二维码扫描已是时下非常常用的分享、推广的方式，Google的zxing是一个很好用的二维码工具包，本文分享如何使用zxing生成自定义的二维码。
tips：开发工具IntelliJ IDEA

1. 新建MAVEN工程
2. pom.xml 新增zxing和junit依赖

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.3.0</version>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>

3.实现二维码功能逻辑

    /**
     * 生成二维码图片
     * @param content 二维码内容
     * @param width 宽
     * @param height 高
     * @param margin 二维码外边距，0到4
     * @param imgPath 二维码图片存放路径
     */
    public void createQRCode(String content,int width,int height,int margin,String imgPath) throws WriterException, IOException {
        /**二维码参数设定*/
        Hashtable<EncodeHintType,Object> hintTypes = new Hashtable<EncodeHintType, Object>();
        hintTypes.put(EncodeHintType.CHARACTER_SET,CharacterSetECI.UTF8);
        hintTypes.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);//容错级别，共4级，详细问度娘
        hintTypes.put(EncodeHintType.MARGIN,margin);//二维码外边距

        BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE,width,height,hintTypes);//创建二维码，本质为二位数组

/**将二维码转为图片*/
        BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        for (int i = 0; i < width; i++) {
            for (int j = 0; j < height; j++) {
                bufferedImage.setRGB(i,j,bitMatrix.get(i,j)? Color.BLACK.getRGB():Color.WHITE.getRGB());
            }
        }

        File imageFile = new File(imgPath+"myQRCode.png");
        if (!imageFile.getParentFile().exists()){
            imageFile.getParentFile().mkdirs();
        }
        ImageIO.write(bufferedImage,"png",imageFile);
    }
    
    /**
     * 生成二维码图片字节数组，可将字节数组写入文件、经base64编码后写入FreeMarker模版等操作
     * @param content 二维码内容
     * @param width 宽
     * @param height 高
     * @param margin 外边距
     * @return 二维码对应的字节数组
     * @throws Exception
     */
    public byte[] getQRCodeBytes(String content,int width,int height,int margin) throws Exception{
        Hashtable<EncodeHintType,Object> hintTypes = new Hashtable<EncodeHintType, Object>();
        ByteArrayOutputStream outputStream = null;

        hintTypes.put(EncodeHintType.CHARACTER_SET,CharacterSetECI.UTF8);//设置编码
        hintTypes.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);//设置容错级别
        hintTypes.put(EncodeHintType.MARGIN,margin);//设置外边距

        try {
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE,width,height,hintTypes);//获取二维码

            //将二维码写入图片
            BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
            for (int i = 0; i < width; i++) {
                for (int j = 0; j < height; j++) {
                    bufferedImage.setRGB(i,j,bitMatrix.get(i,j)? Color.RED.getRGB():Color.WHITE.getRGB());
                }
            }

            //将图片转为字节数组
            outputStream = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage,"png",outputStream);
            return outputStream.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        } finally {
            if (outputStream != null){
                outputStream.close();
            }
        }
    }

4.好了，代码码完了，测试一波

 @Test
    public void testCreateDefaultQRCode() throws IOException, WriterException {
        QRCodeService service = new QRCodeService();
        service.createQRCode("hello world",300,300,"./");
    }

    @Test
    public void testGetQRCodeBytes() throws Exception {
        QRCodeService service = new QRCodeService();
        byte[] bytes = service.getQRCodeBytes("https://www.runoob.com",500,500,1);

        FileUtils.writeByteArrayToFile(new File("我的二维码.png"),bytes,true);
    }

• FileUtils为Apache的开源工具包
• 以上源码可在GitHub上查看下载，点击查看