二维码---生成并下载二维码

package com.epalmpay.util;

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 org.apache.commons.io.output.ByteArrayOutputStream;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * Created by wucongpeng on 2017/6/11.
 */
public class DownLoadUtil {

 /**
 * 生成并下载二维码
 * @param url 二维码对于URL
 * @param width 二维码宽
 * @param height 二维码高
 * @param format 二维码格式
 * @return
 * @throws WriterException
 * @throws IOException
 */
 public static ResponseEntity<byte[]> getResponseEntity(String url, String fileName, int width, int height, String format) throws WriterException, IOException {

// String fileName = url.substring(url.lastIndexOf('/') + 1);

 Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
 hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
 BitMatrix bitMatrix = new MultiFormatWriter().encode(url,
 BarcodeFormat.QR_CODE, width, height, hints);// 生成矩阵
 //将矩阵转为Image
 BufferedImage image = MatrixToImageWriter.toBufferedImage(bitMatrix);
 ByteArrayOutputStream out = new ByteArrayOutputStream();
 ImageIO.write(image, format, out);//将BufferedImage转成out输出流
 HttpHeaders headers = new HttpHeaders();
 headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
 headers.setContentDispositionFormData("attachment", new String(fileName.getBytes("utf-8"), "ISO8859-1"));
 return new ResponseEntity<byte[]>(out.toByteArray(),
 headers, HttpStatus.CREATED);
 }
}