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IDint 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mapUserVo 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UUIDuuid = 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;width: 330px;color: #414141;}.l_m_linput {height: 31px;position: relative;width: 300px;margin-bottom: 21px;}.l_m_linput span {float: left;width: 78px;text-align: right;line-height: 31px;}input {float: left;width: 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;width: 15px;height: 17px;background: url(img/l_mimacon.png)no-repeat;}.l_peoplecon {position: absolute;top: 7px;right: 6px;width: 15px;height: 15px;background: url(img/l_peoplecon.png)no-repeat;}.l_m_lload a {display: block;width: 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"><emclass="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"><emclass="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="/2001/XMLSchema-instance"xmlns="/xml/ns/javaee"xsi:schemaLocation="/xml/ns/javaee /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：/zijun/%E4%BA%8C%E7%BB%B4%E7%A0%81%E7%99%BB%E5%BD%95%E4%BE%8B%E5%AD%90.rar
