maven配置

      <dependency>
            <groupId>com.google.zxing</groupId>
            <artifactId>javase</artifactId>
            <version>3.0.0</version>
        </dependency>

java代码
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

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;

public abstract class QRCodeUtil
{
    public static void getQRCode(String url, OutputStream os)
    {
        int width = 200;
        int height = 200;
        String format = "png";
        Map<EncodeHintType, Object> hints = new HashMap<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        hints.put(EncodeHintType.MARGIN, 1);
        try
        {
            BitMatrix bitMatrix = new MultiFormatWriter().encode(url,
                    BarcodeFormat.QR_CODE, width, height, hints);
            MatrixToImageWriter.writeToStream(bitMatrix, format, os);
        }
        catch (WriterException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

}

java生二维码