srcmini我们可以将对象绑定到HttpSession实例上, 并使用setAttribute和getAttribute方法获取对象。
在上一页中, 我们了解了什么是HttpSession, 如何从会话对象存储和获取数据等。
在这里, 我们将创建一个不使用数据库代码的真实的登录和注销应用程序。我们假设密码为admin123。
访问此处以获取仅使用cookie的登录和注销应用程序使用cookie的servlet登录和注销示例
在此示例中, 我们将创建3个链接：登录, 注销和配置文件。用户必须先登录才能进入个人资料页面。如果用户已注销, 则需要再次登录才能访问个人资料。
在此应用程序中, 我们创建了以下文件。
- index.html
- link.html
- login.html
- LoginServlet.java
- LogoutServlet.java
- ProfileServlet.java
- web.xml
档案：index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Servlet Login Example</title>
</head>
<body>
<h1>Login App using HttpSession</h1>
<a href="login.html">Login</a>|
<a href="LogoutServlet">Logout</a>|
<a href="ProfileServlet">Profile</a>
</body>
</html>档案：link.html
<a href="login.html">Login</a> |
<a href="LogoutServlet">Logout</a> |
<a href="ProfileServlet">Profile</a>
<hr>档案：login.html
<form action="LoginServlet" method="post">
Name:<input type="text" name="name"><br>
Password:<input type="password" name="password"><br>
<input type="submit" value="login">
</form>文件：LoginServlet.java
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;
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
String name=request.getParameter("name");
String password=request.getParameter("password");
if(password.equals("admin123")){
out.print("Welcome, "+name);
HttpSession session=request.getSession();
session.setAttribute("name", name);
}
else{
out.print("Sorry, username or password error!");
request.getRequestDispatcher("login.html").include(request, response);
}
out.close();
}
}文件：LogoutServlet.java
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;
public class LogoutServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
HttpSession session=request.getSession();
session.invalidate();
out.print("You are successfully logged out!");
out.close();
}
}文件：ProfileServlet.java
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;
public class ProfileServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out=response.getWriter();
request.getRequestDispatcher("link.html").include(request, response);
HttpSession session=request.getSession(false);
if(session!=null){
String name=(String)session.getAttribute("name");
out.print("Hello, "+name+" Welcome to Profile");
}
else{
out.print("Please login first");
request.getRequestDispatcher("login.html").include(request, response);
}
out.close();
}
}文件：web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<servlet>
<description></description>
<display-name>LoginServlet</display-name>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>ProfileServlet</display-name>
<servlet-name>ProfileServlet</servlet-name>
<servlet-class>ProfileServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ProfileServlet</servlet-name>
<url-pattern>/ProfileServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>LogoutServlet</display-name>
<servlet-name>LogoutServlet</servlet-name>
<servlet-class>LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LogoutServlet</servlet-name>
<url-pattern>/LogoutServlet</url-pattern>
</servlet-mapping>
</web-app>下载此示例(使用Eclipse IDE开发)
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