Cookie技术

CookieOne.java

package com.cookie;

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;

/**
 * Servlet implementation class CookieOne
 */
@WebServlet("/CookieOne")
public class CookieOne extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CookieOne() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //创建一个cookie(api)
        Cookie cookie=new Cookie("name","xiaomi");
        //设置cookie的生命周期
        cookie.setMaxAge(3600);///3600秒一个小时
        //把cookie信息写给浏览器
        response.addCookie(cookie);
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

ReadCookie.java

package com.cookie;

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

/**
 * Servlet implementation class ReadCookie
 */
@WebServlet("/ReadCookie")
public class ReadCookie extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ReadCookie() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //读取所有cookie信息，选取
        Cookie cookies[]=request.getCookies();
        System.out.println(cookies.length);
        //遍历cookie
        for(int i=0;i<cookies.length;i++){
            Cookie  cookie=cookies[i];
            out.println("cookie的信息 Name=："+cookie.getName()+"Value="+cookie.getValue());
            out.println();
            
        }
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

MD5加密后再进行数据库访问

MD5算法'

package com.cookie;

public class MD5 {

        public static String getMD5(byte[] source) {
            String s = null;
            char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9','a',
                    'b','c','d','e','f'};
            try {
                java.security.MessageDigest md = 
                        java.security.MessageDigest.getInstance("MD5");
                md.update(source);
                byte tmp[] = md.digest();
                char str[] = new char[16*2];
                int k = 0;
                for (int i = 0; i < 16; i++) {
                    byte byte0 = tmp[i];
                    str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                    str[k++] = hexDigits[byte0 & 0xf];
                }
                s = new String(str);
            } catch(Exception e) {
                e.printStackTrace();
            }
            return s;
        }
         
        public static void main(String[] args) {
            String a = "I love you";
            byte[] b = a.getBytes();
            for (int i=0; i<b.length; i++)
                System.out.print(b[i] + " ");
            String str = MD5.getMD5(b);
            System.out.println("a = " + a + "
" + "str = " + str + "
");
    
        }
}

View Code

实例：写出你上次登录时间

package com.cook;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;

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;

/**
 * Servlet implementation class CookieOne
 */
@WebServlet("/CookieOne")
public class CookieOne extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CookieOne() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        Cookie []cookies=request.getCookies();
        //保存上次登录的Cookie lasttime
        boolean b=false;
        if(cookies!=null){
        for(Cookie cookie:cookies){
            //取出名字
            String name=cookie.getName();
            if(name.equals("lasttime")){
                out.print("你上次登陆的时间："+cookie.getValue());
                //更新时间
                  SimpleDateFormat myFmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                     String nowTime= myFmt.format(new java.util.Date());
                Cookie mycookie1=new Cookie("lasttime",nowTime);
                mycookie1.setMaxAge(7*3600*24);
                response.addCookie(mycookie1);
                
                b=true;
                break;
            }
        }}
        
        if(!b){
            out.print("你是第一次登录");
            //吧当前的日期保存到Cookie
              SimpleDateFormat myFmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
             String nowTime= myFmt.format(new java.util.Date());
        Cookie cookie1=new Cookie("lasttime",nowTime);
        cookie1.setMaxAge(7*3600*24);
        response.addCookie(cookie1);
        
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

优化后的代码：

package com.cook;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;

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;

/**
 * Servlet implementation class CookieOne
 */
@WebServlet("/CookieOne")
public class CookieOne extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CookieOne() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        Cookie []cookies=request.getCookies();
        //保存上次登录的Cookie lasttime
        boolean b=false;
        if(cookies!=null){
        for(Cookie cookie:cookies){
            //取出名字
            String name=cookie.getName();
            if(name.equals("lasttime")){
                out.print("你上次登陆的时间："+cookie.getValue());
                //更新时间
                  SimpleDateFormat myFmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                     String nowTime= myFmt.format(new java.util.Date());
                cookie.setValue(nowTime);
                cookie.setMaxAge(7*3600*24);
                response.addCookie(cookie);
                
                b=true;
                break;
            }
        }}
        
        if(!b){
            out.print("你是第一次登录");
            //吧当前的日期保存到Cookie
              SimpleDateFormat myFmt=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
             String nowTime= myFmt.format(new java.util.Date());
        Cookie cookie1=new Cookie("lasttime",nowTime);
        cookie1.setMaxAge(7*3600*24);
        response.addCookie(cookie1);
        
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

打开登录页面，自动填写用户名与密码

LoinServlet.java

package com.view;

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;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //从Cookie中选出
        String id="";
        Cookie cookies[]=request.getCookies();
        if(cookies!=null){
        for(Cookie cookie:cookies){
            if(cookie.getName().equals("id")){
                id=cookie.getValue();
            }
        }
        }
        out.println("<h1>用户登录</h1>");
        out.println("<form action='/Cook/LoginCL' method='post'>");
        out.println("用户id:<input type='text' name='id' value='"+id+"'></br>");
        out.println("密 码:<input type='password' name='password'></br>");
        out.print("<input type='checkbox' value='keep' name='keepinfo'/>在此电脑上保存<br/>");
        out.println("<input type='submit' value='登录' '></br>");
        out.println("</form>");
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

LoginCL.java

package com.Control;


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;

/**
 * Servlet implementation class LoginCL
 */
@WebServlet("/LoginCL")
public class LoginCL extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginCL() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //判断有没有选择
        String val=request.getParameter("keepinfo");
        String id=request.getParameter("id");
        String passwors =request.getParameter("password");
        if(val!=null&&val.equals("keep")){
            //包含该用户 创建cooie并保存到
            Cookie cookie=new Cookie("id",id);
            cookie.setMaxAge(7*24*3600);
            //回写
            response.addCookie(cookie);
            request.getRequestDispatcher("/ok").forward(request, response);
        }else {
            request.getRequestDispatcher("/ok").forward(request, response);    
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

package com.view;

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;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //从Cookie中选出
        String id="";
        Cookie cookies[]=request.getCookies();
        if(cookies!=null){
        for(Cookie cookie:cookies){
            if(cookie.getName().equals("id")){
                id=cookie.getValue();
            }
        }
        }
        out.println("<h1>用户登录</h1>");
        out.println("<form action='/Cook/LoginCL' method='post'>");
        out.println("用户id:<input type='text' name='id' value='"+id+"'></br>");
        out.println("密 码:<input type='password' name='password'></br>");
        out.print("<input type='checkbox' value='keep' name='keepinfo'/>在此电脑上保存<br/>");
        out.print("<input type='checkbox' value='nokeep' name='keepinfo'/>不想在此电脑上保存<br/>");
        out.println("<input type='submit' value='登录' '></br>");
        out.println("</form>");
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

package com.Control;


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;

/**
 * Servlet implementation class LoginCL
 */
@WebServlet("/LoginCL")
public class LoginCL extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginCL() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //判断有没有选择
        String val=request.getParameter("keepinfo");
        String id=request.getParameter("id");
        String passwors =request.getParameter("password");
        if(val!=null&&val.equals("keep")){
            //包含该用户 创建cooie并保存到
            Cookie cookie=new Cookie("id",id);
            cookie.setMaxAge(7*24*3600);
            //回写
            response.addCookie(cookie);
            request.getRequestDispatcher("/ok").forward(request, response);
        }else  if(val!=null&&val.equals("nokeep")){
            Cookie cookies[]=request.getCookies();
            for(Cookie cookie:cookies){
                if(cookie.getName().equals("id")){
                    cookie.setMaxAge(0);
                    response.addCookie(cookie);
                }
            }
            }
            
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

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原文地址：https://www.cnblogs.com/helloworld2019/p/11032651.html