java web实现自动登录功能_JAVA教程

java web实现自动登录功能

2021-01-23 12:24数星星的咚咚咚 JAVA教程

这篇文章主要为大家详细介绍了java web实现自动登录功能，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了java web实现自动登录功能的具体代码，供大家参考，具体内容如下

主要思路就是：当用户访问网站的首页时，浏览器端会先检擦浏览器中存在的cookie中是否又登录的用户的用户名，如果有，则直接跳转至用户登录好的界面，如果没有，则重定向至登录界面，在服务器端创建该用户登录的cookie,响应时，将创建的cookie返回至浏览器端保存。

一、用户访问首页时检查cookie是否存在。

									package ahpudong.com;

									import java.io.IOException;

									import java.io.PrintWriter;

									import javax.servlet.ServletException;

									import javax.servlet.annotation.WebServlet;

									import javax.servlet.http.Cookie;

									import javax.servlet.http.HttpServlet;

									import javax.servlet.http.HttpServletRequest;

									import javax.servlet.http.HttpServletResponse;

									@WebServlet("/index.do")

									public class index extends HttpServlet {

									 public index() {

									  super();

									 }

									 public void doPost(HttpServletRequest request, HttpServletResponse response)

									   throws ServletException, IOException {

									  Cookie[] cookies=request.getCookies();

									  if(cookies!=null){

									   for(Cookie cookie:cookies){

									    String name=cookie.getName();

									    String value=cookie.getValue();

									    if("name".equals(name) && "chendong".equals(value)){

									     request.setAttribute(name, value);

									     request.getRequestDispatcher("user.view").forward(request, response);

									     return;

									    }

									   } 

									  }

									   response.sendRedirect("login.jsp");

									 }

									}

二、确定用户登录的cookie不存在，在手动登录的过程中创建用户登录cookie。

									package ahpudong.com;

									import java.io.IOException;

									import java.io.PrintWriter;

									import javax.servlet.ServletException;

									import javax.servlet.annotation.WebServlet;

									import javax.servlet.http.Cookie;

									import javax.servlet.http.HttpServlet;

									import javax.servlet.http.HttpServletRequest;

									import javax.servlet.http.HttpServletResponse;

									@WebServlet("/login.do")

									public class login extends HttpServlet {

									 public login() {

									  super();

									 }

									 public void doPost(HttpServletRequest request, HttpServletResponse response)

									   throws ServletException, IOException {

									  response.setContentType("text/html");

									  request.setCharacterEncoding("utf-8");

									  response.setCharacterEncoding("utf-8");

									  PrintWriter out = response.getWriter();

									  String name=request.getParameter("name");

									  String pwd=request.getParameter("pwd");

									  String login=request.getParameter("auto");

									  if("chendong".equals(name) && "123456".equals(pwd)){

									   if("on".equals(login)){

									    Cookie cookie=new Cookie("name","chendong");

									    cookie.setMaxAge(7*24*60*60);//有效期为一个星期

									    response.addCookie(cookie);

									    request.setAttribute("name",name);

									    request.getRequestDispatcher("user.view").forward(request, response);    

									   }

									  }else{

									   response.sendRedirect("login.jsp");

									  }

									 }

									}

三、登录成功时的视图层

									package ahpudong.com;

									import java.io.IOException;

									import java.io.PrintWriter;

									import javax.servlet.ServletException;

									import javax.servlet.annotation.WebServlet;

									import javax.servlet.http.HttpServlet;

									import javax.servlet.http.HttpServletRequest;

									import javax.servlet.http.HttpServletResponse;

									@WebServlet("/user.view")

									public class User extends HttpServlet {

									 public User() {

									  super();

									 }

									 public void doGet(HttpServletRequest request, HttpServletResponse response)

									   throws ServletException, IOException {

									  processRequest(request,response);

									 }

									 public void doPost(HttpServletRequest request, HttpServletResponse response)

									   throws ServletException, IOException {

									  processRequest(request,response);

									 }

									 public void processRequest(HttpServletRequest request,HttpServletResponse response)

									   throws ServletException, IOException{

									  response.setCharacterEncoding("utf-8");

									  PrintWriter out=response.getWriter();

									  String name=(String) request.getAttribute("name");

									  out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");

									  out.println("<HTML>");

									  out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");

									  out.println(" <BODY>");

									  out.println("<h1>"+"welcome "+name+" login"+"</h1>");

									  out.println(" </BODY>");

									  out.println("</HTML>");

									  out.flush();

									  out.close(); 

									 }

									}