src/util/QRCodeUtil.java

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package util;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
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;

public class QRCodeUtil {
	
	private static final int BLACK = 0xFF000000;
	private static final int WHITE = 0xFFFFFFFF;
	
	public static void genGR(String website, OutputStream output) throws WriterException, IOException {
		int width = 300;
		int height = 300;
		String format = "jpg";
        Hashtable<EncodeHintType, String> hints = new Hashtable<EncodeHintType, String>(); 
        //Hashtable hints = new Hashtable();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
		BitMatrix bm = new MultiFormatWriter().encode(website, BarcodeFormat.QR_CODE, width, height, hints);
		
		BufferedImage image = toImage(bm);
		ImageIO.write(image, format, output);	//把二维码写到response的输出流
	}

	private static BufferedImage toImage(BitMatrix bm) {
		int width = bm.getWidth();
		int height = bm.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, bm.get(x, y) ? BLACK : WHITE);
			}
		}
		return image;
	}

}