java生成二维码打印到浏览器
解决方法：
pom.xml的依赖两个jar包：
<!-- https://mvnrepository.com/artifact/com.google.zxing/core -->
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>core</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>com.google.zxing</groupId>
<artifactId>javase</artifactId>
<version>3.2.1</version>
</dependency>
源码：
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 com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
String payurl = "weixin://wxpay/bizpayur?";
//生成二维码
Map<EncodeHintType, Object> hints=new HashMap<EncodeHintType, Object>();
// 指定纠错等级
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);
// 指定编码格式
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
hints.put(EncodeHintType.MARGIN, 1);
BitMatrix bitMatrix = new MultiFormatWriter().encode(payurl,BarcodeFormat.QR_CODE, defaultWidthAndHeight, defaultWidthAndHeight, hints);
OutputStream out = response.getOutputStream();
MatrixToImageWriter.writeToStream(bitMatrix, "png", out);//输出二维码
out.flush();
out.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}