Java实现二维码扫码登录功能

具体要实现的功能：生成特定二维码，通过网页确认登录，实现二维码页面跳转到主页面

以下是具体类功能说明：

CodeServlet.java
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
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

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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>

<title>Insert title here</title>

$(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>

</body>

</html>

<%@ 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>

<title>点确认吧小伙子</title>

//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>

</p>

<p>

</p>

<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

<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>

<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>

<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>

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