Apache CommonsVFS connect to https server

Currently I use Apache CommonsVFS to fetch images from other sites and it works well.

The website of CommonsVFS says it supports HTTPS protocol, but I found I could not access those URL starts with https:// using CommonVFS, while I could browse it from my Firefox normally.

For example, the following code will yield an exception says could not connect to HTTP server..

scala> import org.apache.commons.vfs.VFS                                                  
import org.apache.commons.vfs.VFS

scala> val fsManager = VFS.getManager();
fsManager: org.apache.commons.vfs.FileSystemManager = org.apache.commons.vfs.impl.StandardFileSystemManager@16a0733

scala> val file1 = fsManager.resolveFile ("http://bone.twbbs.org.tw/Images/desk.jpg")
file1: org.apache.commons.vfs.FileObject = http://bone.twbbs.org.tw/Images/desk.jpg

scala> val file2 = fsManager.resolveFile ("https://na.archives.gov.tw/archives/chinese/98/search/popup.jsp?res=/export/home/xdcm/do/ScaleDoFiles/jpg/00/00/01/21/07/A313480000K=0089=577=1=1=003=0002-i.jpg")
org.apache.commons.vfs.FileSystemException: Could not connect to HTTP server on "na.archives.gov.tw".
    at org.apache.commons.vfs.provider.http.HttpClientFactory.createConnection(HttpClientFactory.java:105)
    at org.apache.commons.vfs.provider.http.HttpFileProvider.doCreateFileSystem(HttpFileProvider.java:81)
    at org.apache.commons.vfs.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:81)
    at org.apache.commons.vfs.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:62)
    at org.apache.commons.vfs.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:641)
    at org.apache.commons.vfs.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:602)
    at org.apache.commons.vfs.impl.DefaultFileS...

I also tried to add HTTPS provider for FileManager, but still has no luck, it says URL scheme "https" is already registered.

scala> fsManager.asInstanceOf[org.apache.commons.vfs.impl.StandardFileSystemManager].addProvider("https", new org.apache.commons.vfs.provider.https.HttpsFileProvider)
org.apache.commons.vfs.FileSystemException: Multiple providers registered for URL scheme "https".
    at org.apache.commons.vfs.impl.DefaultFileSystemManager.addProvider(DefaultFileSystemManager.java:174)
    at org.apache.commons.vfs.impl.DefaultFileSystemManager.addProvider(DefaultFileSystemManager.java:152)
    at .<init>(<console>:8)
    at .<clinit>(<console>)
    at RequestResult$.<init>(<console>:9)
    at RequestResult$.<clinit>(<console>)
    at RequestResult$scala_repl_resul开发者_JS百科t(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at scala.tools.nsc.Interpr...

So, how could I use commonVFS to access https server?

OK, I found out that it throws this exception because the certificate of the site which I try to connected is not trusted in my Java keystore.

I followed the instruction here to add the certificate to my keystore, and everything works fine now.