Java中PDF文件的密码保护
There are different security levels that you can provide to your confidential documents. You can apply watermarks, encrypt files, or you can make your documents password-protected. In this article, we will see how to programmatically add password protection to the PDF files within the Java applications. Further, we will learn to change the password and also to remove the passwords to unlock PDF files. 本文讨论了以下主题：
- 用于 PDF 文件密码保护的 Java API *用Java密码保护PDF文件 * 在 Java 中更改 PDF 密码 * 如何删除 PDF 密码 - 解锁 PDF