Java生成二维码（使用Google开源项目ZXing ）

1. 添加依赖

		<!--spring-web相关依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--Java二维码相关依赖-->
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>core</artifactId>
            <version>3.4.1</version>
        </dependency>
        <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.4.1</version>
        </dependency>

        <!--lombok相关依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

2. 创建工具类

package com.chen.qrcode.util;

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;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;

/**
 * 二维码生成工具类
 *
 * @author 撸码社区
 * @version 1.0
 * @date 2022-04-26 21:40
 */
public class QrCodeUtil {

    /**
     * 生成二维码,返回字节流
     *
     * @param text   二维码需要包含的信息
     * @param width  二维码宽度
     * @param height 二维码高度
     */
    public static byte[] generateQrCodeByte(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);
        return pngOutputStream.toByteArray();
    }

    /**
     * 生成二维码,保存到本地
     *
     * @param text     二维码需要包含的信息
     * @param width    二维码宽度
     * @param height   二维码高度
     * @param filePath 图片保存路径
     */
    public 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);
    }

}

3. 创建测试控制层

package com.chen.qrcode.controller;

import com.chen.qrcode.util.QrCodeUtil;
import com.google.zxing.WriterException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Objects;

/**
 * @author 撸码社区
 * @version 1.0
 * @date 2022/4/26 21:50
 */
@RestController
@RequestMapping("/qr-code")
@Slf4j
public class QrCodeController {

    /**
     * url如果为文本,扫码则是文本信息
     * url如果为链接,则进行对应的跳转,可在url后携带参数进行传递
     * 如: https://www.baidu.com?test=12345
     */
    public static String url = "https://www.baidu.com/";

    /**
     * 方法一：响应文件流
     *
     * @return ResponseEntity响应文件流
     */
    @GetMapping("methodOne")
    public ResponseEntity<byte[]> methodOne() {
        byte[] qrCode = null;
        try {
            qrCode = QrCodeUtil.generateQrCodeByte(url, 350, 350);
        } catch (Exception e) {
            log.info("Exception:{}", e.getMessage());
        }
        // Header设置文件类型（对于ResponseEntity响应的方式，必须设置文件类型）
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.IMAGE_PNG);

        return new ResponseEntity<>(qrCode, headers, HttpStatus.CREATED);
    }

    /**
     * 方法二：响应文件流
     *
     * @param response response原生响应文件流
     */
    @GetMapping("methodTwo")
    public void methodTwo(HttpServletResponse response) throws IOException {
        byte[] qrCode = null;
        try {
            qrCode = QrCodeUtil.generateQrCodeByte(url, 350, 350);
        } catch (Exception e) {
            log.info("Exception:{}", e.getMessage());
        }
        // Header设置文件类型（ContentType不设置也没事）
        response.setContentType(MediaType.IMAGE_PNG_VALUE);
        response.getOutputStream().write(Objects.requireNonNull(qrCode));
    }

    /**
     * 方法三：下载到本地
     *
     */
    @GetMapping("methodThree")
    public void methodThree() throws IOException, WriterException {
        //下载路径及文件名
        String filePath = "D:\or-code.png";
        QrCodeUtil.generateQrCodeImage(url, 350, 350, filePath);
    }

}

4. 测试方法

• methodOne
  

• methodTwo
  

• methodThree