使用Java将pdf设置为密码保护 [英] making pdf as password protected with java

问题描述

我想制作一个现有的PDF作为密码保护，我正在使用它遵循此URL的itext

I want to make an existing PDF as password protected for which I'm using the itext I am following this URL

http://howtodoinjava.com/2014/07/29/create-pdf-files-in-java-itext-tutorial/

我已经开发了一个程序，该程序将发送带有PDF附件的邮件.下面是我将PDF文件设置为受密码保护的代码.

I have developed a program which will send the mail with the PDF as attachment. Below is the code where I am making the PDF file as password protected.

现在，该PDF文件已附加在邮件中，但是当我尝试打开它时，我收到一个错误，指出它已损坏.

Right now the PDF file is attached in mail but when I am trying to open it, I get an error that it is damaged.

我在下面的代码中怎么了?

What am I doing wrong in the code below?

//  attachment part
MimeBodyPart attachPart = new MimeBodyPart();
String filename = "c:\\SettingupRulesin outlook2003.pdf";

//OutputStream file = new FileOutputStream(new File("PasswordProtected.pdf"));
final OutputStream os = new FileOutputStream(filename);
com.itextpdf.text.Document doc = new com.itextpdf.text.Document();
PdfWriter writer = PdfWriter.getInstance(doc, os);
writer.setEncryption(USER_PASSWORD.getBytes(),
                     OWNER_PASSWORD.getBytes(), PdfWriter.ALLOW_PRINTING,
                     PdfWriter.ENCRYPTION_AES_128); 

os.close();


DataSource source = new FileDataSource(filename);
attachPart.setDataHandler(new DataHandler(source));
attachPart.setFileName(filename);

推荐答案

您使用 PdfWriter .该类可用于从头开始创建新的PDF，而不用操作现有的PDF.请改用 PdfStamper 来处理现有文档.

You use a PdfWriter. That class can be used to create new PDFs from scratch, not to manipulate existing ones. Please use a PdfStamper instead which is for manipulating existing documents.

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