java生成二维码

添加依赖

<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>

二维码工具类

package com.ds.system.utils.report;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

public class QRCodeUtils {

    public static BitMatrix createCode(String content) throws IOException {
        //二维码的宽高
        int width = 200;
        int height = 200;

        //其他参数，如字符集编码
        Map<EncodeHintType, Object> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        //容错级别为H
        hints.put(EncodeHintType.ERROR_CORRECTION , ErrorCorrectionLevel.H);
        //白边的宽度，可取0~4
        hints.put(EncodeHintType.MARGIN , 0);

        BitMatrix bitMatrix = null;
        try {
            bitMatrix = new MultiFormatWriter().encode(content,
                    BarcodeFormat.QR_CODE, width, height, hints);

        } catch (WriterException e) {
            e.printStackTrace();
        }

        return bitMatrix;
    }

    public static Boolean generateCode(BitMatrix matrix, String format, OutputStream stream){
        try {
            MatrixToImageWriter.writeToStream(matrix , format , stream);
            return true;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }
    }

}

web测试

    @GetMapping("/QR")
    public void QR(HttpServletResponse response) throws IOException {
        response.reset();
        response.setContentType("image/jpg");
        //不需要缓存
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        ServletOutputStream outputStream = response.getOutputStream();
        BitMatrix bitMatrix = QRCodeUtils.createCode("nihao");
        QRCodeUtils.generateCode(bitMatrix , "jpg" , outputStream);

    }
}