Android二维码登录原理及生成与解析

二维码原理

三、二维码生成和解码工具

1.效果如下图所示。

2.二维码生成和解析的核心类

import java.awt.BasicStroke;import java.awt.Color;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Image;import java.awt.Shape;import java.awt.geom.RoundRectangle2D;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 { //二维码 SIZE private static final int CODE_IMG_SIZE = 235; // LOGO SIZE (为了插入图片的完整性，我们选择在最中间插入，而且长宽建议为整个二维码的1/7至1/4) private static final int INSERT_IMG_SIZE = CODE_IMG_SIZE/5; /** * 生成二维码(QRCode)图片 * @param content 存储内容 * @param imgPath 二维码图片存储路径 * @param imgType 图片类型 * @param insertImgPath logo图片路径 */ public void encoderQRCode(String content, String imgPath, String imgType, String insertImgPath) { try { BufferedImage bufImg = this.qRCodeCommon(content, imgType, insertImgPath); 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 */public void encoderQRCode(String content, OutputStream output, String imgType) { try { BufferedImage bufImg = this.qRCodeCommon(content, imgType, null); // 生成二维码QRCode图片 ImageIO.write(bufImg, imgType, output); } catch (Exception e) { e.printStackTrace; } } /** * @param content * @param imgType * @param size * @param imgPath 嵌入图片的名称 * @return */ private BufferedImage qRCodeCommon(String content, String imgType, String imgPath){ 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(15); // 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 = CODE_IMG_SIZE; 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 final int pixoff = 2; final int sz = 3; // 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 * sz + pixoff, i * sz + pixoff, sz, sz); } } } } else { throw new Exception("QRCode content bytes length = " + contentBytes.length + " not in [0, 800]."); } //嵌入logo if(imgPath != null) this.insertImage(bufImg, imgPath, true); gs.dispose; bufImg.flush; } catch (Exception e) { e.printStackTrace; } return bufImg; } private void insertImage(BufferedImage source, String imgPath, boolean needCompress) throws Exception { File file = new File(imgPath); if (!file.exists) { System.err.println(""+imgPath+" 该文件不存在！");return; } Image src = ImageIO.read(new File(imgPath)); int width = src.getWidth(null); int height = src.getHeight(null); if (needCompress) { // 压缩LOGO if (width > INSERT_IMG_SIZE) { width = INSERT_IMG_SIZE; } if (height > INSERT_IMG_SIZE) { height = INSERT_IMG_SIZE; } Image image = src.getScaledInstance(width, height, Image.SCALE_SMOOTH); BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = tag.getGraphics; g.drawImage(image, 0, 0, null); // 绘制缩小后的图 g.dispose; src = image; } // 插入LOGO Graphics2D graph = source.createGraphics; int x = (CODE_IMG_SIZE - width) / 2; int y = (CODE_IMG_SIZE - height) / 2; graph.drawImage(src, x, y, width, height, null); Shape shape = new RoundRectangle2D.Float(x, y, width, width, 6, 6); graph.setStroke(new BasicStroke(3f)); graph.draw(shape); graph.dispose; } /** * 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; } }

3.具体注意的地方

//二维码 SIZEprivate static final int CODE_IMG_SIZE = 235;// LOGO SIZE (为了插入图片的完整性，我们选择在最中间插入，而且长宽建议为整个二维码的1/7至1/4)private static final int INSERT_IMG_SIZE = CODE_IMG_SIZE/5;

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(15);

// 设置偏移量，不设置可能导致解析出错 final int pixoff = 2;final int sz = 3;// 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 * sz + pixoff, i * sz + pixoff, sz, sz); } } } }

四、二维码登录原理

1.原理图

2.GetQrCodeController.java

/** * @author hjzgg * 获取二维码图片 */@Controllerpublic class GetQrCodeController { @RequestMapping(value="/getTwoDemensionCode")@ResponseBody public String getTwoDemensionCode(HttpServletRequest request){ String uuid = UUID.randomUUID.toString.substring(0, 8);String ip = "localhost"; try { ip = InetAddress.getLocalHost.getHostAddress; } catch (UnknownHostException e) { e.printStackTrace; } //二维码内容 String content = "http://" + ip + ":8080/yycc-portal/loginPage?uuid=" + uuid; //生成二维码 String imgName = uuid + "_" + (int) (new Date.getTime / 1000) + ".png";String imgPath = request.getServletContext.getRealPath("/") + imgName; //String insertImgPath = request.getServletContext.getRealPath("/")+"img/hjz.jpg"; TwoDimensionCode handler = new TwoDimensionCode; handler.encoderQRCode(content, imgPath, "png", null); //生成的图片访问地址 String qrCodeImg = "http://" + ip + ":8080/yycc-portal/" + imgName; JSONObject json = new JSONObject; json.put("uuid", uuid); json.put("qrCodeImg", qrCodeImg); return json.toString; }}

3.LongConnectionCheckController.java

@Controllerpublic class LongConnectionCheckController { private static final int LONG_TIME_WAIT = 30000;//30s @Autowired private RedisTemplate<String, Object> redisTemplate;@RequestMapping(value="/longUserCheck") public String longUserCheck(String uuid){ long inTime = new Date.getTime; Boolean bool = true; while (bool) { try { Thread.sleep(500); } catch (InterruptedException e) { e.printStackTrace; } //检测登录 UserVo userVo = (UserVo) redisTemplate.opsForValue.get(uuid); System.out.println("LongConnectionCheckAction:" + userVo); if(userVo != null){ redisTemplate.delete(uuid); return "forward:/loginTest?username=" + userVo.getUsername + "&password=" + userVo.getPassword; }else{ if(new Date.getTime - inTime > LONG_TIME_WAIT){ bool = false; redisTemplate.delete(uuid); } } } return"forward:/longConnectionFail"; }@RequestMapping(value="/longConnectionFail") @ResponseBody public String longConnectionFail{ JSONObject json = new JSONObject; json.put("success", false); json.put("message", "长连接已断开!");return json.toString; }}

4.PhoneLoginController.java

/** * @author hjzgg * 手机登录验证 */@Controllerpublic classPhoneLoginController { @Autowired private RedisTemplate<String, Object> redisTemplate; @RequestMapping(value="/phoneLogin") public void phoneLogin(String uuid, String username, String password){ UserVo user = (UserVo) redisTemplate.opsForValue.get(uuid); if(user == null) { user = new UserVo(username, password); } System.out.println(user); redisTemplate.opsForValue.set(uuid, user); }@RequestMapping(value="/loginPage") public String loginPage(HttpServletRequest request, String uuid){ request.setAttribute("uuid", uuid); return "phone_login"; }}

五、源码下载