java给图片加上水印

有时候我们需要给照片上传的时候，加一些水印。

public String watermarkMulText(InputStream is, String filename, String realUploadPath) {
        String logoFileName = System.currentTimeMillis()+filename.substring(filename.lastIndexOf("."));
        OutputStream os = null;

        try {
            Image image2 = ImageIO.read(is);
            int width = image2.getWidth(null);
            int height = image2.getHeight(null);

//            1、创建缓存图片对象
            BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

//            2、        创建JAVA绘图工具对象
            Graphics2D graphics2D = bufferedImage.createGraphics();

//            3、使用绘图工具对象，将原图绘制到缓存图片对象
            graphics2D.drawImage(image2,0,0,width,height,null);

//            4、使用绘图工具，将水印（文字/图片）绘制到缓存图片对象
            graphics2D.setFont(new Font(FONT_NAME,FONT_STYLE,FONT_SIZE));
            graphics2D.setColor(FONT_COLOR);

            //S1-获取文字水印的宽、高
            int width1 = FONT_SIZE*getTextLength(MARK_TEXT);
            int height1 = FONT_SIZE;


            graphics2D.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,ALPHA));//设置水印图层

            graphics2D.rotate(Math.toRadians(45),bufferedImage.getHeight()/2,bufferedImage.getHeight()/2);//图层以中心为基点，转30度的弧度。

            int x = -width/2;
            int y = -height/2;

            while (x<width*1.5){
                y = -height/2;
                while (y<height*1.5){
                    graphics2D.drawString(MARK_TEXT,x,y);
                    y+=height1+MARGIN_ALL;
                }
                x+=width1+MARGIN_ALL;
            }


            graphics2D.dispose();

//            5、        创建图像编码工具类
            String des = realUploadPath+File.separator+ logoFileName;
            os = new FileOutputStream(des);

            JPEGImageEncoder jpegImageEncoder = JPEGCodec.createJPEGEncoder(os);

//            6、使用图片编码工具类，输出缓存图像到模板图片文件
            jpegImageEncoder.encode(bufferedImage);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(os!=null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }


        return realUploadPath+File.separator+logoFileName;
    }

以上修改于网上的一段代码，忘记保留出处了。

效果如下：

String --> InputStream

ByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());
InputStream --> String
String inputStream2String(InputStream is){
	BufferedReader in = new BufferedReader(new InputStreamReader(is));
   StringBuffer buffer = new StringBuffer();
   String line = "";
   while ((line = in.readLine()) != null){
     buffer.append(line);
   }
   return buffer.toString();
}

File --> InputStream

InputStream in = new FileInputStream(file);

InputStream --> File

public void inputstreamtofile(InputStream ins,File file){
   OutputStream os = new FileOutputStream(file);
   int bytesRead = 0;
   byte[] buffer = new byte[8192];
   while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
      os.write(buffer, 0, bytesRead);
   }
   os.close();
   ins.close();

BufferedImage --> inputStream
BufferedImage --> String

public static InputStream encode(String content, String logoPath, boolean needCompress) throws Exception {
        BufferedImage image = QrCodeUtil.createImage(content, logoPath, true);
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ImageIO.write(image, FORMAT, outputStream);
        //String streamEncoded = Base64Util.encode(outputStream.toByteArray());
        InputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());
        return inputStream;
  }

转：https://blog.csdn.net/weixin_39248420/article/details/89949880