java web實現(xiàn)自動登錄功能

更新時間：2021年08月15日 10:29:01 作者：數(shù)星星的咚咚咚

這篇文章主要為大家詳細(xì)介紹了java web實現(xiàn)自動登錄功能，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了java web實現(xiàn)自動登錄功能的具體代碼，供大家參考，具體內(nèi)容如下

主要思路就是：當(dāng)用戶訪問網(wǎng)站的首頁時，瀏覽器端會先檢擦瀏覽器中存在的cookie中是否又登錄的用戶的用戶名，如果有，則直接跳轉(zhuǎn)至用戶登錄好的界面，如果沒有，則重定向至登錄界面，在服務(wù)器端創(chuàng)建該用戶登錄的cookie,響應(yīng)時，將創(chuàng)建的cookie返回至瀏覽器端保存。

一、用戶訪問首頁時檢查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、確定用戶登錄的cookie不存在，在手動登錄的過程中創(chuàng)建用戶登錄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);//有效期為一個星期
    response.addCookie(cookie);
    request.setAttribute("name",name);
    request.getRequestDispatcher("user.view").forward(request, response);    
   }
  }else{
   response.sendRedirect("login.jsp");
  }
 }
}

三、登錄成功時的視圖層

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(); 
 }
}

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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