java poi 如何读取带密码的ppt ,求大神帮忙

java poi如何读取带密码的ppt,我知道密码 不知道如何用poi代码打开

有些算法密码是支持的,参考官方资料：
https://poi.apache.org/encryption.html

// RC4 CryptoApi support ppt - decryption
Biff8EncryptionKey.setCurrentUserPassword("pass");
NPOIFSFileSystem fs = new NPOIFSFileSystem(new File("file.ppt"), true);
HSLFSlideShow hss = new HSLFSlideShow(fs);

这是部分代码 打开不带密码的会了

private BufferedImage image;
private HSLFSlideShow pptSlide;
private List slides;
private Dimension pgsize;
private boolean imageFlag = false;
public Test(){
try {
File file = new File("ppt/bigfanyue.pptx");
FileInputStream fis = new FileInputStream(file);
pptSlide = new HSLFSlideShow(fis);
pptSlide.setPageSize(new Dimension(1024,768));
slides = pptSlide.getSlides();
maxPage = slides.size();
pgsize = pptSlide.getPageSize();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}