Java常用工具類：生成二維碼base64編碼

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;

import javax.imageio.ImageIO;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Base64OutputStream;

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

public class QRcodeKitUtils {

	public static final String QRCODE_DEFAULT_CHARSET = "UTF-8";

	public static final int QRCODE_DEFAULT_HEIGHT = 150;

	public static final int QRCODE_DEFAULT_WIDTH = 150;

	private static final int BLACK = 0xFF000000;
	private static final int WHITE = 0xFFFFFFFF;

	public static void main(String[] args) throws Exception {
		// 生成不帶log的二維碼base64編碼測試
		BufferedImage bi = createQRCode("http://www.baidu.com");
		String base64Img = getImageBase64String(bi);
		System.err.println(base64Img);
	}

	public static String generateQRCode(String url) {
		try {
			String data = url;
			// logo圖片路徑(這是相對路徑)
			File logoFile = new File("img/logo.png");
			BufferedImage image = QRcodeKitUtils.createQRCodeWithLogo(data,
					logoFile);
			ByteArrayOutputStream os = new ByteArrayOutputStream();
			ImageIO.write(image, "png", os);
			Base64 base64 = new Base64();
			String base64Img = new String(base64.encode(os.toByteArray()));
			return base64Img;
		} catch (IOException e) {
			e.printStackTrace();
			return "http://store.10000pro.com/";
		}
	}

	/**
	 * Create qrcode with default settings
	 * 
	 * @author stefli
	 * @param data
	 * @return
	 */
	public static BufferedImage createQRCode(String data) {
		return createQRCode(data, QRCODE_DEFAULT_WIDTH, QRCODE_DEFAULT_HEIGHT);
	}

	/**
	 * Create qrcode with default charset
	 * 
	 * @author stefli
	 * @param data
	 * @param width
	 * @param height
	 * @return
	 */
	public static BufferedImage createQRCode(String data, int width, int height) {
		return createQRCode(data, QRCODE_DEFAULT_CHARSET, width, height);
	}

	/**
	 * Create qrcode with specified charset
	 * 
	 * @author stefli
	 * @param data
	 * @param charset
	 * @param width
	 * @param height
	 * @return
	 */
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public static BufferedImage createQRCode(String data, String charset,
			int width, int height) {
		Map hint = new HashMap();
		// hint.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
		// hint.put(EncodeHintType.CHARACTER_SET, charset);

		return createQRCode(data, charset, hint, width, height);
	}

	/**
	 * Create qrcode with specified hint
	 * 
	 * @author stefli
	 * @param data
	 * @param charset
	 * @param hint
	 * @param width
	 * @param height
	 * @return
	 */
	public static BufferedImage createQRCode(String data, String charset,
			Map<EncodeHintType, ?> hint, int width, int height) {
		BitMatrix matrix;
		try {
			matrix = new MultiFormatWriter().encode(
					new String(data.getBytes(charset), charset),
					BarcodeFormat.QR_CODE, width, height, null);
			return toBufferedImage(matrix);
		} catch (WriterException e) {
			throw new RuntimeException(e.getMessage(), e);
		} catch (Exception e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	public static BufferedImage toBufferedImage(BitMatrix matrix) {
		int width = matrix.getWidth();
		int height = matrix.getHeight();
		BufferedImage image = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		for (int x = 0; x < width; x++) {
			for (int y = 0; y < height; y++) {
				image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
			}
		}
		return image;
	}

	/**
	 * Create qrcode with default settings and logo
	 * 
	 * @author stefli
	 * @param data
	 * @param logoFile
	 * @return
	 */
	public static BufferedImage createQRCodeWithLogo(String data, File logoFile) {
		return createQRCodeWithLogo(data, QRCODE_DEFAULT_WIDTH,
				QRCODE_DEFAULT_HEIGHT, logoFile);
	}

	/**
	 * Create qrcode with default charset and logo
	 * 
	 * @author stefli
	 * @param data
	 * @param width
	 * @param height
	 * @param logoFile
	 * @return
	 */
	public static BufferedImage createQRCodeWithLogo(String data, int width,
			int height, File logoFile) {
		return createQRCodeWithLogo(data, QRCODE_DEFAULT_CHARSET, width,
				height, logoFile);
	}

	/**
	 * Create qrcode with specified charset and logo
	 * 
	 * @author stefli
	 * @param data
	 * @param charset
	 * @param width
	 * @param height
	 * @param logoFile
	 * @return
	 */
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public static BufferedImage createQRCodeWithLogo(String data,
			String charset, int width, int height, File logoFile) {
		Map hint = new HashMap();
		hint.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
		hint.put(EncodeHintType.CHARACTER_SET, charset);

		return createQRCodeWithLogo(data, charset, hint, width, height,
				logoFile);
	}

	/**
	 * Create qrcode with specified hint and logo
	 * 
	 * @author stefli
	 * @param data
	 * @param charset
	 * @param hint
	 * @param width
	 * @param height
	 * @param logoFile
	 * @return
	 */
	public static BufferedImage createQRCodeWithLogo(String data,
			String charset, Map<EncodeHintType, ?> hint, int width, int height,
			File logoFile) {
		try {
			BufferedImage qrcode = createQRCode(data, charset, hint, width,
					height);
			BufferedImage logo = ImageIO.read(logoFile);
			int deltaHeight = height - logo.getHeight();
			int deltaWidth = width - logo.getWidth();

			BufferedImage combined = new BufferedImage(height, width,
					BufferedImage.TYPE_INT_ARGB);
			Graphics2D g = (Graphics2D) combined.getGraphics();
			g.drawImage(qrcode, 0, 0, null);
			g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
					1f));
			g.drawImage(logo, (int) Math.round(deltaWidth / 2),
					(int) Math.round(deltaHeight / 2), null);

			return combined;
		} catch (IOException e) {
			throw new RuntimeException(e.getMessage(), e);
		} catch (Exception e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	/**
	 * Return base64 for image
	 * 
	 * @author stefli
	 * @param image
	 * @return
	 */
	public static String getImageBase64String(BufferedImage image) {
		String result = null;
		try {
			ByteArrayOutputStream os = new ByteArrayOutputStream();
			OutputStream b64 = new Base64OutputStream(os);
			ImageIO.write(image, "png", b64);
			result = os.toString("UTF-8");
		} catch (UnsupportedEncodingException e) {
			throw new RuntimeException(e.getMessage(), e);
		} catch (IOException e) {
			throw new RuntimeException(e.getMessage(), e);
		}
		return result;
	}

	/**
	 * Decode the base64Image data to image
	 * 
	 * @author stefli
	 * @param base64ImageString
	 * @param file
	 */
	public static void convertBase64StringToImage(String base64ImageString,
			File file) {
		FileOutputStream os;
		try {
			Base64 d = new Base64();
			byte[] bs = d.decode(base64ImageString);
			os = new FileOutputStream(file.getAbsolutePath());
			os.write(bs);
			os.close();
		} catch (FileNotFoundException e) {
			throw new RuntimeException(e.getMessage(), e);
		} catch (IOException e) {
			throw new RuntimeException(e.getMessage(), e);
		} catch (Exception e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

}

依賴jar包：com-google-zxing-core-3.1.0.jar

下載鏈接：https://pan.baidu.com/s/1pEhdQgXYc8jEyJLIuqqMew  提取碼：8ryz 

前端圖片標籤添加屬性：$("#QRImg").attr("src", "data:image/gif;base64," + response.data.imgBase64);