实现手机扫描二维码进行登录

项目结构：

实现流程：

pc端：

1:打开二维码登录网页index.html

2:index.html调用GetQrCodeServlet

3:GetQrCodeServlet干2件事

　　a:生成随机的uuid,是一个唯一标识，该标识贯穿整个流程

　　b:生成二维码图片，二维码信息：http://xx.xx.xx.xx:8080/QrCodeLoginPro/Login.html?uuid=" + uuid

4:index页面展示二维码

5:index页面调用LongConnectionCheckServlet进行长连接轮询操作，参数为uuid

6:LongConnectionCheckServlet只干1件事

　　a:拿到uuid后循环检查loginUserMap中uuid是否不为null。

7:如果为null则代表没有登录，index.html将继续进行轮询

　　ps: LongConnectionCheckServlet 一个长连接请求检测登录状态

　　　　loginUserMap 是一个静态的map结构的登录池，uuid为key , 登录信息为value

手机端：

1:扫描pc端的二维码

2:打开二维码中的网页 http://xx.xx.xx.xx:8380/QrCodeLoginPro/Login.html?uuid=" + uuid

3:登录，将uname upwd uuid 传递给登录程序PhoneLoginServlet

4:PhoneLoginServlet干2件事

　　a:检测登录

　　b:登录成功后将登录信息插入到loginUserMap中去，uuid为key

pc端：

　　1:继续轮询检测uuid中是否为null

　　2:登录后的uuid中就不为null了，此时LongConnectionCheckServlet停止循环，返回登录状态。

代码：

cn.kuwo下的3个servlet

package cn.kuwo;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.kuwo.util.TwoDimensionCode;

/**
 * 生成二维码图片以及uuid
 * @author zijuntang
 *
 */
public class GetQrCodeServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        
        //生成唯一ID
        int uuid = (int) (Math.random() * 100000);
        //二维码内容
        String content = "http://xx.xx.xx.xx:8380/QrCodeLoginPro/Login.html?uuid=" + uuid;
        //生成二维码
        String imgName =  uuid + "_" + (int) (new Date().getTime() / 1000) + ".png";
        String imgPath = "/home/web/apache/htdocs/QrCodeLogin/" + imgName;
        TwoDimensionCode handler = new TwoDimensionCode();
        handler.encoderQRCode(content, imgPath, "png");
        
        //生成的图片访问地址
        String qrCodeImg = "http://xx.xx.xx.xx/QrCodeLogin/" + imgName;
        String jsonStr = "{"uuid":" + uuid + ","qrCodeImg":"" + qrCodeImg + ""}";
        out.print(jsonStr);
        out.flush();
        out.close();
    }
}
package cn.kuwo;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.kuwo.vo.LoginUserVo;
import cn.kuwo.vo.UserVo;

/**
 * 用长连接，检查登录状态
 * @author zijuntang
 *
 */
public class LongConnectionCheckServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String uuid = request.getParameter("uuid");
        String jsonStr = "";
        System.out.println("in");
        System.out.println("uuid:" + uuid);
        long inTime = new Date().getTime();
        Boolean bool = true;
        while (bool) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            //检测登录
            UserVo userVo = LoginUserVo.getLoginUserMap().get(uuid);
            System.out.println("userVo:" + userVo);
            if(userVo != null){
                bool = false;
                jsonStr = "{"uname":""+userVo.getUname()+""}";
                LoginUserVo.getLoginUserMap().remove(uuid);
            }else{
                if(new Date().getTime() - inTime > 5000){
                    bool = false;
                }
            }
        }
        System.out.println("login ok : " + jsonStr);
        PrintWriter out = response.getWriter();
        out.print(jsonStr);
        out.flush();
        out.close();
    }
}
package cn.kuwo;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.kuwo.vo.LoginUserVo;
import cn.kuwo.vo.UserVo;

/**
 * 二维码手机端登录
 * @author zijuntang
 *
 */
public class PhoneLoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public PhoneLoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String uuid = request.getParameter("uuid");
        String uname = request.getParameter("uname");
        String upwd = request.getParameter("upwd");
        System.out.println(uuid);
        System.out.println(uname);
        System.out.println(upwd);
        //TODO 验证登录
        boolean bool = true;
        if(bool){
            //将登陆信息存入map
            UserVo userVo = LoginUserVo.getLoginUserMap().get(uuid);
            if(userVo == null){
                userVo = new UserVo();
                userVo.setUname(uname);
                userVo.setUpwd(upwd);
                LoginUserVo.getLoginUserMap().put(uuid, userVo);
            }
        }
        PrintWriter out = response.getWriter();
        out.print(bool);
        out.flush();
        out.close();
    }
}

cn.kuwo.util包下的生成二维码的封装类

package cn.kuwo.util;  
  
import java.awt.Color;  
import java.awt.Graphics2D;  
import java.awt.image.BufferedImage;  
import java.io.File;  
import java.io.IOException;  
import java.io.InputStream;  
import java.io.OutputStream;  
import javax.imageio.ImageIO;  
import jp.sourceforge.qrcode.QRCodeDecoder;  
import jp.sourceforge.qrcode.exception.DecodingFailedException;  
import com.swetake.util.Qrcode;  
  
public class TwoDimensionCode {  
      
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param imgPath 图片路径 
     */  
    public void encoderQRCode(String content, String imgPath) {  
        this.encoderQRCode(content, imgPath, "png", 7);  
    }  
      
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param output 输出流 
     */  
    public void encoderQRCode(String content, OutputStream output) {  
        this.encoderQRCode(content, output, "png", 7);  
    }  
      
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param imgPath 图片路径 
     * @param imgType 图片类型 
     */  
    public void encoderQRCode(String content, String imgPath, String imgType) {  
        this.encoderQRCode(content, imgPath, imgType, 7);  
    }  
      
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param output 输出流 
     * @param imgType 图片类型 
     */  
    public void encoderQRCode(String content, OutputStream output, String imgType) {  
        this.encoderQRCode(content, output, imgType, 7);  
    }  
  
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param imgPath 图片路径 
     * @param imgType 图片类型 
     * @param size 二维码尺寸 
     */  
    public void encoderQRCode(String content, String imgPath, String imgType, int size) {  
        try {  
            BufferedImage bufImg = this.qRCodeCommon(content, imgType, size);  
              
            File imgFile = new File(imgPath);
            if (!imgFile.exists())
            {
                imgFile.mkdirs();
            }
            // 生成二维码QRCode图片  
            ImageIO.write(bufImg, imgType, imgFile);  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
  
    /** 
     * 生成二维码(QRCode)图片 
     * @param content 存储内容 
     * @param output 输出流 
     * @param imgType 图片类型 
     * @param size 二维码尺寸 
     */  
    public void encoderQRCode(String content, OutputStream output, String imgType, int size) {  
        try {  
            BufferedImage bufImg = this.qRCodeCommon(content, imgType, size);  
            // 生成二维码QRCode图片  
            ImageIO.write(bufImg, imgType, output);  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
      
    /** 
     * 生成二维码(QRCode)图片的公共方法 
     * @param content 存储内容 
     * @param imgType 图片类型 
     * @param size 二维码尺寸 
     * @return 
     */  
    private BufferedImage qRCodeCommon(String content, String imgType, int size) {  
        BufferedImage bufImg = null;  
        try {  
            Qrcode qrcodeHandler = new Qrcode();  
            // 设置二维码排错率，可选L(7%)、M(15%)、Q(25%)、H(30%)，排错率越高可存储的信息越少，但对二维码清晰度的要求越小  
            qrcodeHandler.setQrcodeErrorCorrect('M');  
            qrcodeHandler.setQrcodeEncodeMode('B');  
            // 设置设置二维码尺寸，取值范围1-40，值越大尺寸越大，可存储的信息越大  
            qrcodeHandler.setQrcodeVersion(size);  
            // 获得内容的字节数组，设置编码格式  
            byte[] contentBytes = content.getBytes("utf-8");  
            // 图片尺寸  
            int imgSize = 67 + 12 * (size - 1);  
            bufImg = new BufferedImage(imgSize, imgSize, BufferedImage.TYPE_INT_RGB);  
            Graphics2D gs = bufImg.createGraphics();  
            // 设置背景颜色  
            gs.setBackground(Color.WHITE);  
            gs.clearRect(0, 0, imgSize, imgSize);  
  
            // 设定图像颜色> BLACK  
            gs.setColor(Color.BLACK);  
            // 设置偏移量，不设置可能导致解析出错  
            int pixoff = 2;  
            // 输出内容> 二维码  
            if (contentBytes.length > 0 && contentBytes.length < 800) {  
                boolean[][] codeOut = qrcodeHandler.calQrcode(contentBytes);  
                for (int i = 0; i < codeOut.length; i++) {  
                    for (int j = 0; j < codeOut.length; j++) {  
                        if (codeOut[j][i]) {  
                            gs.fillRect(j * 3 + pixoff, i * 3 + pixoff, 3, 3);  
                        }  
                    }  
                }  
            } else {  
                throw new Exception("QRCode content bytes length = " + contentBytes.length + " not in [0, 800].");  
            }  
            gs.dispose();  
            bufImg.flush();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        return bufImg;  
    }  
      
    /** 
     * 解析二维码（QRCode） 
     * @param imgPath 图片路径 
     * @return 
     */  
    public String decoderQRCode(String imgPath) {  
        // QRCode 二维码图片的文件  
        File imageFile = new File(imgPath);  
        BufferedImage bufImg = null;  
        String content = null;  
        try {  
            bufImg = ImageIO.read(imageFile);  
            QRCodeDecoder decoder = new QRCodeDecoder();  
            content = new String(decoder.decode(new TwoDimensionCodeImage(bufImg)), "utf-8");   
        } catch (IOException e) {  
            System.out.println("Error: " + e.getMessage());  
            e.printStackTrace();  
        } catch (DecodingFailedException dfe) {  
            System.out.println("Error: " + dfe.getMessage());  
            dfe.printStackTrace();  
        }  
        return content;  
    }  
      
    /** 
     * 解析二维码（QRCode） 
     * @param input 输入流 
     * @return 
     */  
    public String decoderQRCode(InputStream input) {  
        BufferedImage bufImg = null;  
        String content = null;  
        try {  
            bufImg = ImageIO.read(input);  
            QRCodeDecoder decoder = new QRCodeDecoder();  
            content = new String(decoder.decode(new TwoDimensionCodeImage(bufImg)), "utf-8");   
        } catch (IOException e) {  
            System.out.println("Error: " + e.getMessage());  
            e.printStackTrace();  
        } catch (DecodingFailedException dfe) {  
            System.out.println("Error: " + dfe.getMessage());  
            dfe.printStackTrace();  
        }  
        return content;  
    }  
  
    public static void main(String[] args) {  
        String imgPath = "D:/aaa/Michael_QRCode.png";  
        String encoderContent = "http://xx.xx.xx.xx:8380/QrCodeLoginPro/Login.html";  
        TwoDimensionCode handler = new TwoDimensionCode();  
        handler.encoderQRCode(encoderContent, imgPath, "png");
        
        
        /*
        System.out.println("========encoder success");  
        String decoderContent = handler.decoderQRCode(imgPath);  
        System.out.println("解析结果如下：");  
        System.out.println(decoderContent);  
        System.out.println("========decoder success!!!");  
        */
    }  
}  
package cn.kuwo.util;
  
import java.awt.image.BufferedImage;  
import jp.sourceforge.qrcode.data.QRCodeImage;  
  
public class TwoDimensionCodeImage implements QRCodeImage {  
  
    BufferedImage bufImg;  
      
    public TwoDimensionCodeImage(BufferedImage bufImg) {  
        this.bufImg = bufImg;  
    }  
      
    @Override  
    public int getHeight() {  
        return bufImg.getHeight();  
    }  
  
    @Override  
    public int getPixel(int x, int y) {  
        return bufImg.getRGB(x, y);  
    }  
  
    @Override  
    public int getWidth() {  
        return bufImg.getWidth();  
    }  
  
}

cn.kuwo.vo下的2个数据层

package cn.kuwo.vo;

import java.util.HashMap;

public class LoginUserVo {
    private static HashMap<String, UserVo> loginUserMap = new HashMap<String, UserVo>();
    private static LoginUserVo loginUserVo;
    public static LoginUserVo getVo(){
        if(loginUserVo == null){
            loginUserVo = new LoginUserVo();
        }
        return loginUserVo;
    }
    public static HashMap<String, UserVo> getLoginUserMap() {
        return loginUserMap;
    }
}
package cn.kuwo.vo;

public class UserVo {
    private String uname;
    private String upwd;
    public String getUname() {
        return uname;
    }
    public void setUname(String uname) {
        this.uname = uname;
    }
    public String getUpwd() {
        return upwd;
    }
    public void setUpwd(String upwd) {
        this.upwd = upwd;
    }
}

2个网页

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="js/jquery-1.11.0.min.js"></script>
<body>
    <div id="divCon">
        <img src="" id="QrCodeImg" />
    </div>
</body>
<script type="text/javascript">
    $(document).ready(function() {
        var uuid;
        $.get("/QrCodeLoginPro/GetQrCodeServlet", function(data, status) {
            var obj = eval("(" + data + ")");
            //存储UUID
            uuid = obj.uuid;
            //显示二维码
            $("#QrCodeImg").attr("src", obj.qrCodeImg);
            //开始验证登录
            validateLogin();
        });

        function validateLogin(){
            $.get("/QrCodeLoginPro/LongConnectionCheckServlet?uuid=" + uuid , function(data, status) {
                if(data == ""){
                    validateLogin();
                }else{
                    var obj = eval("(" + data + ")");
                    alert("登录成功了:" + obj.uname);
                }
            });
        }
    });
</script>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<style>
.l_m_l {
    float: left;
    font-size: 14px;
    padding: 5px 0 0 0;
     330px;
    color: #414141;
}

.l_m_linput {
    height: 31px;
    position: relative;
     300px;
    margin-bottom: 21px;
}

.l_m_linput span {
    float: left;
     78px;
    text-align: right;
    line-height: 31px;
}

input {
    float: left;
     195px;
    height: 24px;
    line-height: 24px;
    background: #f2f2f2;
    border: 1px solid #c4c4c4;
    padding: 2px 22px 2px 2px;
}

.l_mimacon {
    position: absolute;
    top: 6px;
    right: 6px;
     15px;
    height: 17px;
    background: url(img/l_mimacon.png)
        no-repeat;
}

.l_peoplecon {
    position: absolute;
    top: 7px;
    right: 6px;
     15px;
    height: 15px;
    background: url(img/l_peoplecon.png)
        no-repeat;
}

.l_m_lload a {
    display: block;
     154px;
    height: 40px;
    background:
        url(img/l_loadingbtn.png)
        no-repeat;
    margin: 0 auto;
    line-height: 40px;
    text-align: center;
    font-size: 18px;
    color: #52340c;
    text-decoration: none;
}
</style>
<script type="text/javascript" src="js/jquery-1.11.0.min.js"></script>
<body style="background-color: #333333">
    <div style="margin-left: 100px;"><img src="img/logo.png" /></div>
    <div class="l_m_l">
        <p class="l_m_linput">
            <span><font color="#fff">用户名：</font></span><input type="text" id="login_name" value="zijuntang"><em
                class="l_peoplecon"></em>
        </p>
        <p class="l_m_linput">
            <span><font color="#fff">密码：</font></span><input type="password" id="login_psw" value="xxxxxxxxx"><em
                class="l_mimacon"></em>
        </p>
        <div class="l_m_linput2"></div>
        <div class="l_m_lload">
            <a href="javascript:login();">登录</a>
        </div>
    </div>
</body>
<script type="text/javascript">
    //登录
    function login(){
        $.post("/QrCodeLoginPro/PhoneLoginServlet", {
            uuid : $.getUrlParam('uuid'),
            uname:$("#login_name").val(),
            upwd:$("#login_psw").val()
        }, function(data, status) {
            if(data == ""){
                alert("登录失败");
            }else{
                alert("登录成功");
            }
        });
    }
    
    //获取网页参数
    (function($){
        $.getUrlParam = function(name){
            var reg = new RegExp("(^|&)"+ name +"=([^&]*)(&|$)");
            var r = window.location.search.substr(1).match(reg);
            if (r!=null) return unescape(r[2]); return null;
        }
        })(jQuery);
</script>
</html>

web.xml配置文件

<?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_2_5.xsd"
    id="WebApp_ID" version="2.5">
    <display-name>QrCodeLoginPro</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>
    <servlet>
        <description></description>
        <display-name>长连接检查登录状态</display-name>
        <servlet-name>LongConnectionCheckServlet</servlet-name>
        <servlet-class>cn.kuwo.LongConnectionCheckServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LongConnectionCheckServlet</servlet-name>
        <url-pattern>/LongConnectionCheckServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <description>获取二维码图片以及uuid</description>
        <display-name>GetQrCodeServlet</display-name>
        <servlet-name>GetQrCodeServlet</servlet-name>
        <servlet-class>cn.kuwo.GetQrCodeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GetQrCodeServlet</servlet-name>
        <url-pattern>/GetQrCodeServlet</url-pattern>
    </servlet-mapping>

    <servlet>
        <description>手机扫描二维码之后进行登录</description>
        <display-name>PhoneLoginServlet</display-name>
        <servlet-name>PhoneLoginServlet</servlet-name>
        <servlet-class>cn.kuwo.PhoneLoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>PhoneLoginServlet</servlet-name>
        <url-pattern>/PhoneLoginServlet</url-pattern>
    </servlet-mapping>
</web-app>

此外还需要1个二维码开源包：QRCode.jar

源码下载：https://files.cnblogs.com/zijun/%E4%BA%8C%E7%BB%B4%E7%A0%81%E7%99%BB%E5%BD%95%E4%BE%8B%E5%AD%90.rar

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原文地址：https://www.cnblogs.com/zijun/p/3580125.html