java利用zxing生成二维码

首先需要相应jar包

maven依赖添加

<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>

直接写在controller里面的二维码生成

private static final int WIDTH = 60;
	   
    private static final int HEIGHT = 60;

	private static final String CHARSET = "UTF-8";
    
	private static final String FORMAT_NAME = "JPG";
	@GetMapping(value = "/showQRCode/{id}")
	public void showQRCode(@PathVariable("id") String id,HttpServletResponse resp) throws Exception {
		GadleeSignAddress gadleeSignAddress = districtService.selectRegionById(id);
		String content = gadleeSignAddress.toString();
		Map<EncodeHintType,Object> config = new HashMap<>();
		config.put(EncodeHintType.CHARACTER_SET,CHARSET);//字符编码
		config.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);//纠错等级
		config.put(EncodeHintType.MARGIN, 0);
		BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE,WIDTH,HEIGHT,config);
		Path file = new File("g:/QRCode"+File.separator+IdGen.uuid()+".png").toPath();
		MatrixToImageWriter.writeToPath(bitMatrix,FORMAT_NAME,file);
		System.out.println("二维码生成完毕，已经保存至相关路径中。");
//		下面是将其path保存到数据库,并以流的形式返回给前端，这里需要HttpServletResponse的相应输出流
		File filePath=new File(file.toString());
		String path=filePath.getAbsolutePath();
		GadleeSignAddress gsa = new GadleeSignAddress();
		gsa.setId(id);
		gsa.setName(gadleeSignAddress.getName());
		gsa.setCustomer(gadleeSignAddress.getCustomer());
		gsa.setPath(path);
		districtService.savePath(gsa);
		OutputStream os = resp.getOutputStream();//取得输出流
		MatrixToImageWriter.writeToStream(bitMatrix, FORMAT_NAME, os);//写入文件刷新
		}

        然后优化提出来一个二维码生成的工具类，和controller，这里考虑了既要将二维码显示在前端，也要将二维码保存下来，并将路径保存到相应数据库中

工具类如下：

package com.topband.cloud.common.utils;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;

import javax.imageio.ImageIO;

import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

public class QRCodeUtil {
	
	private static final int WIDTH = 60;
   
    private static final int HEIGHT = 60;

	private static final String CHARSET = "UTF-8";
    
	public static final String FORMAT_NAME = "JPG";
	
	
	public static Map<String,Object> createQRCode(String content) throws Exception {
	Map<EncodeHintType,Object> config = new HashMap<>();
	config.put(EncodeHintType.CHARACTER_SET,CHARSET);//字符编码
	config.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);//纠错等级
	config.put(EncodeHintType.MARGIN, 0);
	BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE,WIDTH,HEIGHT,config);
	Path file = new File("g:/QRCode"+File.separator+IdGen.uuid()+".png").toPath();
	MatrixToImageWriter.writeToPath(bitMatrix,FORMAT_NAME,file);
	System.out.println("二维码生成完毕，已经保存至相关路径中。");
	File filePath=new File(file.toString());
	String path=filePath.getAbsolutePath();
	Map<String,Object> data = new HashMap<String,Object>();
	data.put("qrcode", bitMatrix);
	data.put("path", path);
	return data;
}
}

如上代码为了在controller中保存路径到数据库，同时为了将二维码刷新到前端，故而将路径和二维码生成的图像通过map返回来，在controller中取出并作适当类型转换，然后就可以实现。

controller代码如下：

@GetMapping(value = "/showQRCode/{id}")
	public void showQRCode(@PathVariable("id") String id,HttpServletResponse resp) throws Exception {
		GadleeSignAddress gadleeSignAddress = districtService.selectRegionById(id);
		String content = gadleeSignAddress.toString();
		Map<String,Object> data = QRCodeUtil.createQRCode(content);
		String path = (String) data.get("path");
		BitMatrix bitMatrix = (BitMatrix) data.get("qrcode");
		GadleeSignAddress gsa = new GadleeSignAddress();
		gsa.setId(id);
		gsa.setName(gadleeSignAddress.getName());
		gsa.setCustomer(gadleeSignAddress.getCustomer());
		gsa.setPath(path);
		districtService.savePath(gsa);
		OutputStream os = resp.getOutputStream();//取得输出流
		MatrixToImageWriter.writeToStream(bitMatrix, QRCodeUtil.FORMAT_NAME, os);//写入文件刷新
		}

测试均ok，如下

解析二维码的代码也放上

//	解析二维码
    public static void readQRCode(File file){
    	
    	try {
    		MultiFormatReader formatReader = new MultiFormatReader();
			BufferedImage image = ImageIO.read(file);
			BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(image)));
			HashMap hints = new HashMap();
			hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
			Result result = formatReader.decode(binaryBitmap, hints);
			} catch (NotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }