Cookie是一种存储在客户端信息的技术。在上一页中，我们已经了解了很多有关Cookie的技术，例如:如何创建cookie，如何删除cookie，如何获取cookie等。
在这个示例中，我们将使用servlet cookie创建一个登录和注销应用的示例。在此示例中将创建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页面。
启动Eclipse，创建一个动态Web应用项目:LoginServletApp，完整的目录结构如下:
在此应用程序中，需要创建以下几个文件:
- index.html
- link.html
- login.html
- LoginServlet.java
- LogoutServlet.java
- ProfileServlet.java
- web.xml
文件:index.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Servlet登录示例</title> </head> <body> <h1>欢迎使用Cookie登录应用</h1> <a href="login.html">登录</a>| <a href="LogoutServlet">注销</a>| <a href="ProfileServlet">个人信息</a> </body> </html> 文件:link.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <a href="login.html">登录</a>| <a href="LogoutServlet">注销</a>| <a href="ProfileServlet">个人信息</a> <hr> </body> </html> 文件:login.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>登录页面</title> </head> <body> <form action="LoginServlet" method="post"> 用户名:<input type="text" name="name"><br> 密码:<input type="password" name="password"><br> <input type="submit" value="登录"> </form> </body> </html> 文件:LoginServlet.java
package com.xntutor.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoginServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); response.setCharacterEncoding("utf-8"); 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("登录系统成功!"); out.print("<br>您好, " + name); Cookie ck = new Cookie("name", name); response.addCookie(ck); } else { out.print("抱歉，用户名或密码错误!"); request.getRequestDispatcher("login.html").include(request, response); } out.close(); } } 文件:LogoutServlet.java
package com.xntutor.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LogoutServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); response.setCharacterEncoding("utf-8"); PrintWriter out = response.getWriter(); request.getRequestDispatcher("link.html").include(request, response); Cookie ck = new Cookie("name", ""); ck.setMaxAge(0); response.addCookie(ck); out.print("你已经成功注销!"); } } 文件:ProfileServlet.java
package com.xntutor.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ProfileServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); response.setCharacterEncoding("utf-8"); PrintWriter out = response.getWriter(); request.getRequestDispatcher("link.html").include(request, response); Cookie ck[] = request.getCookies(); if (ck != null) { String name = ck[0].getValue(); if (!name.equals("") || name != null) { out.print("<b>欢迎来到个人资料</b>"); out.print("<br>你好, " + name); } } else { out.print("请先登录~"); 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_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>LoginServletApp</display-name> <servlet> <description></description> <display-name>LoginServlet</display-name> <servlet-name>LoginServlet</servlet-name> <servlet-class>com.xntutor.servlet.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>com.xntutor.servlet.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>com.xntutor.servlet.LogoutServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LogoutServlet</servlet-name> <url-pattern>/LogoutServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.html</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> </web-app> 启动Tomcat服务器，打开浏览器访问下面URL:
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/tech/pnotes/264035.html