利用Session完成用户的登录和注销

其他 2019-02-26 08:51:11 阅读次数: 0

用户的登录和注销是最常见的Web应用案例，当一个应用的客户登录了以后，其他所有的会话都得知道这个用户已经登录还很有可能得提取用户的昵称予以显示等等，所以，只有把登录成功的用户的信息放入到Session中才能够办到使所有的Servlet都能访问到用户的登录状态，下面把这个案例放上来。

第一是登录的界面，是HTML的一个表单，非常的简单

[html] view plain copy print ?
  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  2. <html>
  3. <head>
  4. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  5. <title>登陆界面</title>
  6. </head>
  7. <body>
  8. <form action="/Web/servlet/LoginServlet" method="post">
  9. 帐号:<input type="text" name="username"><br>
  10. 密码:<input type="password" name="password"><br>
  11. <input type="submit" value="登录">
  12. </form>
  13. </body>
  14. </html> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登陆界面</title>
</head>
<body>
	<form action="/Web/servlet/LoginServlet" method="post">
	帐号:<input type="text" name="username"><br>
	密码:<input type="password" name="password"><br>
	<input type="submit" value="登录">
	</form>
</body>
</html>

第二是处理登录信息的LoginServlet

[java] view plain copy print ?
  1. package com.bird.login;
  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.util.ArrayList;
  6. import java.util.List;
  8. import javax.servlet.ServletException;
  9. import javax.servlet.http.HttpServlet;
  10. import javax.servlet.http.HttpServletRequest;
  11. import javax.servlet.http.HttpServletResponse;
  13. public class LoginServlet extends HttpServlet {
  15. /**
  16. * @category 使用Session处理用户登陆
  17. * @author Bird
  18. */
  19. private static final long serialVersionUID = 1L;
  21. public void doGet(HttpServletRequest request, HttpServletResponse response)
  22. throws ServletException, IOException {
  23. response.setCharacterEncoding("UTF-8");
  24. response.setContentType("text/html;charset=UTF-8");
  25. PrintWriter out = response.getWriter();
  27. String username = request.getParameter("username");
  28. String password = request.getParameter("password");
  30. List<User> list = Db.getAll();
  31. for(User u: list){
  32. if(u.getUsername().equals(username) && u.getPassword().equals(password)){
  33. request.getSession().setAttribute("user", u);//登录成功，将用户数据放入到Session中
  34. response.sendRedirect("/Web/index.jsp");
  35. return;//进行重定向，并且下面的代码不再执行
  36. }
  37. }
  39. out.write("您的应户名或密码错误");
  40. }
  42. public void doPost(HttpServletRequest request, HttpServletResponse response)
  43. throws ServletException, IOException {
  44. doGet(request,response);
  45. }
  47. }
  49. class Db{
  50. public static List<User> list = new ArrayList<User>();
  51. static{
  52. list.add(new User("aaa","123"));
  53. list.add(new User("bbb","123"));
  54. list.add(new User("ccc","123"));
  55. }
  57. public static List<User> getAll(){
  58. return list;
  59. }
  60. } 
package com.bird.login;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

	/**
	 * @category 使用Session处理用户登陆
	 * @author Bird
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = response.getWriter();
		
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		
		List<User> list = Db.getAll();
		for(User u: list){
			if(u.getUsername().equals(username) && u.getPassword().equals(password)){
				request.getSession().setAttribute("user", u);//登录成功，将用户数据放入到Session中
				response.sendRedirect("/Web/index.jsp");
				return;//进行重定向，并且下面的代码不再执行
			}
		}
		
		out.write("您的应户名或密码错误");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request,response);
	}

}

class Db{
	public static List<User> list = new ArrayList<User>();
	static{
		list.add(new User("aaa","123"));
		list.add(new User("bbb","123"));
		list.add(new User("ccc","123"));
	}
	
	public static List<User> getAll(){
		return list;
	}
}

第三，用户的信息封装在User对象中

[java] view plain copy print ?
  1. package com.bird.login;
  3. /**
  4. * @category 封装用户的数据的对象
  5. * @author Bird
  6. *
  7. */
  8. public class User {
  9. private String username;
  10. private String password;
  13. public User() {
  15. }
  16. public User(String username, String password) {
  18. this.username = username;
  19. this.password = password;
  20. }
  21. public String getUsername() {
  22. return username;
  23. }
  24. public void setUsername(String username) {
  25. this.username = username;
  26. }
  27. public String getPassword() {
  28. return password;
  29. }
  30. public void setPassword(String password) {
  31. this.password = password;
  32. }
  33. } 
package com.bird.login;

/**
 * @category 封装用户的数据的对象
 * @author Bird
 *
 */
public class User {
	private String username;
	private String password;
	
	
	public User() {
		
	}
	public User(String username, String password) {
		
		this.username = username;
		this.password = password;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

第四是处理用户注销的Servlet

[java] view plain copy print ?
  1. package com.bird.login;
  3. import java.io.IOException;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import javax.servlet.http.HttpSession;
  11. public class LoginOutServlet extends HttpServlet {
  13. /**
  14. * @category 退出登录的Servlet,注销
  15. * @author Bird
  16. */
  17. private static final long serialVersionUID = 1L;
  19. public void doGet(HttpServletRequest request, HttpServletResponse response)
  20. throws ServletException, IOException {
  21. HttpSession session = request.getSession(false);//防止创建Session
  22. if(session == null){
  23. response.sendRedirect("/Web/index.jsp");
  24. return;
  25. }
  27. session.removeAttribute("user");
  28. response.sendRedirect("/Web/index.jsp");
  29. }
  31. public void doPost(HttpServletRequest request, HttpServletResponse response)
  32. throws ServletException, IOException {
  34. }
  36. } 
package com.bird.login;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginOutServlet extends HttpServlet {

	/**
	 * @category 退出登录的Servlet,注销
	 * @author Bird
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		HttpSession session = request.getSession(false);//防止创建Session
		if(session == null){
			response.sendRedirect("/Web/index.jsp");
			return;
		}
		
		session.removeAttribute("user");
		response.sendRedirect("/Web/index.jsp");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

}

第五是最终的显示界面

[html] view plain copy print ?
  1. <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
  4. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
  5. <html>
  6. <head>
  9. <title>My JSP 'index.jsp' starting page</title>
  11. </head>
  13. <body>
  14. 欢迎您，${user.username} <br>
  15. <a href="/Web/servlet/LoginOutServlet">退出登录</a>
  16. </body>
  17. </html> 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
   
    
    <title>My JSP 'index.jsp' starting page</title>
	
  </head>
  
  <body>
    欢迎您，${user.username}  <br>
    <a href="/Web/servlet/LoginOutServlet">退出登录</a>
  </body>
</html>

效果如下


登录成功后



注销后



用户的登录和注销是最常见的Web应用案例，当一个应用的客户登录了以后，其他所有的会话都得知道这个用户已经登录还很有可能得提取用户的昵称予以显示等等，所以，只有把登录成功的用户的信息放入到Session中才能够办到使所有的Servlet都能访问到用户的登录状态，下面把这个案例放上来。

第一是登录的界面，是HTML的一个表单，非常的简单

[html] view plain copy print ?
  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  2. <html>
  3. <head>
  4. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  5. <title>登陆界面</title>
  6. </head>
  7. <body>
  8. <form action="/Web/servlet/LoginServlet" method="post">
  9. 帐号:<input type="text" name="username"><br>
  10. 密码:<input type="password" name="password"><br>
  11. <input type="submit" value="登录">
  12. </form>
  13. </body>
  14. </html> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登陆界面</title>
</head>
<body>
	<form action="/Web/servlet/LoginServlet" method="post">
	帐号:<input type="text" name="username"><br>
	密码:<input type="password" name="password"><br>
	<input type="submit" value="登录">
	</form>
</body>
</html>

第二是处理登录信息的LoginServlet

[java] view plain copy print ?
  1. package com.bird.login;
  3. import java.io.IOException;
  4. import java.io.PrintWriter;
  5. import java.util.ArrayList;
  6. import java.util.List;
  8. import javax.servlet.ServletException;
  9. import javax.servlet.http.HttpServlet;
  10. import javax.servlet.http.HttpServletRequest;
  11. import javax.servlet.http.HttpServletResponse;
  13. public class LoginServlet extends HttpServlet {
  15. /**
  16. * @category 使用Session处理用户登陆
  17. * @author Bird
  18. */
  19. private static final long serialVersionUID = 1L;
  21. public void doGet(HttpServletRequest request, HttpServletResponse response)
  22. throws ServletException, IOException {
  23. response.setCharacterEncoding("UTF-8");
  24. response.setContentType("text/html;charset=UTF-8");
  25. PrintWriter out = response.getWriter();
  27. String username = request.getParameter("username");
  28. String password = request.getParameter("password");
  30. List<User> list = Db.getAll();
  31. for(User u: list){
  32. if(u.getUsername().equals(username) && u.getPassword().equals(password)){
  33. request.getSession().setAttribute("user", u);//登录成功，将用户数据放入到Session中
  34. response.sendRedirect("/Web/index.jsp");
  35. return;//进行重定向，并且下面的代码不再执行
  36. }
  37. }
  39. out.write("您的应户名或密码错误");
  40. }
  42. public void doPost(HttpServletRequest request, HttpServletResponse response)
  43. throws ServletException, IOException {
  44. doGet(request,response);
  45. }
  47. }
  49. class Db{
  50. public static List<User> list = new ArrayList<User>();
  51. static{
  52. list.add(new User("aaa","123"));
  53. list.add(new User("bbb","123"));
  54. list.add(new User("ccc","123"));
  55. }
  57. public static List<User> getAll(){
  58. return list;
  59. }
  60. } 
package com.bird.login;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

	/**
	 * @category 使用Session处理用户登陆
	 * @author Bird
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = response.getWriter();
		
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		
		List<User> list = Db.getAll();
		for(User u: list){
			if(u.getUsername().equals(username) && u.getPassword().equals(password)){
				request.getSession().setAttribute("user", u);//登录成功，将用户数据放入到Session中
				response.sendRedirect("/Web/index.jsp");
				return;//进行重定向，并且下面的代码不再执行
			}
		}
		
		out.write("您的应户名或密码错误");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request,response);
	}

}

class Db{
	public static List<User> list = new ArrayList<User>();
	static{
		list.add(new User("aaa","123"));
		list.add(new User("bbb","123"));
		list.add(new User("ccc","123"));
	}
	
	public static List<User> getAll(){
		return list;
	}
}

第三，用户的信息封装在User对象中

[java] view plain copy print ?
  1. package com.bird.login;
  3. /**
  4. * @category 封装用户的数据的对象
  5. * @author Bird
  6. *
  7. */
  8. public class User {
  9. private String username;
  10. private String password;
  13. public User() {
  15. }
  16. public User(String username, String password) {
  18. this.username = username;
  19. this.password = password;
  20. }
  21. public String getUsername() {
  22. return username;
  23. }
  24. public void setUsername(String username) {
  25. this.username = username;
  26. }
  27. public String getPassword() {
  28. return password;
  29. }
  30. public void setPassword(String password) {
  31. this.password = password;
  32. }
  33. } 
package com.bird.login;

/**
 * @category 封装用户的数据的对象
 * @author Bird
 *
 */
public class User {
	private String username;
	private String password;
	
	
	public User() {
		
	}
	public User(String username, String password) {
		
		this.username = username;
		this.password = password;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

第四是处理用户注销的Servlet

[java] view plain copy print ?
  1. package com.bird.login;
  3. import java.io.IOException;
  5. import javax.servlet.ServletException;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import javax.servlet.http.HttpSession;
  11. public class LoginOutServlet extends HttpServlet {
  13. /**
  14. * @category 退出登录的Servlet,注销
  15. * @author Bird
  16. */
  17. private static final long serialVersionUID = 1L;
  19. public void doGet(HttpServletRequest request, HttpServletResponse response)
  20. throws ServletException, IOException {
  21. HttpSession session = request.getSession(false);//防止创建Session
  22. if(session == null){
  23. response.sendRedirect("/Web/index.jsp");
  24. return;
  25. }
  27. session.removeAttribute("user");
  28. response.sendRedirect("/Web/index.jsp");
  29. }
  31. public void doPost(HttpServletRequest request, HttpServletResponse response)
  32. throws ServletException, IOException {
  34. }
  36. } 
package com.bird.login;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginOutServlet extends HttpServlet {

	/**
	 * @category 退出登录的Servlet,注销
	 * @author Bird
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		HttpSession session = request.getSession(false);//防止创建Session
		if(session == null){
			response.sendRedirect("/Web/index.jsp");
			return;
		}
		
		session.removeAttribute("user");
		response.sendRedirect("/Web/index.jsp");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

}

第五是最终的显示界面

[html] view plain copy print ?
  1. <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
  4. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
  5. <html>
  6. <head>
  9. <title>My JSP 'index.jsp' starting page</title>
  11. </head>
  13. <body>
  14. 欢迎您，${user.username} <br>
  15. <a href="/Web/servlet/LoginOutServlet">退出登录</a>
  16. </body>
  17. </html> 
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
   
    
    <title>My JSP 'index.jsp' starting page</title>
	
  </head>
  
  <body>
    欢迎您，${user.username}  <br>
    <a href="/Web/servlet/LoginOutServlet">退出登录</a>
  </body>
</html>

效果如下


登录成功后



注销后



猜你喜欢

转载自blog.csdn.net/xigedanganxi/article/details/11565419
今日推荐
火速冲上 GitHub 热榜 —— 开源编程语言、框架哪有这么可爱？
北京人形机器人创新中心发布全球首个纯电驱拟人奔跑的全尺寸人形机器人“天工”
LFOSSA 源来如此公开课 | 掌握云原生未来：CNCF 认证全面攻略与备考秘籍
国产云输入法——仅华为无云端数据上传安全问题
开源日报 | 工业开源项目OGG 1.0；姐姐，你要和我一起配置火狐吗；苹果AI遥遥落后？Fedora 40
开放签电子签章：停止新增，优化体验，前进更进（五一假期前工作）
周排行
Metasploit文件目录与入侵基本概念
跨域(CORS)请求问题[No 'Access-Control-Allow-Origin' header is present on the requested resource]常见解决方案
CodeIgniter 源码解读之 CodeIgniter.php（二）
SAS入门之（四）改变数据类型
初识元组
[数学建模]数学建模算法和模型（B站视频）（二）
Nginx 服务器源码安装配置流程
C#实现语音视频录制 【基于MCapture + MFile】
开发进度4
下载安装vue的方法网址
每日归档
更多
2024-04-28(0)
2024-04-27(56)
2024-04-26(39)
2024-04-25(22)
2024-04-24(36)
2024-04-23(26)
2024-04-22(39)
2024-04-21(0)
2024-04-20(6)
2024-04-19(5)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022