Session详解，学习 Session对象一篇文章就够了 目录 1 Session概述 2 Session原理 3 Session使用 3.1 获取Session 3.2 Session保存数据 3.3 Session获取数据 3.4 Session移除数据 4 Session与Request应用区别 4.1 Session和request存储数据 4.2 获取session和request中的值 4.3 session和request区别效果 5 Session的声明周期 5.1 Session有效时间设置 5.2 session销毁 .6 浏览器禁用Cookie解决方案（了解） 6.1 浏览器禁用Cookie的后果 6.2 URL重写 6.3 实现URL重写 7 Session实战权限验证 7.1 创建管理员表manager并添加数据 7.2 创建Web项目 7.3 基础环境搭建 7.4 登录页面 7.5 LoginMgrController 7.6 ShowAllManagerController 7.7 ShowAllManagerJsp 8 Session实战保存验证码 8.1 创建验证码 8.2 登录页面 8.3 LoginMgrController 8.4 ShowAllManagerController 今天的分享就到此结束了 创作不易点赞评论互关三连 1 Session概述 （1）Session用于记录用户的状态。Session指的是一段时间内，单个客户端与Web服务器的一连串相关的交互过程。 （2）在一个Session中，客户可能会多次请求访问同一个资源，也有可能请求访问各种不同的服务器资源。 （3）Session是由服务器端创建的 2 Session原理 （1）Session会为每一次会话分配一个Session对象 （2）同一个浏览器发起的多次请求，同属于一次会话（Session） （3）首次使用到Session时，服务器会自动创建Session，并创建Cookie存储SessionId发送回客户端 3 Session使用 Session作用域：拥有存储数据的空间，作用范围是一次会话有效 一次会话是使用同一浏览器发送的多次请求。一旦浏览器关闭，则结束会话 可以将数据存入Session中，在一次会话的任意位置进行获取 可传递任何数据（基本数据类型、对象、集合、数组） 3.1 获取Session Session是服务器端自动创建的，通过request对象获取 package com.cxyzxc.www.servlet01; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; @WebServlet(name = "SessionServlet01", value = "/SessionServlet01") public class SessionServlet01 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象,首次使用到Session时，服务器会自动创建Session，并创建Cookie存储SessionId发送回客户端 HttpSession session = request.getSession(); System.out.println("ID:" + session.getId());//唯一标记 } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 3.2 Session保存数据 使用setArrtibute(属性名,Object)保存数据到session中 package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "SessionServlet02", value = "/SessionServlet02") public class SessionServlet02 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象,首次使用到Session时，服务器会自动创建Session，并创建Cookie存储SessionId发送回客户端 HttpSession session = request.getSession(); //将数据存储以键值对的形式到session对象中，可传递任何数据（基本数据类型、对象、集合、数组） session.setAttribute("username","张三"); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }   3.3 Session获取数据 （1）使用getAttribute("属性名");获取session中数据。 （2）先访问SessionServlet02将数据存储到session对象中，然后通过GetSessionValueServlet01请求获取session中的数据 package com.cxyzxc.www.servlet01; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet01", value = "/GetSessionValueServlet01") public class GetSessionValueServlet01 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //获取session对象中的值，获取的值是Object类型，转换为其对应的类型 String username = (String) session.getAttribute("username"); System.out.println("session对象中存储的username值：" + username); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 3.4 Session移除数据 （1）使用removeAttribute("属性名");从session中删除数据 （2）向请求SessionServlet02向session对象中存储数据，然后访问GetSessionValueServlet01可以获取session对象中的值，再访问SessionServlet03移除session对象中存储的数据，最后访问GetSessionValueServlet01获取session对象中的值为null package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "SessionServlet03", value = "/SessionServlet03") public class SessionServlet03 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象,首次使用到Session时，服务器会自动创建Session，并创建Cookie存储SessionId发送回客户端 HttpSession session = request.getSession(); //通过键移除session作用域中的值 session.removeAttribute("username"); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }   4 Session与Request应用区别 （1）request是一次请求有效，请求改变，则request改变 （2）session是一次会话有效，浏览器改变，则session改变 4.1 Session和request存储数据 package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "SessionServlet04", value = "/SessionServlet04") public class SessionServlet04 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //使用session存储数据 session.setAttribute("username","zhangsan"); //使用request存储数据 request.setAttribute("password","123456"); //重定向 response.sendRedirect("/webProject10_war_exploded/GetSessionValueServlet01"); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }   4.2 获取session和request中的值 package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet01", value = "/GetSessionValueServlet01") public class GetSessionAndRequestValueServlet01 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //获取session对象中的值，获取的值是Object类型，转换为其对应的类型 String username = (String) session.getAttribute("username"); //获取request对象中的值，获取的值是Object类型，转换为其对应的类型 String password = (String) request.getAttribute("password"); System.out.println("session对象中存储的username值：" + username); System.out.println("request对象中存储的password值：" + password); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 4.3 session和request区别效果 5 Session的声明周期 开始 第一次使用到Session的请求产生，则创建Session 结束 浏览器关闭，则失效 Session超时，则失效 session.setMaxInactiveInterval(seconds);//设置最大有效时间（单位：秒） 手工销毁，则失效 session.invalidate();//登录退出，销毁 5.1 Session有效时间设置 SessionServlet05类设置session有效期为20秒，先通过请求SessionServlet05类将session存储在，然后在20秒内第一次在GetSessionValueServlet02获取sessionID值，与SessionServlet05类中输出的id值一致，过20秒后在GetSessionValueServlet02类中输出的sessionID值不一致了   package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "SessionServlet05", value = "/SessionServlet05") public class SessionServlet05 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象,首次使用到Session时，服务器会自动创建Session，并创建Cookie存储SessionId发送回客户端 HttpSession session = request.getSession(); //设置session有效期,时间单位为秒 session.setMaxInactiveInterval(20); //输出sessionid值 System.out.println("SessionServlet05类中输出ID:"+session.getId()); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 5.2 session销毁 先使用GetSessionValueServlet03类获取session的id值，然后使用GetSessionValueServlet04类获取session的id值，两个类获取的id值一致，在GetSessionValueServlet04类中输出id值后销毁了session，然后再在GetSessionValueServlet03类中获取id值，就不一致了，就是服务器新建的session对象了 5.2.1 GetSessionValueServlet03类 package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet03", value = "/GetSessionValueServlet03") public class GetSessionValueServlet03 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //输出sessionid值 System.out.println("GetSessionValueServlet03类中输出ID:"+session.getId()); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }   5.2.2 GetSessionValueServlet04类 package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet04", value = "/GetSessionValueServlet04") public class GetSessionValueServlet04 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //输出sessionid值 System.out.println("GetSessionValueServlet04类中输出ID:"+session.getId()); //销毁session session.invalidate(); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } .6 浏览器禁用Cookie解决方案（了解） 6.1 浏览器禁用Cookie的后果 服务器在默认情况下，会使用Cookie的方式将sessionID发送给浏览器，如果用户禁止Cookie，则sessionID不会被浏览器保存，此时，服务器可以使用URL重写这样的方式来发送sessionID   多次请求GetSessionValueServlet05类输出的session的id值都不相同，并且在网站的Cookie对象中没有session的id值存在   6.2 URL重写 浏览器在访问服务器上的某个地址时，不再使用原来的那个地址，而是使用经过改写的地址（即在原来的地址后面加上了sessionID） 6.3 实现URL重写 response.encodeRedirectURL(String url)生成重写的URL 6.3.1 重写URL package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet06", value = "/GetSessionValueServlet06") public class GetSessionValueServlet06 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //输出sessionid值 System.out.println("GetSessionValueServlet06类中输出ID:"+session.getId()); //重写URL追加session值 String newURL = response.encodeURL("/webProject10_war_exploded/GetSessionValueServlet07"); System.out.println("重写后的URL："+newURL); //重定向 response.sendRedirect(newURL); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }   6.3.1 获取session package com.cxyzxc.www.servlet01; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "GetSessionValueServlet07", value = "/GetSessionValueServlet07") public class GetSessionValueServlet07 extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置请求参数的编码格式，这种方式对get请求方式无效 request.setCharacterEncoding("UTF-8"); //设置响应编码格式为UTF-8 response.setContentType("text/html;charset=UTF-8"); //获取Session对象 HttpSession session = request.getSession(); //输出sessionid值 System.out.println("GetSessionValueServlet07类中输出ID:"+session.getId()); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 7 Session实战权限验证   7.1 创建管理员表manager并添加数据   7.2 创建Web项目 创建Web项目，导入相关jar包 commons-dbutils-1.7.jar druid-1.1.5.jar mysql-connector-java-5.1.25-bin.jar servlet-api.jar 7.3 基础环境搭建 在项目下创建包目录结构如下 com.cxyzxc.www.controller包：调用业务逻辑Servlet com.cxyzxc.www.dao包：数据访问层接口 com.cxyzxc.www.dao.impl包：数据访问层接口实现类 com.cxyzxc.www.entity包：实体类 com.cxyzxc.www.jsp包：打印显示页面Servlet com.cxyzxc.www.service包：业务逻辑层接口 com.cxyzxc.www.service.impl包：业务逻辑层接口实现类 com.cxyzxc.www.utils包：工具类 database.properties:数据库连接及连接池配置文件 7.4 登录页面 7.4.1 login.html   7.4.2 login.css * { margin: 0; padding: 0; } div { width: 400px; background-color: #ccc; margin: 30px auto; padding-top: 30px; text-align: center; } p { margin-top: 10px; } input { outline: none; } 7.5 LoginMgrController package com.cxyzxc.www.controller; import com.cxyzxc.www.entity.Manager; import com.cxyzxc.www.service.ManagerService; import com.cxyzxc.www.service.impl.ManagerServiceImpl; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; @WebServlet(name = "LoginMgrController", value = "/LoginMgrController") public class LoginMgrController extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、处理乱码 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); //2、收参（获取客户端发送过来的请求数据） String username = request.getParameter("username"); String password = request.getParameter("password"); //3、调用业务方法 ManagerService managerService = new ManagerServiceImpl(); Manager manager = managerService.login(username, password); //4、处理结果，根据结果做不同的跳转 if (manager != null) {//manager不为null，说明账号和密码正确，登录成功 //将获取的账号和密码信息存储在session中 HttpSession session = request.getSession(); session.setAttribute("manager", manager); //跳转到显示所有管理员信息的Servlet response.sendRedirect("/managerProject01_war_exploded/ShowAllManagerController"); } else {//manager为null。说明账号或者密码错误，登录失败 response.sendRedirect("/managerProject01_war_exploded/login.html"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 7.6 ShowAllManagerController package com.cxyzxc.www.controller; import com.cxyzxc.www.entity.Manager; import com.cxyzxc.www.service.ManagerService; import com.cxyzxc.www.service.impl.ManagerServiceImpl; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; import java.util.List; @WebServlet(name = "ShowAllManagerController", value = "/ShowAllManagerController") public class ShowAllManagerController extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、处理乱码 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); //通过HttpSession完成权限控制 HttpSession session =request.getSession(); //获取session中存储的值 Manager manager = (Manager)session.getAttribute("manager"); //判断获取的值 if(manager!=null){ //调用业务,只做业务，业务与显示分离 ManagerService managerService = new ManagerServiceImpl(); List managers =managerService.showAllManager(); //将获取的数据存储在request作用域中 request.setAttribute("managers",managers); //转发，跳转到显示结果的Servlet request.getRequestDispatcher("/ShowAllManagerJsp").forward(request,response); }else{ //说明没有登录，要先去登录才能进行显示 response.sendRedirect("/managerProject01_war_exploded/login.html"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 7.7 ShowAllManagerJsp package com.cxyzxc.www.jsp; import com.cxyzxc.www.entity.Manager; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; import java.io.PrintWriter; import java.util.List; @WebServlet(name = "ShowAllManagerJsp", value = "/ShowAllManagerJsp") public class ShowAllManagerJsp extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、处理乱码 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); //2、获取数据 List managers = (List) request.getAttribute("managers"); //获取输出流 PrintWriter printWriter = response.getWriter(); if (managers.size() != 0) { printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(" "); printWriter.println(" "); printWriter.println(" "); printWriter.println(" "); printWriter.println(" "); for (int i = 0; i < managers.size(); i++) { printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); printWriter.println(""); } printWriter.println("

序号	账号	密码	操作
" + (i + 1) + "	" + managers.get(i).getUsername() + "	" + managers.get(i).getPassword() + "	修改 删除

"); printWriter.println(""); } else { printWriter.println("

数据库中没有数据查询

"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 8 Session实战保存验证码 生成验证码的方式有很多种，可以使用随机数的方式实现，也可以使用ValidateCode类来实现（需要导入ValidateCode.jar包）。在这里，我们学习使用ValidateCode类来生成验证码 8.1 创建验证码 package com.cxyzxc.www.controller; import cn.dsna.util.images.ValidateCode; import javax.servlet.*; import javax.servlet.http.*; import javax.servlet.annotation.*; import java.io.IOException; / * 此Servlet的作用是生成验证码并将生成的验证码存储到session中、发送到页面中显示 */ @WebServlet(name = "VerificationServlet", value = "/VerificationServlet") public class VerificationServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置验证码规格 ValidateCode validateCode = new ValidateCode(200, 20, 4, 10); //获取验证码 String code = validateCode.getCode(); //将验证码存储在session中 HttpSession session = request.getSession(); session.setAttribute("code",code); //将验证码输出到客户端 validateCode.write(response.getOutputStream()); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 8.2 登录页面

账号：

密码：

验证码：

8.3 LoginMgrController package com.cxyzxc.www.controller; import com.cxyzxc.www.entity.Manager; import com.cxyzxc.www.service.ManagerService; import com.cxyzxc.www.service.impl.ManagerServiceImpl; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "LoginMgrController", value = "/LoginMgrController") public class LoginMgrController extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、处理乱码 request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); //2、收参（获取客户端发送过来的请求数据） String username = request.getParameter("username"); String password = request.getParameter("password"); String inputCodde = request.getParameter("verification"); //获取session中的验证码 HttpSession session = request.getSession(); String codes = (String) session.getAttribute("code"); if (!inputCodde.isEmpty() && inputCodde.equalsIgnoreCase(codes)) { //3、调用业务方法 ManagerService managerService = new ManagerServiceImpl(); Manager manager = managerService.login(username, password); //4、处理结果，根据结果做不同的跳转 if (manager != null) {//manager不为null，说明账号和密码正确，登录成功 //将获取的账号和密码信息存储在session中 HttpSession session2 = request.getSession(); session2.setAttribute("manager", manager); //跳转到显示所有管理员信息的Servlet response.sendRedirect("/managerProject02_war_exploded/ShowAllManagerController"); } else {//manager为null。说明账号或者密码错误，登录失败 response.sendRedirect("/managerProject02_war_exploded/login.html"); } } else {//验证码不对，重新登录 response.sendRedirect("/managerProject02_war_exploded/login.html"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 8.4 ShowAllManagerController package com.cxyzxc.www.controller; import com.cxyzxc.www.entity.Manager; import com.cxyzxc.www.service.ManagerService; import com.cxyzxc.www.service.impl.ManagerServiceImpl; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; import java.util.List; @WebServlet(name = "ShowAllManagerController", value = "/ShowAllManagerController") public class ShowAllManagerController extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //通过HttpSession完成权限控制 HttpSession session =request.getSession(); //获取session中存储的值 Manager manager = (Manager)session.getAttribute("manager"); //判断获取的值 if(manager!=null){ //调用业务,只做业务，业务与显示分离 ManagerService managerService = new ManagerServiceImpl(); List managers =managerService.showAllManager(); //将获取的数据存储在request作用域中 request.setAttribute("managers",managers); //转发，跳转到显示结果的Servlet request.getRequestDispatcher("/ShowAllManagerJsp").forward(request,response); }else{ //说明没有登录，要先去登录才能进行显示 response.sendRedirect("/managerProject02_war_exploded/login.html"); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } 今天的分享就到此结束了 创作不易点赞评论互关三连