java后台生成二维码

需求：生成的二维码可以在微信、支付宝、等手机扫码设备可识别内容!

1.导入maven

<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>

2.1：先举例生成二维码保存本地：

/**
 * 存放本地固定路径
 */
private static final String QR_CODE_IMAGE_PATH = "F:\\kedaSoft\\appinterface\\WebRoot\\ycs.png";

private static void generateQRCodeImage(String text, Integer width, Integer 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("测试，保存在本地的二维码", 350, 350, QR_CODE_IMAGE_PATH);
        } catch (WriterException e) {
            System.out.println("写入异常 :: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("io异常 IOException :: " + e.getMessage());
        }

    }

如图所示：找到保存的路径查看：

2.2：举例生成二维码不保存本地使用web浏览器访问：

    /**
     *
     * @param text 扫码显示内容
     * @param width 二维码长度
     * @param height 二维码高度
     * @return 返回byte数组
     * @throws WriterException 写入异常
     * @throws IOException io异常
     */
    public static byte[] getQRCodeImage(String text, Integer width, Integer height) throws WriterException, IOException{
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            // 解决中文乱码
            HashMap<EncodeHintType, Object> hints = new HashMap<>(16);
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            BitMatrix encode = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height,hints);
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            MatrixToImageWriter.writeToStream(encode,"PNG",byteArrayOutputStream);
            return byteArrayOutputStream.toByteArray();
    }

    // 这里我是用的jfinal框架，如你用的是spring：加上RequestMaping（“/qrCode”）即可。

public void qrCode(){
        HttpServletResponse response = this.getResponse();
        //二维码内的信息
        String info = "二维码内的信息";
        try {
            byte[]     qrCode = QrCodeGenerator.getQRCodeImage(info, 360, 360);
            OutputStream outputStream = response.getOutputStream();
            outputStream.write(qrCode);
            response.setCharacterEncoding("utf-8");
            response.setContentType("image/png");
            outputStream.flush();
          } catch (WriterException e) {
        System.out.println("写入异常 :: " + e.getMessage());
        } catch (IOException e) {
        System.out.println("io异常 IOException :: " + e.getMessage());
        }
    }

 

 3.：全部放到一个工具类：

package com.wom.utils;

/**
 * @author ycs
 * @date 2022/2/14
 */
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.util.HashMap;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
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 {
    /**
     * 存放本地固定路径
     */
    private static final String QR_CODE_IMAGE_PATH = "F:\\kedaSoft\\appinterface\\WebRoot\\ycs.png";

    private static void generateQRCodeImage(String text, Integer width, Integer 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);

    }

    /**
     *
     * @param text 扫码显示内容
     * @param width 二维码长度
     * @param height 二维码高度
     * @return 返回byte数组
     * @throws WriterException 写入异常
     * @throws IOException io异常
     */
    public static byte[] getQRCodeImage(String text, Integer width, Integer height) throws WriterException, IOException{
            QRCodeWriter qrCodeWriter = new QRCodeWriter();
            // 解决中文乱码
            HashMap<EncodeHintType, Object> hints = new HashMap<>(16);
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            BitMatrix encode = qrCodeWriter.encode(text, BarcodeFormat.QR_CODE, width, height,hints);
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            MatrixToImageWriter.writeToStream(encode,"PNG",byteArrayOutputStream);
            return byteArrayOutputStream.toByteArray();
    }

    public static void main(String[] args) {
        try {
            generateQRCodeImage("测试，保存在本地的二维码", 350, 350, QR_CODE_IMAGE_PATH);
        } catch (WriterException e) {
            System.out.println("写入异常 :: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("io异常 IOException :: " + e.getMessage());
        }

    }


}