Java生成二维码（使用Google开源项目ZXing ）

		
        
            org.springframework.boot
            spring-boot-starter-web
        

        
        
            com.google.zxing
            core
            3.4.1
        
        
            com.google.zxing
            javase
            3.4.1
        

        
        
            org.projectlombok
            lombok
        

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;


public class QrCodeUtil {

    
    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();
    }

    
    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);
    }

}

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;


@RestController
@RequestMapping("/qr-code")
@Slf4j
public class QrCodeController {

    
    public static String url = "https://www.baidu.com/";

    
    @GetMapping("methodOne")
    public ResponseEntity 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);
    }

    
    @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));
    }

    
    @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);
    }

}

• methodOne
  

• methodTwo
  

• methodThree