Session案例-用户登录场景
2024-10-06 23:39:36
package com.loaderman.demo; import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* 用户主页的逻辑
*
*/
public class IndexServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter writer = response.getWriter();
String html = "";
/**
* 接收request域对象的数据
*/
/*
String loginName = (String)request.getAttribute("loginName");
*/
/**
* 二、在用户主页,判断session不为空且存在指定的属性才视为登录成功!才能访问资源。
* 从session域中获取会话数据
*/
//1.得到session对象
HttpSession session = request.getSession(false);
if(session==null){
//没有登录成功,跳转到登录页面
response.sendRedirect(request.getContextPath()+"/login.html");
return;
}
//2.取出会话数据
String loginName = (String)session.getAttribute("loginName");
if(loginName==null){
//没有登录成功,跳转到登录页面
response.sendRedirect(request.getContextPath()+"/login.html");
return;
}
html = "<html><body>欢迎回来,"+loginName+",<a href='"+request.getContextPath()+"/logout'>安全退出</a></body></html>";
writer.write(html);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
} }
package com.loaderman.demo; 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;
/**
* 处理登录的逻辑
* @author APPle
*
*/
public class LoginServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
//1.接收参数
String userName = request.getParameter("userName");
String userPwd = request.getParameter("userPwd"); //2.判断逻辑
if("admin".equals(userName)
&& "123456".equals(userPwd)){
//登录成功
/**
* 分析:
* context域对象:不合适,可能会覆盖数据。
* request域对象: 不合适,整个网站必须得使用转发技术来跳转页面
* session域对象:合适。
*/
/*
request.setAttribute("loginName", userName);
//request.getRequestDispatcher("/IndexServlet").forward(request, response);
response.sendRedirect(request.getContextPath()+"/IndexServlet");
*/ /**
* 一、登录成功后,把用户数据保存session对象中
*/
//1.创建session对象
HttpSession session = request.getSession();
//2.把数据保存到session域中
session.setAttribute("loginName", userName);
//3.跳转到用户主页
response.sendRedirect(request.getContextPath()+"/index"); }else{
//登录失败
//请求重定向
response.sendRedirect(request.getContextPath()+"/fail.html");
}
} public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
} }
package com.loaderman.demo; 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;
/**
* 退出逻辑
*
*/
public class LogoutServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
/**
* 三、安全退出:
* 删除掉session对象中指定的loginName属性即可!
*/
//1.得到session对象
HttpSession session = request.getSession(false);
if(session!=null){
//2.删除属性
session.removeAttribute("loginName");
}
//2.回来登录页面
response.sendRedirect(request.getContextPath()+"/login.html");
} public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
web.xml配置:
<servlet>
<!-- servlet的内部名称,自定义。尽量有意义 -->
<servlet-name>IndexServlet</servlet-name>
<!-- servlet的类全名: 包名+简单类名 -->
<servlet-class>com.loaderman.demo.IndexServlet</servlet-class>
</servlet> <servlet-mapping>
<!-- servlet的内部名称,一定要和上面的内部名称保持一致!! -->
<servlet-name>IndexServlet</servlet-name>
<!-- servlet的映射路径(访问servlet的名称) -->
<url-pattern>/index</url-pattern>
</servlet-mapping>
<servlet>
<!-- servlet的内部名称,自定义。尽量有意义 -->
<servlet-name>LoginServlet</servlet-name>
<!-- servlet的类全名: 包名+简单类名 -->
<servlet-class>com.loaderman.demo.LoginServlet</servlet-class>
</servlet> <servlet-mapping>
<!-- servlet的内部名称,一定要和上面的内部名称保持一致!! -->
<servlet-name>LoginServlet</servlet-name>
<!-- servlet的映射路径(访问servlet的名称) -->
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet>
<!-- servlet的内部名称,自定义。尽量有意义 -->
<servlet-name>LogoutServlet</servlet-name>
<!-- servlet的类全名: 包名+简单类名 -->
<servlet-class>com.loaderman.demo.LogoutServlet</servlet-class>
</servlet> <servlet-mapping>
<!-- servlet的内部名称,一定要和上面的内部名称保持一致!! -->
<servlet-name>LogoutServlet</servlet-name>
<!-- servlet的映射路径(访问servlet的名称) -->
<url-pattern>/logout</url-pattern>
</servlet-mapping>
fail.xml
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>信息提示页面</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body>
<font color='red' size='3'>亲, 你的用户名或密码输入有误!请重新输入!</font><br/>
<a href="/login.html">返回登录页面</a>
</body>
</html>
login.xml
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>登录页面</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body>
<form action="/login" method="post">
用户名:<input type="text" name="userName"/>
<br/>
密码:<input type="text" name="userPwd"/>
<br/>
<input type="submit" value="登录"/>
</form>
</body>
</html>
ok ,运行服务器,访问index,就可以模拟实现用户登录了~~~
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