package com.xiaojiezhu.util;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;

import java.io.OutputStream;

import javax.imageio.ImageIO;

import com.google.zxing.common.BitMatrix;

 public final class MatrixToImageWriter {

   private static final int BLACK = 0xFF000000;

   private static final int WHITE = 0xFFFFFFFF;

   private MatrixToImageWriter() {}

   /**

    * 把BitMatrix类中的对象，转换成一个二维码图片

    * @param matrix

    * @return

    */

   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;

   }

   /**

    * 把二维码保存至文件

    * @param matrix

    * @param format

    * @param file

    * @throws IOException

    */

   public static void writeToFile(BitMatrix matrix, String format, File file)

       throws IOException {

     BufferedImage image = toBufferedImage(matrix);

     if (!ImageIO.write(image, format, file)) {

       throw new IOException("Could not write an image of format " + format + " to " + file);

     }

   }

   /**

    * 把二维码保存至流对象

    * @param matrix

    * @param format

    * @param stream

    * @throws IOException

    */

   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);

     }

   }

 }

public static void main(String[] args) {

        try {

            //这个内容可以是网址，也可以是一段文字，如果是网址，就会跳转至此网址。如果是文字，就会直接显示文字内容

             String content = "https://www.baidu.com";

             //这个是保存的路径，当然，工具类中有一个重载的方法，也就是直接保存到流中，也就是一个outputstream

             String path = "d:/";

             MultiFormatWriter multiFormatWriter = new MultiFormatWriter();

             Map<EncodeHintType,String> hints = new HashMap<EncodeHintType,String>();

             //设置编码

             hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");

             //第一个参数是内容，或者网址，第二个参数是生成的类型，当前类型是二维码，也可以是条形码，后面是长度宽度，最后是声明的参数map

             BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 400, 400,hints);

             File file1 = new File(path,"餐巾纸.jpg");

             //使用此方法保存至文件中

             MatrixToImageWriter.writeToFile(bitMatrix, "jpg", file1);

             //使用此方法保存至输出流中

             MatrixToImageWriter.writeToStream(bitMatrix, "jpg", new FileOutputStream(""));

         } catch (Exception e) {

             e.printStackTrace();

         }

    }