp.engine.info"); 55 } 56 57 @Override 58 public final void destroy() { 59 jspDestroy(); 60 _jspDestroy(); 61 } 62 63 /** 64 * Entry point into service. 65 */ 66 @Override 67 public final void service(HttpServletRequest request, HttpServletResponse response) 68 throws ServletException, IOException 69 { 70 _jspService(request, response); 71 } 72 73 @Override 74 public void jspInit() { 75 } 76 77 public void _jspInit() { 78 } 79 80 @Override 81 public void jspDestroy() { 82 } 83 84 protected void _jspDestroy() { 85 } 86 87 @Override 88 public abstract void _jspService(HttpServletRequest request, 89 HttpServletResponse response) 90 throws ServletException, IOException; 91 }
1 <%@ page import="java.net.URLDecoder" %> 2 <%@ page import="java.util.Date" %> 3 <%@ page import="java.text.SimpleDateFormat" %> 4 <%@ page import="java.net.URLEncoder" %><%-- 5 Created by IntelliJ IDEA. 6 User: yubaby 7 Date: 2021/7/2 8 Time: 20:49 9 To change this template use File | Settings | File Templates. 10 --%> 11 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 12 <html> 13 <head> 14 <title>Title</title> 15 </head> 16 <body> 17 18 <% 19 //设置响应的消息体的数据格式以及编码，防止中文乱码 20 // response.setContentType("text/html;charset=utf-8"); 21 22 //1 获取所有cookie 23 Cookie[] cookies = request.getCookies(); 24 boolean flag = false; //false表示没有名为lastTime的cookie 25 26 //2 遍历cookie数组 27 if (cookies!=null && cookies.length>0){ 28 for (Cookie cookie : cookies) { 29 //3 获取cookie的名称 30 String name = cookie.getName(); 31 //4 判断cookie名称是否为"lastTime" 32 if ("lastTime".equals(name)){ 33 //有该cookie，说明不是第一次访问 34 flag = true; 35 36 //(1) 响应数据 37 String value = cookie.getValue(); 38 //----------------------------------------- 39 //URL解码 40 System.out.println("解码前：" + value); 41 value = URLDecoder.decode(value, "utf-8"); 42 System.out.println("解码后：" + value); 43 //----------------------------------------- 44 // response.getWriter().write("<h1>欢迎回来，您上次访问时间为:" + value + "</h1>"); 45 // out.write("<h1>欢迎回来，您上次访问时间为:" + value + "</h1>"); //采用out输出不会影响页面布局 46 %> <%--jsp代码可以截断--%> 47 48 <h1>欢迎回来，您上次访问时间为:<%=value%></h1> 49 50 <% 51 //(2) 写回Cookie 52 Date date = new Date(); 53 SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss"); 54 String str_date = sdf.format(date); 55 //----------------------------------------- 56 //URL编码（在tomcat8之后，cookie支持中文数据，但如空格等特殊字符还是不支持） 57 System.out.println("编码前：" + str_date); 58 str_date = URLEncoder.encode(str_date, "utf-8"); 59 System.out.println("编码后：" + str_date); 60 //----------------------------------------- 61 cookie.setValue(str_date); 62 cookie.setMaxAge(60 * 60 * 24 * 30); //设置缓存一个月 63 response.addCookie(cookie); 64 65 break; 66 } 67 } 68 } 69 70 if (cookies==null || cookies.length==0 || flag==false){ 71 //无该cookie，说明是第一次访问 72 flag = true; 73 74 //(1) 响应数据 75 // response.getWriter().write("<h1>您好，欢迎您首次访问</h1>"); 76 // out.write("<h1>您好，欢迎您首次访问</h1>"); 77 %> 78 79 <h1>您好，欢迎您首次访问</h1> 80 81 <% 82 //(2) 写回Cookie 83 Date date = new Date(); 84 SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss"); 85 String str_date = sdf.format(date); 86 //----------------------------------------- 87 //URL编码 88 System.out.println("编码前：" + str_date); 89 str_date = URLEncoder.encode(str_date, "utf-8"); 90 System.out.println("编码后：" + str_date); 91 //----------------------------------------- 92 Cookie c = new Cookie("lastTime", str_date); 93 c.setMaxAge(60 * 60 * 24 * 30); //设置缓存一个月 94 response.addCookie(c); 95 } 96 %> 97 98 </body> 99 </html>
