将itext pdf另存为blob，但不存在. [英] Save itext pdf as blob without physical existence.

问题描述

我正在使用此代码使用iText生成PDF.首先，它将HTML创建为PDF，然后将其转换为字节数组，BLOB或字节数组. 我不想在服务器上创建pdf的任何物理存储.首先，我想使用itext将HTML转换为PDF的blob，然后，我要将那个blob存储在我的DB中(我将完成在DB中的存储).

I am using this code to generate PDF using iText. First it creates HTML to PDF after that it converts that PDF in byte array or in BLOB or in byte array. I dont want to create any physical stores of pdf on my server. First i want to convert HTML to blob of PDF using itext, And after that i want to store that blob in my DB(Stores in DB i will done).

          String userAccessToken=requests.getSession()
                    .getAttribute("access_token").toString();
          Document document = new Document(PageSize.LETTER);
          String name="/pdf/invoice.pdf";
          PdfWriter pdfWriter = PdfWriter.getInstance
               (document, new FileOutputStream(requests.getSession().getServletContext().getRealPath("")+"/assets"+name));
          document.open();
          document.addAuthor("Real Gagnon");
          document.addCreator("Real's HowTo");
          document.addSubject("Thanks for your support");
          document.addTitle("Please read this ");
          XMLWorkerHelper worker = XMLWorkerHelper.getInstance();

          //data is an html string 
          String str = data;
          worker.parseXHtml(pdfWriter, document, new StringReader(str));
          document.close();
          ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
          PdfWriter.getInstance(document, byteArrayOutputStream);
          byte[] pdfBytes = byteArrayOutputStream.toByteArray();

          link=name;
          System.out.println("Byte array is "+pdfBytes);

问题:-使用itext将html转换为pdf BLOB，而没有PDF的物理存在.

PROBLEM:- Convert html to pdf BLOB using itext, Without physical existence of PDF.

推荐答案

此问题的另一个答案几乎是正确的，但不完全正确.

The other answer to this question is almost correct, but not quite.

创建PdfWriter时可以使用任何OutputStream.如果要完全在内存中创建文件，则可以使用如下所示的ByteArrayOutputStream:

You can use any OutputStream when you create a PdfWriter. If you want to create a file entirely in memory, you can use a ByteArrayOutputStream like this:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
Document document = new Document();
PdfWriter.getInstance(document, baos);
document.open();
// add stuff
document.close();
byte[] pdf = baos.toByteArray();

简而言之:首先创建一个ByteArrayOutputStream，然后将此OutputStream传递给PdfWriter，然后在关闭文档后，可以从OutputStream获取字节.

In short: you first create a ByteArrayOutputStream, you pass this OutputStream to the PdfWriter and after the document is closed, you can get the bytes from the OutputStream.

(在另一个答案中，没有办法检索字节.而且:重要的是，不要在关闭文档之前尝试检索字节.)

(In the other answer, there was no way to retrieve the bytes. Also: it is important that you don't try to retrieve the bytes before the document is closed.)

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