二维码

1.直接生成图片（直接生成图片不需要web程序，maven工程即可） 2.将二维码转为字节数组，然后在web页面显示。。

1.添加Zxing的依赖

<dependency>

            <groupId>com.google.zxing</groupId>

            <artifactId>core</artifactId>

            <version>3.3.0</version>

        </dependency>

        <dependency>

            <groupId>com.google.zxing</groupId>

            <artifactId>javase</artifactId>

            <version>3.3.0</version>

        </dependency>

2.保存信息为二维码图片

名为generateQRCodeImage方法，将字符串封装成二维码、设置二维码的宽度和高度、声明二维码保存的路径与图片名称。

package org.thinkingingis.utils;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.nio.file.FileSystems;

import java.nio.file.Path;

import com.google.zxing.BarcodeFormat;

import com.google.zxing.WriterException;

import com.google.zxing.client.j2se.MatrixToImageWriter;

import com.google.zxing.common.BitMatrix;

import com.google.zxing.qrcode.QRCodeWriter;

public class QRCodeGenerator {

    private static final String QR_CODE_IMAGE_PATH = “/Users/gisboy/Desktop/MyQRCode.png”;

    private static void generateQRCodeImage(String text, int width, int height, String filePath) throws WriterException, IOException {

        QRCodeWriter qrCodeWriter = new QRCodeWriter();

        BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height);

        Path path = FileSystems.getDefault().getPath(filePath);

        MatrixToImageWriter.writeToPath(bitMatrix, “PNG”, path);

    }

    public static void main(String[] args) {

        try {

            generateQRCodeImage(“This is my first QR Code”, 350, 350, QR_CODE_IMAGE_PATH);

        } catch (WriterException e) {

            System.out.println(“Could not generate QR Code, WriterException :: ” + e.getMessage());

        } catch (IOException e) {

            System.out.println(“Could not generate QR Code, IOException :: ” + e.getMessage());

        }

    }

}

上面的代码将会生成一个内容为“This is my first QR Code”二维码，并保存在桌面，如下图：

上面的方法是将二维码保存为图片，如果你不想将二维码保存为图片，也可以将其保存为字节数组，可以用zxing 库提供的MatrixToImageWriter.writeToStream()方法：

public static byte[] getQRCodeImage(String text, int width, int height) throws WriterException, IOException {

        QRCodeWriter qrCodeWriter = new QRCodeWriter();

        BitMatrix bitMatrix = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height);

        ByteArrayOutputStream pngOutputStream = new ByteArrayOutputStream();

        MatrixToImageWriter.writeToStream(bitMatrix, “PNG”, pngOutputStream);

        byte[] pngData = pngOutputStream.toByteArray();

        return pngData;

    }