二维码分为好多种，我们最常用的是qrcode类型的二维码，以下有三种生成方式以及解析方式：
附所需jar包或者js地址
第一种：依赖qrcode.jar
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.UnsupportedEncodingException;
import javax.imageio.ImageIO;
import com.swetake.util.Qrcode;
/**获取qrcode jar包 https://osdn.jp/projects/qrcode
* 生成qrcode二维码
* @author fangyi
*
*/
public class CreateQrCode {
public static void main(String[] args) throws Exception {
Qrcode qrcode= new Qrcode();
qrcode.setQrcodeErrorCorrect('M');//纠错等级
qrcode.setQrcodeEncodeMode('B');//N代表数字 A代表字母 B代表其他
qrcode.setQrcodeVersion(7);//版本
String qrData ="www.baidu.com";//二维码信息内容
int width=67+12*(7-1);
int height=67+12*(7-1);
BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//画图工具
Graphics2D gs= bufferedImage.createGraphics();
//设置属性
gs.setBackground(Color.WHITE);
gs.setColor(Color.BLACK);
gs.clearRect(0, 0, width, height);
//填充
int pixoff=2;//偏移量
byte[] d = qrData.getBytes("gb2312");//编码防止有中文
if (0 < d.length && d.length<120) {
boolean[][] s = qrcode.calQrcode(d);
for (int i = 0; i < s.length; i++) {
for (int j = 0; j < s.length; j++) {
if(s[j][i]){
gs.fillRect(i*3+pixoff, j*3+pixoff, 3, 3);
}
}
}
}
//关闭资源，并保存文件
gs.dispose();
bufferedImage.flush();
ImageIO.write(bufferedImage, "png", new File("D:/qrcode.jpg"));//输出到指定地方
}
}import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import jp.sourceforge.qrcode.QRCodeDecoder;
/**
* 读取制定路径下的qrcode信息
* @author fangyi
*
*/
public class ReaderQrcode {
public static void main(String[] args) throws IOException {
//指定的二维码文件路径
File file= new File("D:/jqueryqrcode.png");
BufferedImage bufferedImage = ImageIO.read(file);
QRCodeDecoder qrCodeDecoder = new QRCodeDecoder();
String result = new String(qrCodeDecoder.decode(new MyQRCodeImage(bufferedImage)),"gb2312");
//输出结果
System.out.println(result);
bufferedImage.flush();
}
}
import java.awt.image.BufferedImage;
import jp.sourceforge.qrcode.data.QRCodeImage;
/**
* 自定义QRCodeImage类实现QRCodeImage 供读取时所用
* @author fangyi
*
*/
public class MyQRCodeImage implements QRCodeImage {
BufferedImage bufferedImage ;
public MyQRCodeImage(BufferedImage bufferedImage) {
super();
this.bufferedImage = bufferedImage;
}
@Override
public int getHeight() {
return bufferedImage.getHeight();
}
@Override
public int getPixel(int arg0, int arg1) {
return bufferedImage.getRGB(arg0, arg1);
}
@Override
public int getWidth() {
return bufferedImage.getWidth();
}
}
<%@ 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>生成二维码</title>
<!-- js地址https://github.com/jeromeetienne/jquery-qrcode -->
<script type="text/javascript" src="<%=request.getContextPath() %>/js/jquery.min.js"></script>
<script type="text/javascript" src="<%=request.getContextPath() %>/js/jquery.qrcode.min.js"></script>
</head>
<body>
生成二维码如下：<br><br><br>
<div id="qrcode"></div>
<script type="text/javascript">
$('#qrcode').qrcode("www.baidu.com"); //生产二维码
/* jquery('#qrcode').qrcode({width: 64,height: 64,text: "size doesn't matter"}); */
</script>
</body>
</html>
import java.io.File;
import java.io.IOException;
import java.util.Hashtable;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
/**
* zxing jar包地址 https://github.com/Candy1575/QRcode
* 依赖MatrixToImageWriter类
* @author fangyi
*
*/
public class EncodeTest {
public static void Encode_QR_CODE() throws IOException, WriterException{
String contents = "ZXing 二维码内容1234!"; // 二维码内容
int width = 430; // 二维码图片宽度 300
int height = 430; // 二维码图片高度300
String format = "gif";// 二维码的图片格式 gif
Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
// 指定纠错等级,纠错级别（L 7%、M 15%、Q 25%、H 30%）
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
// 内容所使用字符集编码
hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
// hints.put(EncodeHintType.MAX_SIZE, 350);//设置图片的最大值
// hints.put(EncodeHintType.MIN_SIZE, 100);//设置图片的最小值
hints.put(EncodeHintType.MARGIN, 1);//设置二维码边的空度，非负数
BitMatrix bitMatrix = new MultiFormatWriter().encode(contents,//要编码的内容
//编码类型，目前zxing支持：Aztec 2D,CODABAR 1D format,Code 39 1D,Code 93 1D ,Code 128 1D,
//Data Matrix 2D , EAN-8 1D,EAN-13 1D,ITF (Interleaved Two of Five) 1D,
//MaxiCode 2D barcode,PDF417,QR Code 2D,RSS 14,RSS EXPANDED,UPC-A 1D,UPC-E 1D,UPC/EAN extension,UPC_EAN_EXTENSION
BarcodeFormat.QR_CODE,
width, //条形码的宽度
height, //条形码的高度
hints);//生成条形码时的一些配置,此项可选
// 生成二维码
File outputFile = new File("D:" + File.separator + "mycode.gif");//指定输出路径
MatrixToImageWriter.writeToFile(bitMatrix, format, outputFile);
}
public static void main(String[] args) throws Exception {
try {
Encode_QR_CODE();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;
import com.google.zxing.common.BitMatrix;
/**
* 二维码的生成需要借助MatrixToImageWriter类，
* 该类是由Google提供的，可以将该类直接拷贝到源码中使用，当然你也可以自己写个
* 生产条形码的基类 依赖LogoConfig类
*/
public class MatrixToImageWriter {
private static final int BLACK = 0xFF000000;//用于设置图案的颜色
private static final int WHITE = 0xFFFFFFFF; //用于背景色
private MatrixToImageWriter() {
}
public static BufferedImage toBufferedImage(BitMatrix matrix) {
int width = matrix.getWidth();
int height = matrix.getHeight();
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
image.setRGB(x, y, (matrix.get(x, y) ? BLACK : WHITE));
// image.setRGB(x, y, (matrix.get(x, y) ? Color.YELLOW.getRGB() : Color.CYAN.getRGB()));
}
}
return image;
}
public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {
BufferedImage image = toBufferedImage(matrix);
//设置logo图标
LogoConfig logoConfig = new LogoConfig();
image = logoConfig.LogoMatrix(image);
if (!ImageIO.write(image, format, file)) {
throw new IOException("Could not write an image of format " + format + " to " + file);
}else{
System.out.println("图片生成成功！");
}
}
public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {
BufferedImage image = toBufferedImage(matrix);
//设置logo图标
LogoConfig logoConfig = new LogoConfig();
image = logoConfig.LogoMatrix(image);
if (!ImageIO.write(image, format, stream)) {
throw new IOException("Could not write an image of format " + format);
}
}
}
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
/**
* 二维码 添加自定义 logo图标 处理的方法,
* 模仿微信自动生成二维码效果，有圆角边框，logo和二维码间有空白区，logo带有灰色边框
* @author fangyi
*
*/
public class LogoConfig {
/**
* 设置 logo
* @param matrixImage 源二维码图片
* @return 返回带有logo的二维码图片
* @throws IOException
* @author Administrator sangwenhao
*/
public BufferedImage LogoMatrix(BufferedImage matrixImage) throws IOException{
/**
* 读取二维码图片，并构建绘图对象
*/
Graphics2D g2 = matrixImage.createGraphics();
int matrixWidth = matrixImage.getWidth();
int matrixHeigh = matrixImage.getHeight();
/**
* 读取Logo图片
*/
BufferedImage logo = ImageIO.read(new File("C:\\Users\\fangyi\\Pictures\\code-wallpaper-18.png"));
//开始绘制图片
g2.drawImage(logo,matrixWidth/5*2,matrixHeigh/5*2, matrixWidth/5, matrixHeigh/5, null);//绘制
BasicStroke stroke = new BasicStroke(5,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
g2.setStroke(stroke);// 设置笔画对象
//指定弧度的圆角矩形
RoundRectangle2D.Float round = new RoundRectangle2D.Float(matrixWidth/5*2, matrixHeigh/5*2, matrixWidth/5, matrixHeigh/5,20,20);
g2.setColor(Color.white);
g2.draw(round);// 绘制圆弧矩形
//设置logo 有一道灰色边框
BasicStroke stroke2 = new BasicStroke(1,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
g2.setStroke(stroke2);// 设置笔画对象
RoundRectangle2D.Float round2 = new RoundRectangle2D.Float(matrixWidth/5*2+2, matrixHeigh/5*2+2, matrixWidth/5-4, matrixHeigh/5-4,20,20);
g2.setColor(new Color(128,128,128));
g2.draw(round2);// 绘制圆弧矩形
g2.dispose();
matrixImage.flush() ;
return matrixImage ;
}
}
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import com.google.zxing.Binarizer;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.EncodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.BitArray;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
/**
* 读取zxing类型下的二维码信息
* @author fangyi
*
*/
public class ReadQrCode_Zxing {
@SuppressWarnings("unchecked")
public static void main(String[] args) {
try {
MultiFormatReader formatReader = new MultiFormatReader();
//读取指定的二维码文件
File file= new File("D:\\mycode.gif");
BufferedImage bufferedImage =ImageIO.read(file);
BinaryBitmap binaryBitmap= new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(bufferedImage)));
//定义二维码参数
Map hints= new HashMap<>();
hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
Result result = formatReader.decode(binaryBitmap, hints);
//输出相关的二维码信息
System.out.println("解析结果"+result.toString());
System.out.println("二维码格式类型"+result.getBarcodeFormat());
System.out.println("二维码文本内容"+result.getText());
bufferedImage.flush();
} catch (NotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
用二维码进行添加好友获取好友信息是用到VCard
微信扫码登陆网页原理：通过堵塞等待的长连接，近乎实时的获得信息。 对于验证过程，Open API 一般是通过授权令牌（Token）来解决的，原理是当用户通过授权后，分配一个限定条件下的令牌（如限制本机访问、限制授权有效时间、限制同时登录设备数等），使获得授权的用户仅在有限的前提下能访问相关服务。 像计算机休眠后曾做的授权就自动收回了，这样就有效的避免了在别人电脑上（尤其是网吧）打开，但忘记关闭或退出这类安全问题了。
实现可借鉴已有博客：https://www.cnblogs.com/zijun/p/3580125.html