java生成二维码扫码网页自动登录功能

找了很多资料，七七八八都试了一遍，最终写出来了这个功能。

菜鸟一枚，此文只为做笔记。

简单的一个生成二维码，通过网页确认登录，实现二维码页面跳转到主页面。

有三个servlet：

CodeServlet.java 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/xxxx/login.jsp?uuid= xxxx

LongConnectionCheckServlet.java

　　进行长连接轮询操作，参数为uuid，查找loginMap中是否有此uuid，如果有则停止轮询，loginMap中remove这个uuid

PhoneLoginServlet.java 干2件事

　　a:检测登录，查看是否有此uuid

　　b:登录成功后将登录信息插入到loginMap中去，uuid为key

-------- Servlet 需要配置web.xml --------

UserLoginInfoVO.java

　　 用户登录信息存储用户名密码（其他的还可以加，我只写了简单的）

LoginUser.java

　　用HashMap存用户登录信息

TwoDimensionCode.java

　　最关键的生成二维码的类，实现QRCodeImage，需要QRCode.jar包

　　QRCode.jar下载地址：http://vdisk.weibo.com/s/A25JOYrYFK9xO

UserLoginInfoVO.java

public class UserLoginInfoVO {
    private String userName;
    private String userPass;

    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPass() {
        return userPass;
    }
    public void setUserPass(String userPass) {
        this.userPass = userPass;
    }
}

LoginUser.java

import java.util.HashMap;

public class LoginUser {
    private static HashMap<String, UserLoginInfoVO> loginMap = new HashMap<String, UserLoginInfoVO>();
    private static UserLoginInfoVO userLoginInfoVO;

    public static UserLoginInfoVO getVO() {
        if (userLoginInfoVO == null) {
            userLoginInfoVO = new UserLoginInfoVO();
        }
        return userLoginInfoVO;
    }
    public static HashMap<String, UserLoginInfoVO> getLoginMap() {
        return loginMap;
    }

}

TwoDimensionCode.java

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 com.swetake.util.Qrcode;
import jp.sourceforge.qrcode.QRCodeDecoder;
import jp.sourceforge.qrcode.exception.DecodingFailedException;

public class TwoDimensionCode {
    /**
     * 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 output
     *            输出流
     * @param size
     *            二维码尺寸
     */
    public void encoderQRCode(String content, String imgPath) {
        this.encoderQRCode(content, imgPath, "png", 7);
    }

    public void encoderQRCode(String content, OutputStream output) {
        this.encoderQRCode(content, output, "png", 7);
    }

    public void encoderQRCode(String content, String imgPath, String imgType) {
        this.encoderQRCode(content, imgPath, imgType, 7);
    }

    public void encoderQRCode(String content, OutputStream output, String imgType) {
        this.encoderQRCode(content, output, imgType, 7);
    }

    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();
        }
    }

    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
     *
     * @return BufferedImage
     */
    private BufferedImage qRCodeCommon(String content, String imgType, int size) {
        BufferedImage bufImg = null;
        try {
            Qrcode qrcode = 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
            qrcode.setQrcodeErrorCorrect('M');
            qrcode.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
            qrcode.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);
            // BufferedImage.TYPE_INT_RGB表示一个图像，该图像具有整数像素的 8 位 RGB 颜色
            bufImg = new BufferedImage(imgSize, imgSize, BufferedImage.TYPE_INT_RGB);

            Graphics2D gs = bufImg.createGraphics();
            // 设置背景颜色
            gs.setBackground(Color.WHITE);
            // 画矩形
            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) {
                // calQrcode()让字符串生成二维码。
                boolean[][] codeOut = qrcode.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;
    }
}

CodeServlet.java

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 com.dsjstudio.loanfront.useras.utils.TwoDimensionCode;

public class CodeServlet 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://localhost:8080/xxxx/index.jsp?uuid=" + uuid;
        // 生成二维码
        String imgName = "image_" + uuid + ".png";
        String imgPath = "D:/images/" + imgName;

        TwoDimensionCode handler = new TwoDimensionCode();
        handler.encoderQRCode(content, imgPath, "png");

        System.out.println(content);
        // 生成的图片访问地址
        String qrCodeImg = "http://localhost:8080/images/" + imgName;
        String jsonStr = "{\"uuid\":" + uuid + ",\"qrCodeImg\":\"" + qrCodeImg + "\"}";
        out.print(jsonStr);
        out.flush();
        out.close();

    }
}

LongConnectionCheckServlet.java

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 com.dsjstudio.loanfront.useras.controller.user.controller.LoginUser;
import com.dsjstudio.loanfront.useras.controller.user.vo.UserLoginInfoVO;

public class LongConnectionCheckServlet 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 {

        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(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            // 检测登录
            UserLoginInfoVO userVo = LoginUser.getLoginMap().get(uuid);
            System.out.println("userVo:" + userVo);
            if (userVo != null) {
                bool = false;
                jsonStr = "{\"uname\":\"" + userVo.getUserName() + "\"}";
                LoginUser.getLoginMap().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();
    }

}

PhoneLoginServlet.java

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 com.dsjstudio.loanfront.useras.controller.user.controller.LoginUser;
import com.dsjstudio.loanfront.useras.controller.user.vo.UserLoginInfoVO;

public class PhoneLoginServlet 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 {
        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
            UserLoginInfoVO userVo = LoginUser.getLoginMap().get(uuid);
            if (userVo == null) {
                userVo = new UserLoginInfoVO();
                userVo.setUserName(uname);
                userVo.setUserPass(upwd);
                LoginUser.getLoginMap().put(uuid, userVo);
            }
        }
        PrintWriter out = response.getWriter();
        out.print(bool);
        out.flush();
        out.close();
    }

}

两个jsp页面：

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script type="text/javascript">
    $(document).ready(function() {
        var uuid;
        //alert("1");
        $.get("/dsjstudio-loan-user-as/CodeServlet", function(data, status) {
            var obj = eval("(" + data + ")");
            //alert("2");
            //存储UUID
            uuid = obj.uuid;
            //显示二维码
            $("#QrCodeImg").attr("src", obj.qrCodeImg);
           // alert(obj.qrCodeImg);
            //开始验证登录
            validateLogin();
        });
        function validateLogin(){
            $.get("/dsjstudio-loan-user-as/LongConnectionCheckServlet?uuid=" + uuid , function(data, status) {
                if(data == ""){
                    validateLogin();
                }else{
                    var obj = eval("(" + data + ")");
                    alert("欢迎您回家:" + obj.uname);
                    window.location.href='http://www.baidu.com';
                }
            });
        }
    });
</script>
</head>
<body>
<h1>哥么敢不敢扫一下！</h1>
    <div id="divCon">
        <img src="" id="QrCodeImg" />
    </div>
</body>
</html>

login.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>点确认吧小伙子</title>
<script type="text/javascript" src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script type="text/javascript">
    //登录
    function login()
        $.post("/dsjstudio-loan-user-as/PhoneLoginServlet", {
            uuid : $.getUrlParam('uuid'),
            uname:$("#login_name").val(),
            upwd:$("#login_psw").val()
        }, function(data, status) {
            if(data == ""){
                alert("登录失败");
            }else{
                alert("登录成功");
            }
        });
    }
    //获取网页参数
    (function($){
            $.getUrlParam = function(name){
                //这个正则是寻找&+url参数名字=值+&
                var reg = new RegExp("(^|&)"+ name +"=([^&]*)(&|$)");
                //这里是开始匹配，找到了返回对应url值，没找到返回null。
                var r = window.location.search.substr(1).match(reg);
                if (r!=null) return unescape(r[2]); return null;
            }
        })(jQuery);
</script>
</head>
<body>
    <div>
        <p>
            <span>名称：</span>
            <input type="text" id="login_name" value="lingzi">
        </p>
        <p>
            <span>密码：</span>
            <input type="password" id="login_psw" value="xxxxxxxxx">
        </p>
        <div>
            <a href="javascript:login()">登录</a>
        </div>
    </div>
</body>
</html>

因为连的是本地的tomcat，所以是直接电脑上操作，二维码出来，有一个uuid打印在Console上，复制粘贴到网址上

实现效果图：

Console上uuid打印出来62951

 点击登录

返回index.jsp页面查看，成功~点击确认跳转页面啦~

web.xml配置

　　<servlet>
        <description></description>
        <display-name>长连接检查登录状态</display-name>
        <servlet-name>LongConnectionCheckServlet</servlet-name>
        <servlet-class>com.dsjstudio.loanfront.useras.controller.user.servlet.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>CodeServlet</display-name>
        <servlet-name>CodeServlet</servlet-name>
        <servlet-class>com.dsjstudio.loanfront.useras.controller.user.servlet.CodeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>CodeServlet</servlet-name>
        <url-pattern>/CodeServlet</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>com.dsjstudio.loanfront.useras.controller.user.servlet.PhoneLoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>PhoneLoginServlet</servlet-name>
        <url-pattern>/PhoneLoginServlet</url-pattern>
    </servlet-mapping>