Java生成二维码并存储到MongoDB数据库中（或本地中）

【实现】

首先两个辅助方法：（来自MatrixToImageWriter类，该类是由Google提供的，可以将方法直接拷贝到代码中使用）

1. toBufferedImage

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;
	}

注：

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

2. writeToStream

public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {
		BufferedImage image = toBufferedImage(matrix);
		if (!ImageIO.write(image, format, stream)) {
			throw new IOException("Could not write an image of format " + format);
		}
	}

然后具体实现方法：

1.生成二维码并存到本地

   public static void main(String[] args) {
		String contents = "Java生成二维码，并存到本地。";
		int width = 430;
		int height = 430;
		String format = "gif";
		Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
		hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
		hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
		hints.put(EncodeHintType.MARGIN, 1);
		try {
			BitMatrix bitMatrix = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE, width, height, hints);
			File outputFile = new File("D:" + File.separator + "myqrcode.gif");
			BufferedImage image = toBufferedImage(bitMatrix);
			if (!ImageIO.write(image, format, outputFile)) {
				throw new IOException(format + " not to " + outputFile);
			}
		} catch (WriterException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

效果

2.生成二维码并存到MongoDB数据库

public void testCreateQrCode() {
		String contents = "Java生成二维码，并存到MongoDB数据库。";
		int width = 430;
		int height = 430;
		String format = "png";
		Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
		hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
		hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
		hints.put(EncodeHintType.MARGIN, 1);
		try {
			BitMatrix bitMatrix = new MultiFormatWriter().encode(contents, BarcodeFormat.QR_CODE, width, height, hints);
			BufferedImage image = toBufferedImage(bitMatrix);
			ByteArrayOutputStream os = new ByteArrayOutputStream();
			ImageIO.write(image, format, os);
			byte b[] = os.toByteArray();
			grouponDAO.test(b, "5c404615166a7c081c906b40");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (WriterException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

效果

最后引用的包：

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Hashtable;

import javax.imageio.ImageIO;

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;

生成二维码的方法还有有很多种，这个是本人觉得相对较简单的方式，其他就不赘述了。

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