阿里雲OSS下載pdf文件,並在pdf文件上添加水印

代碼: 兵馬未動,糧草先行

作者: 傳說中的汽水槍

如有錯誤,請留言指正,歡迎一起探討.

轉載請注明出處.

 

公司要求從阿里雲OSS下載pdf文件並且需要添加水印.

因此這里總結一下.

首先添加了一個FileUploadUtil.java文件:

    /**OSSClient*/
    private static OSSClient CLIENT;

    public static InputStream getInputStreamFromOSS(String ossFileName) {
        String parentDirectory = ossFileName.substring(0, 8) + "/";
        String fileId = "你自己的fileId";
        CLIENT = new OSSClient(ENDPOINT, ACCESSKEYID, ACCESSKEYSECRET);
        OSSObject ossObject = CLIENT.getObject(BUCKETNAME, fileId + ossFileName);
        InputStream inputStream = ossObject.getObjectContent();
        return inputStream;
    }

    public static void clientShutdown() {
        if (CLIENT != null) {
            CLIENT.shutdown();
        }
    }

在controller層先實現下載文件功能:

    @ResponseBody
    @RequestMapping(value = "/downloadFromOSS", method = RequestMethod.GET)
    public void downloadFromOSS(String fileName, HttpServletResponse response, HttpServletRequest request) {
        try {
            String dataString = DateUtil.date2Str(new Date(), "yyyy-MM-dd-HH-mm-ss-SSS");
            String destFileName = dataString + ".pdf";
            response.setCharacterEncoding("utf-8");
            response.setContentType("multipart/form-data");
            response.setHeader("Content-Disposition", "attachment;fileName=" + destFileName);
            // 獲取outputStream
            OutputStream outputStream = response.getOutputStream();
            // 獲取inputStream
            InputStream inputStream = FileUploadUtil.getInputStreamFromOSS(fileName);
            // 下載文件
            byte[] bytes = new byte[2048];
            int length;
            while ((length = inputStream.read(bytes)) > 0) {
                outputStream.write(bytes, 0, length);
            }
            outputStream.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            FileUploadUtil.clientShutdown();
        }
    }

實現下載並添加水印:

    @ResponseBody
    @RequestMapping(value = "/downloadWatermarkFile", method = RequestMethod.GET)
    public void downloadWatermarkFile(String fileName, HttpServletResponse response, HttpServletRequest request) {
        try {
            String dataString = DateUtil.date2Str(new Date(), "yyyy-MM-dd-HH-mm-ss-SSS");
            String destFileName = dataString + ".pdf";
            response.setCharacterEncoding("utf-8");
            response.setContentType("multipart/form-data");
            response.setHeader("Content-Disposition", "attachment;fileName=" + destFileName);
            // 獲取outputStream
            OutputStream outputStream = response.getOutputStream();
            // 獲取inputStream
            InputStream inputStream = FileUploadUtil.getInputStreamFromOSS(fileName);

            // 添加水印的時候,就已經在outputStream寫入了
            PdfReader reader = new PdfReader(inputStream);
            PdfStamper stamper = new PdfStamper(reader, outputStream);
            int total = reader.getNumberOfPages() + 1;
            PdfContentByte content;
            BaseFont base = BaseFont.createFont("STSongStd-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
            PdfGState gs = new PdfGState();
            for (int i = 1; i < total; i++) {
                content = stamper.getOverContent(i);// 在內容上方加水印
                //content = stamper.getUnderContent(i);//在內容下方加水印
                gs.setFillOpacity(0.2f);
                content.setGState(gs);
                content.beginText();
                content.setColorFill(com.itextpdf.text.BaseColor.LIGHT_GRAY);
                content.setFontAndSize(base, 50);
                content.setTextMatrix(70, 200);
                //將文字顯示在pdf頁面中
                // content.showTextAligned(Element.ALIGN_CENTER, "國際財富管理協會（中國）！", 300,350, 55);
                //設置文字顏色
                content.setColorFill(com.itextpdf.text.BaseColor.BLACK);
                //設置文字大小
                content.setFontAndSize(base, 8);
                //將內容顯示在pdf底部
                String waterMarkName = "111111";
                content.showTextAligned(Element.ALIGN_CENTER, "下載時間：" + waterMarkName + "", 300, 10, 0);
                content.endText();
            }
            stamper.close();
            outputStream.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            FileUploadUtil.clientShutdown();
        }
    }

 

OK 解決問題.