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項目目錄

package com.yuanze.servlet;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;


import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
 
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.yuanze.bean.Person;
import com.yuanze.dao.Dao;
import com.yuanze.util.MD5Util;

public class LoginServlet extends HttpServlet {
    
    public static
 
 Log log = LogFactory.getLog(LoginServlet.class);
    
    
    public void setCookie(HttpServletResponse resp,String zh,String ssid,int timeout) {
        Cookie zhCookie=new Cookie("zh",zh);
        zhCookie.setMaxAge(timeout);
        
        Cookie ssidCookie=new Cookie("ssid",ssid);
        ssidCookie.setMaxAge(timeout);
        
        resp.addCookie(zhCookie);
        resp.addCookie(ssidCookie);
    }
    
    
    @Override
    
 
public void init() throws ServletException {
        // TODO Auto-generated method stub
        super.init();
        List<Person> l=new ArrayList<>();
        l.add(new Person("root","admin"));
        l.add(new Person("123","123"));
        try {
            Dao.Insertdata(l);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub

        String action=req.getParameter("action");

        if(action!=null) {
            if(action.equals("login")) {
                String zh=req.getParameter("zh");
                String mm=req.getParameter("mm");
                int timeout=new Integer(req.getParameter("timeout"));
                
                log.info("賬號:"+zh);
                log.info("密碼:"+mm);
                log.info("timeout:"+timeout);
                
                String info=null;
                try {
                    List<Person> l=Dao.Selectdata(zh);
                    if(l.size()==0) {
                            info="該用戶不存在";
                    }
                    else {
                        if(l.get(0).getMm().equals(mm)) {
                            info="登錄成功";
                            
                            String ssid=MD5Util.calcMD5(zh+MD5Util.KEY);
                            setCookie(resp, zh, ssid, timeout);
                            
                            resp.sendRedirect(req.getContextPath()+"/"+"login"+"?"+System.currentTimeMillis());
                            return;
                            
                        }
                        else {
                            info="密碼錯誤";
                        }
                    }
                    
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    info=e.getMessage();
                }
                log.info(info);
                req.getSession(true).setAttribute("info",info);

            }
            else if (action.equals("logout")) {
                setCookie(resp, "", "", 0);
                resp.sendRedirect(req.getContextPath()+"/"+"login"+"?"+System.currentTimeMillis());
                return;
            }
        }
        
        
        
        
        
        
        boolean login=false;
        String account=null;
        String ssid=null;
        
        if(req.getCookies()!=null) {
            int x=0;
            for(Cookie cookie:req.getCookies()) {
                if(cookie.getName().equals("zh"))
                    account =cookie.getValue();
                
                if(cookie.getName().equals("ssid"))
                    ssid =cookie.getValue();
                
                log.info("cookie"+String.valueOf(++x)+":"+cookie.getValue());
                
                
            }
        }
        
        
        
        
        if(account !=null &&ssid!=null) {
            
            log.info("ssid"+ssid);
            log.info("md5"+MD5Util.calcMD5(account+MD5Util.KEY));
            
            login =ssid.equals(MD5Util.calcMD5(account+MD5Util.KEY));
        }
        log.info(login);
        req.getSession(true).setAttribute("login",login);
        req.getRequestDispatcher("/login.jsp").forward(req, resp);
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(req, resp);
    }

    
}

package com.yuanze.util;
import java.security.MessageDigest;

public class MD5Util {
    public static final String KEY=":[email protected]";
    public final static String calcMD5(String ss) {
        String s=  ss==null ? "":ss;
        char hexDigits[] = {‘0‘,‘1‘,‘2‘,‘3‘,‘4‘,‘5‘,‘6‘,‘7‘,‘8‘,‘9‘,‘a‘,‘b‘,‘c‘,‘d‘,‘e‘,‘f‘};
        try {
            byte[] strTemp=s.getBytes();
            MessageDigest mdTemp=MessageDigest.getInstance("MD5");
            mdTemp.update(strTemp);
            byte[] md=mdTemp.digest();
            int j=md.length;
            char str[]=new char[j*2];
            int k=0;
            for(int i=0;i<j;i++) {
                byte byte0=md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
         }catch(Exception e) {
            return null;
        }
    }
}

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">

</head>
<body>

<%
    String info=String.valueOf(request.getSession().getAttribute("info"));
    request.getSession().removeAttribute("info");
    boolean login=String.valueOf(request.getSession().getAttribute("login")).equals("true")?true:false;
    request.getSession().removeAttribute("login");
%>

<legend><%=login? "歡迎回來":"請先登錄" %></legend>

<% if(login){%>

歡迎你,${ cookie.zh.value } . &nbsp;&nbsp;
<a href="login?action=logout">註銷</a>
<%}else{ %>

<legend><%=info.equals("null")?"":info%></legend>

<form action="login?action=login" method="POST">
<table>
            <tr>
            <td> 賬號:</td>
            <td><input type="text" name="zh" style="width:200px"></td>
            </tr>
            <tr>
            <td> 密碼:</td>
            <td><input type="text" name="mm"></td>
            </tr>

<tr>
<td> 登錄有效期</td>
<td>
    <input type="radio" name="timeout"  value="-1" checked="checked">關閉瀏覽器失效<br>
    <input type="radio" name="timeout"  value="<%= 30*24*60*60 %>" >30天<br>
    <input type="radio" name="timeout"  value="<%=Integer.MAX_VALUE %>">永久有效<br>
</td>
</tr>

<tr>
<td>
<input type="submit" value="登錄" class="button">
</td>
</tr>

</table>


</form>

<%} %>

</body>
</html>

其他文件參考

Servlet二

Servlet一

實現思路:

cookie的存活期 是通過 服務器 response對象中cookie設置實現的，添加cookie對象，並設置時間，-1代表 退出瀏覽器即失效，0代表只用於本次請求，正數值代表存活秒數，正無窮大代表 永久

退出登錄的實現 設置同名 cookie 並設置 timeout 為 0

鏈接：https://pan.baidu.com/s/15sstGWAHlbZEQNg3TT2A7g
提取碼：m7mw

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