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Session详解，学习 Session对象一篇文章就够了_session撖寡情

作者：菜鸟追梦旅行 | 2024-02-27 02:35:05

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session撖寡情

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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.*;
  4. import javax.servlet.http.*;
  5. import javax.servlet.annotation.*;
  6. import java.io.IOException;
  7.  
  8. @WebServlet(name = "SessionServlet01", value = "/SessionServlet01")
  9. public class SessionServlet01 extends HttpServlet {
  10.     @Override
  11.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  12.         //设置请求参数的编码格式，这种方式对get请求方式无效
  13.         request.setCharacterEncoding("UTF-8");
  14.         //设置响应编码格式为UTF-8
  15.         response.setContentType("text/html;charset=UTF-8");
  16.  
  17.         //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
  18.         HttpSession session = request.getSession();
  19.         System.out.println("ID:" + session.getId());//唯一标记
  20.  
  21.     }
  22.  
  23.     @Override
  24.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  25.         doGet(request, response);
  26.     }
  27. }

3.2 Session保存数据

使用setArrtibute(属性名,Object)保存数据到session中

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "SessionServlet02", value = "/SessionServlet02")
  12. public class SessionServlet02 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //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
  21.         HttpSession session = request.getSession();
  22.  
  23.         //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）
  24.         session.setAttribute("username","张三");
  25.  
  26.     }
  27.  
  28.     @Override
  29.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  30.         doGet(request, response);
  31.     }
  32. }

 

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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.*;
  4. import javax.servlet.http.*;
  5. import javax.servlet.annotation.*;
  6. import java.io.IOException;
  7.  
  8. @WebServlet(name = "GetSessionValueServlet01", value = "/GetSessionValueServlet01")
  9. public class GetSessionValueServlet01 extends HttpServlet {
  10.     @Override
  11.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  12.         //设置请求参数的编码格式，这种方式对get请求方式无效
  13.         request.setCharacterEncoding("UTF-8");
  14.         //设置响应编码格式为UTF-8
  15.         response.setContentType("text/html;charset=UTF-8");
  16.  
  17.         //获取Session对象
  18.         HttpSession session = request.getSession();
  19.         //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
  20.         String username = (String) session.getAttribute("username");
  21.         System.out.println("session对象中存储的username值：" + username);
  22.     }
  23.  
  24.     @Override
  25.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  26.         doGet(request, response);
  27.     }
  28. }

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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "SessionServlet03", value = "/SessionServlet03")
  12. public class SessionServlet03 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //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
  21.         HttpSession session = request.getSession();
  22.  
  23.         //通过键移除session作用域中的值
  24.         session.removeAttribute("username");
  25.  
  26.     }
  27.  
  28.     @Override
  29.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  30.         doGet(request, response);
  31.     }
  32. }

 

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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "SessionServlet04", value = "/SessionServlet04")
  12. public class SessionServlet04 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.  
  23.         //使用session存储数据
  24.         session.setAttribute("username","zhangsan");
  25.         //使用request存储数据
  26.         request.setAttribute("password","123456");
  27.  
  28.         //重定向
  29.         response.sendRedirect("/webProject10_war_exploded/GetSessionValueServlet01");
  30.  
  31.     }
  32.  
  33.     @Override
  34.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  35.         doGet(request, response);
  36.     }
  37. }

 

4.2 获取session和request中的值

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "GetSessionValueServlet01", value = "/GetSessionValueServlet01")
  12. public class GetSessionAndRequestValueServlet01 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.         //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
  23.         String username = (String) session.getAttribute("username");
  24.         //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
  25.         String password = (String) request.getAttribute("password");
  26.  
  27.         System.out.println("session对象中存储的username值：" + username);
  28.         System.out.println("request对象中存储的password值：" + password);
  29.     }
  30.  
  31.     @Override
  32.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  33.         doGet(request, response);
  34.     }
  35. }

4.3 session和request区别效果

5 Session的声明周期

  1. 开始

    第一次使用到Session的请求产生，则创建Session

  2. 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

 

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "SessionServlet05", value = "/SessionServlet05")
  12. public class SessionServlet05 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //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
  21.         HttpSession session = request.getSession();
  22.  
  23.         //设置session有效期,时间单位为秒
  24.         session.setMaxInactiveInterval(20);
  25.  
  26.         //输出sessionid值
  27.         System.out.println("SessionServlet05类中输出ID:"+session.getId());
  28.  
  29.     }
  30.  
  31.     @Override
  32.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  33.         doGet(request, response);
  34.     }
  35. }

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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "GetSessionValueServlet03", value = "/GetSessionValueServlet03")
  12. public class GetSessionValueServlet03 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.  
  23.         //输出sessionid值
  24.         System.out.println("GetSessionValueServlet03类中输出ID:"+session.getId());
  25.  
  26.     }
  27.  
  28.     @Override
  29.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  30.         doGet(request, response);
  31.     }
  32. }

 

5.2.2 GetSessionValueServlet04类

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "GetSessionValueServlet04", value = "/GetSessionValueServlet04")
  12. public class GetSessionValueServlet04 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.  
  23.         //输出sessionid值
  24.         System.out.println("GetSessionValueServlet04类中输出ID:"+session.getId());
  25.  
  26.         //销毁session
  27.         session.invalidate();
  28.  
  29.     }
  30.  
  31.     @Override
  32.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  33.         doGet(request, response);
  34.     }
  35. }

.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

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "GetSessionValueServlet06", value = "/GetSessionValueServlet06")
  12. public class GetSessionValueServlet06 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.  
  23.         //输出sessionid值
  24.         System.out.println("GetSessionValueServlet06类中输出ID:"+session.getId());
  25.  
  26.         //重写URL追加session值
  27.         String newURL = response.encodeURL("/webProject10_war_exploded/GetSessionValueServlet07");
  28.         System.out.println("重写后的URL："+newURL);
  29.         //重定向
  30.         response.sendRedirect(newURL);
  31.  
  32.     }
  33.  
  34.     @Override
  35.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  36.         doGet(request, response);
  37.     }
  38. }

 

6.3.1 获取session

  1. package com.cxyzxc.www.servlet01;
  2.  
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import javax.servlet.http.HttpSession;
  9. import java.io.IOException;
  10.  
  11. @WebServlet(name = "GetSessionValueServlet07", value = "/GetSessionValueServlet07")
  12. public class GetSessionValueServlet07 extends HttpServlet {
  13.     @Override
  14.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  15.         //设置请求参数的编码格式，这种方式对get请求方式无效
  16.         request.setCharacterEncoding("UTF-8");
  17.         //设置响应编码格式为UTF-8
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //获取Session对象
  21.         HttpSession session = request.getSession();
  22.  
  23.         //输出sessionid值
  24.         System.out.println("GetSessionValueServlet07类中输出ID:"+session.getId());
  25.  
  26.  
  27.     }
  28.  
  29.     @Override
  30.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  31.         doGet(request, response);
  32.     }
  33. }

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

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

  1. <!DOCTYPE html>
  2. <html lang="en">
  3.     <head>
  4.         <meta charset="UTF-8">
  5.         <title>管理员登录页面</title>
  6.         <link type="text/css" rel="stylesheet" href="css/login.css"/>
  7.     </head>
  8.  
  9.     <body>
  10.         <div>
  11.             <form action="LoginMgrController" method="post">
  12.                 <p>
  13.                     账号：<input type="text" name="username"/>
  14.                 </p>
  15.                 <p>
  16.                     密码：<input type="password" name="password"/>
  17.                 </p>
  18.                 <p>
  19.                     <input type="submit" value="登录"/>
  20.                 </p>
  21.             </form>
  22.         </div>
  23.     </body>
  24. </html>

 

7.4.2 login.css

  1. * {
  2.     margin: 0;
  3.     padding: 0;
  4. }
  5.  
  6. div {
  7.     width: 400px;
  8.     background-color: #ccc;
  9.     margin: 30px auto;
  10.     padding-top: 30px;
  11.     text-align: center;
  12. }
  13.  
  14. p {
  15.     margin-top: 10px;
  16. }
  17.  
  18. input {
  19.     outline: none;
  20. }

7.5 LoginMgrController

  1. package com.cxyzxc.www.controller;
  2.  
  3. import com.cxyzxc.www.entity.Manager;
  4. import com.cxyzxc.www.service.ManagerService;
  5. import com.cxyzxc.www.service.impl.ManagerServiceImpl;
  6.  
  7. import javax.servlet.*;
  8. import javax.servlet.http.*;
  9. import javax.servlet.annotation.*;
  10. import java.io.IOException;
  11.  
  12. @WebServlet(name = "LoginMgrController", value = "/LoginMgrController")
  13. public class LoginMgrController extends HttpServlet {
  14.     @Override
  15.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  16.         //1、处理乱码
  17.         request.setCharacterEncoding("UTF-8");
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //2、收参（获取客户端发送过来的请求数据）
  21.         String username = request.getParameter("username");
  22.         String password = request.getParameter("password");
  23.  
  24.         //3、调用业务方法
  25.         ManagerService managerService = new ManagerServiceImpl();
  26.         Manager manager = managerService.login(username, password);
  27.  
  28.  
  29.         //4、处理结果，根据结果做不同的跳转
  30.         if (manager != null) {//manager不为null，说明账号和密码正确，登录成功
  31.             //将获取的账号和密码信息存储在session中
  32.             HttpSession session = request.getSession();
  33.             session.setAttribute("manager", manager);
  34.             //跳转到显示所有管理员信息的Servlet
  35.             response.sendRedirect("/managerProject01_war_exploded/ShowAllManagerController");
  36.         } else {//manager为null。说明账号或者密码错误，登录失败
  37.             response.sendRedirect("/managerProject01_war_exploded/login.html");
  38.         }
  39.  
  40.  
  41.     }
  42.  
  43.     @Override
  44.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  45.         doGet(request, response);
  46.     }
  47. }

7.6 ShowAllManagerController

  1. package com.cxyzxc.www.controller;
  2.  
  3. import com.cxyzxc.www.entity.Manager;
  4. import com.cxyzxc.www.service.ManagerService;
  5. import com.cxyzxc.www.service.impl.ManagerServiceImpl;
  6.  
  7. import javax.servlet.*;
  8. import javax.servlet.http.*;
  9. import javax.servlet.annotation.*;
  10. import java.io.IOException;
  11. import java.util.List;
  12.  
  13. @WebServlet(name = "ShowAllManagerController", value = "/ShowAllManagerController")
  14. public class ShowAllManagerController extends HttpServlet {
  15.     @Override
  16.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  17.         //1、处理乱码
  18.         request.setCharacterEncoding("UTF-8");
  19.         response.setContentType("text/html;charset=UTF-8");
  20.  
  21.         //通过HttpSession完成权限控制
  22.         HttpSession session =request.getSession();
  23.         //获取session中存储的值
  24.         Manager manager = (Manager)session.getAttribute("manager");
  25.         //判断获取的值
  26.         if(manager!=null){
  27.             //调用业务,只做业务，业务与显示分离
  28.             ManagerService managerService = new ManagerServiceImpl();
  29.             List<Manager> managers =managerService.showAllManager();
  30.             //将获取的数据存储在request作用域中
  31.             request.setAttribute("managers",managers);
  32.             //转发，跳转到显示结果的Servlet
  33.             request.getRequestDispatcher("/ShowAllManagerJsp").forward(request,response);
  34.         }else{
  35.             //说明没有登录，要先去登录才能进行显示
  36.             response.sendRedirect("/managerProject01_war_exploded/login.html");
  37.         }
  38.     }
  39.  
  40.     @Override
  41.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  42.         doGet(request, response);
  43.     }
  44. }

7.7 ShowAllManagerJsp

  1. package com.cxyzxc.www.jsp;
  2.  
  3. import com.cxyzxc.www.entity.Manager;
  4.  
  5. import javax.servlet.*;
  6. import javax.servlet.http.*;
  7. import javax.servlet.annotation.*;
  8. import java.io.IOException;
  9. import java.io.PrintWriter;
  10. import java.util.List;
  11.  
  12. @WebServlet(name = "ShowAllManagerJsp", value = "/ShowAllManagerJsp")
  13. public class ShowAllManagerJsp extends HttpServlet {
  14.     @Override
  15.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  16.         //1、处理乱码
  17.         request.setCharacterEncoding("UTF-8");
  18.         response.setContentType("text/html;charset=UTF-8");
  19.  
  20.         //2、获取数据
  21.         List<Manager> managers = (List<Manager>) request.getAttribute("managers");
  22.  
  23.         //获取输出流
  24.         PrintWriter printWriter = response.getWriter();
  25.         if (managers.size() != 0) {
  26.             printWriter.println("<html>");
  27.             printWriter.println("<head>");
  28.             printWriter.println("<title>所有管理员</title>");
  29.             printWriter.println("<link type=\"text/css\" rel=\"stylesheet\" href=\"css/table.css\" />");
  30.             printWriter.println("</head>");
  31.             printWriter.println("<table border='1px' cellspacing='0'>");
  32.             printWriter.println("<tr>");
  33.             printWriter.println(" <th>序号</th>");
  34.             printWriter.println(" <th>账号</th>");
  35.             printWriter.println(" <th>密码</th>");
  36.             printWriter.println(" <th>操作</th>");
  37.             printWriter.println(" </tr>");
  38.             for (int i = 0; i < managers.size(); i++) {
  39.                 printWriter.println("<tr>");
  40.                 printWriter.println("<td>" + (i + 1) + "</td>");
  41.                 printWriter.println("<td>" + managers.get(i).getUsername() + "</td>");
  42.                 printWriter.println("<td>" + managers.get(i).getPassword() + "</td>");
  43.                 printWriter.println("<td><a href=\"#\">修改</a> <a href=\"#\">删除</a></td>");
  44.                 printWriter.println("</tr>");
  45.             }
  46.             printWriter.println("</table>");
  47.             printWriter.println("</html>");
  48.         } else {
  49.             printWriter.println("<h2>数据库中没有数据查询</h2>");
  50.         }
  51.     }
  52.  
  53.     @Override
  54.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  55.         doGet(request, response);
  56.     }
  57. }

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

  1. package com.cxyzxc.www.controller;
  2.  
  3. import cn.dsna.util.images.ValidateCode;
  4.  
  5. import javax.servlet.*;
  6. import javax.servlet.http.*;
  7. import javax.servlet.annotation.*;
  8. import java.io.IOException;
  9.  
  10. /**
  11.  * 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
  12.  */
  13. @WebServlet(name = "VerificationServlet", value = "/VerificationServlet")
  14. public class VerificationServlet extends HttpServlet {
  15.     @Override
  16.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  17.         //设置验证码规格
  18.         ValidateCode validateCode = new ValidateCode(200, 20, 4, 10);
  19.         //获取验证码
  20.         String code = validateCode.getCode();
  21.         //将验证码存储在session中
  22.         HttpSession session = request.getSession();
  23.         session.setAttribute("code",code);
  24.         //将验证码输出到客户端
  25.         validateCode.write(response.getOutputStream());
  26.     }
  27.  
  28.     @Override
  29.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  30.         doGet(request, response);
  31.     }
  32. }

8.2 登录页面

  1. <!DOCTYPE html>
  2. <html lang="en">
  3.     <head>
  4.         <meta charset="UTF-8">
  5.         <title>管理员登录页面</title>
  6.         <link type="text/css" rel="stylesheet" href="css/login.css"/>
  7.     </head>
  8.  
  9.     <body>
  10.         <div>
  11.             <form action="LoginMgrController" method="post">
  12.                 <p>
  13.                     账号：<input type="text" name="username"/>
  14.                 </p>
  15.                 <p>
  16.                     密码：<input type="password" name="password"/>
  17.                 </p>
  18.                 <p>
  19.                     验证码：<input type="text" name="verification"/>
  20.                     <img src="/managerProject02_war_exploded/VerificationServlet" />
  21.                 </p>
  22.                 <p>
  23.                     <input type="submit" value="登录"/>
  24.                 </p>
  25.             </form>
  26.         </div>
  27.     </body>
  28. </html>

8.3 LoginMgrController

  1. package com.cxyzxc.www.controller;
  2.  
  3. import com.cxyzxc.www.entity.Manager;
  4. import com.cxyzxc.www.service.ManagerService;
  5. import com.cxyzxc.www.service.impl.ManagerServiceImpl;
  6.  
  7. import javax.servlet.ServletException;
  8. import javax.servlet.annotation.WebServlet;
  9. import javax.servlet.http.HttpServlet;
  10. import javax.servlet.http.HttpServletRequest;
  11. import javax.servlet.http.HttpServletResponse;
  12. import javax.servlet.http.HttpSession;
  13. import java.io.IOException;
  14.  
  15. @WebServlet(name = "LoginMgrController", value = "/LoginMgrController")
  16. public class LoginMgrController extends HttpServlet {
  17.     @Override
  18.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  19.         //1、处理乱码
  20.         request.setCharacterEncoding("UTF-8");
  21.         response.setContentType("text/html;charset=UTF-8");
  22.  
  23.         //2、收参（获取客户端发送过来的请求数据）
  24.         String username = request.getParameter("username");
  25.         String password = request.getParameter("password");
  26.         String inputCodde = request.getParameter("verification");
  27.  
  28.         //获取session中的验证码
  29.         HttpSession session = request.getSession();
  30.         String codes = (String) session.getAttribute("code");
  31.  
  32.         if (!inputCodde.isEmpty() && inputCodde.equalsIgnoreCase(codes)) {
  33.             //3、调用业务方法
  34.             ManagerService managerService = new ManagerServiceImpl();
  35.             Manager manager = managerService.login(username, password);
  36.  
  37.             //4、处理结果，根据结果做不同的跳转
  38.             if (manager != null) {//manager不为null，说明账号和密码正确，登录成功
  39.                 //将获取的账号和密码信息存储在session中
  40.                 HttpSession session2 = request.getSession();
  41.                 session2.setAttribute("manager", manager);
  42.                 //跳转到显示所有管理员信息的Servlet
  43.                 response.sendRedirect("/managerProject02_war_exploded/ShowAllManagerController");
  44.             } else {//manager为null。说明账号或者密码错误，登录失败
  45.                 response.sendRedirect("/managerProject02_war_exploded/login.html");
  46.             }
  47.         } else {//验证码不对，重新登录
  48.             response.sendRedirect("/managerProject02_war_exploded/login.html");
  49.         }
  50.  
  51.  
  52.     }
  53.  
  54.     @Override
  55.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  56.         doGet(request, response);
  57.     }
  58. }

8.4 ShowAllManagerController

  1. package com.cxyzxc.www.controller;
  2.  
  3. import com.cxyzxc.www.entity.Manager;
  4. import com.cxyzxc.www.service.ManagerService;
  5. import com.cxyzxc.www.service.impl.ManagerServiceImpl;
  6.  
  7. import javax.servlet.ServletException;
  8. import javax.servlet.annotation.WebServlet;
  9. import javax.servlet.http.HttpServlet;
  10. import javax.servlet.http.HttpServletRequest;
  11. import javax.servlet.http.HttpServletResponse;
  12. import javax.servlet.http.HttpSession;
  13. import java.io.IOException;
  14. import java.util.List;
  15.  
  16. @WebServlet(name = "ShowAllManagerController", value = "/ShowAllManagerController")
  17. public class ShowAllManagerController extends HttpServlet {
  18.     @Override
  19.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  20.         //通过HttpSession完成权限控制
  21.         HttpSession session =request.getSession();
  22.         //获取session中存储的值
  23.         Manager manager = (Manager)session.getAttribute("manager");
  24.         //判断获取的值
  25.         if(manager!=null){
  26.             //调用业务,只做业务，业务与显示分离
  27.             ManagerService managerService = new ManagerServiceImpl();
  28.             List<Manager> managers =managerService.showAllManager();
  29.             //将获取的数据存储在request作用域中
  30.             request.setAttribute("managers",managers);
  31.             //转发，跳转到显示结果的Servlet
  32.             request.getRequestDispatcher("/ShowAllManagerJsp").forward(request,response);
  33.         }else{
  34.             //说明没有登录，要先去登录才能进行显示
  35.             response.sendRedirect("/managerProject02_war_exploded/login.html");
  36.         }
  37.     }
  38.  
  39.     @Override
  40.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  41.         doGet(request, response);
  42.     }
  43. }

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