Apache Commons VFS - 无法解析文件

Question

The VFS method cannot process this URI ${jboss.server.temp.dir}/local/outgoing configured in jboss-beans.xml which is resolved to "C:\\\\Download\\\\jboss-eap-5.1.1\\\\server\\\\default\\\\tmp/local/outgoing" by JBoss. When I try to resolve the URI and get the file, it throws an exception. Any ideas what could be the problem?

Exception

17:35:25,024 ERROR [VfsSynchronizerConfImpl] File FromOutgoing cannot be resolved, FileSystemException:
org.apache.commons.vfs2.FileSystemException: Could not find file with URI "C:\Download\jboss-eap-5.1.1\server\default\tmp/local/outgoing" because it is a relative path, and no base URI was provided.
    at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:719)
    at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:649)
    at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:605)

DefaultFileSystemManager.class methods

public FileObject resolveFile(final String uri) throws FileSystemException
  -- this method calls the method below

public FileObject resolveFile(final FileObject baseFile, final String uri,
        final FileSystemOptions fileSystemOptions)
        throws FileSystemException
  -- this method cannot process the string and throws
     throw new FileSystemException("vfs.impl/find-rel-file.error", uri);

Answer 1

Quite old question but popular. This exception is quite generic. For my case, this exception was thrown while uploading files to remote ftp server. And the root cause was missing sftp library in classpath. Just before this exception, vfs tries to resolve the file using one of the provider corresponding to the scheme mentioned in URI .

For my case, scheme was sftp and and it tried to find jsch library on classpath. Since, it was not present on my classpath, this exception was thrown.Therefore, one must keep the provider jar on classpath.

Answer 2

For other people facing with this issue: I got rid of this error by replacing

FileSystemManager fsManager = VFS.getManager();

with

StandardFileSystemManager fsManager = new StandardFileSystemManager();
fsManager.init();

This allowed me to use the file system manager multiple times without getting the error anymore described in the question. Don't forget to close you fsManager when you're done with it:

fsManager.close();

Answer 3

@Manish Bansal - thank you for your reply on this issue. I tried everything but was still getting the same error: exception in thread "main" org.apache.commons.vfs2.filesystemexception: could not find file with uri "sftp://....." because it is a relative path, and no base uri was provided.

In my MAVEN project i had to add the dependency for 'jsch' & it worked.

So, in a nutshell i added the following POM dependencies:

<!-- SFTP -->
<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>   version>0.1.55</version>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-vfs2</artifactId>
    <version>2.6.0</version>
</dependency>

    public void downloadFile() throws IOException {     
        FileSystemManager manager = VFS.getManager();
                
        FileObject remote = manager.resolveFile(createConnectionString("XYZ.com","ABC","LMNOP","/<FOLDER_NAME>/<FILE_NAME>"));
        FileObject local = manager.resolveFile(System.getProperty("user.dir") + "/" + "src//main//resources//");
        
        local.copyFrom(remote, Selectors.SELECT_SELF);
     
        local.close();
        remote.close();
    }
    
    public static URI createConnectionString(String hostName, String username, String password, String remoteFilePath) {        
        URI sftpURI = null;
        try {
            String userInfo = username + ":" + password;
            
            sftpURI = new URI("sftp",userInfo,hostName,-1,remoteFilePath,null,null);
        } catch (URISyntaxException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return sftpURI;
    }

Answer 4

我认为它需要 file: 方案，因为错误表明它被认为是相对的。

Answer 5

Just to try to complement correct answers already provided.
In short : check VFS Dependencies Table for VFS features you use.

---

I ran into a similar problem when I first tried to connect over FTP ( not SFTP as in the original question ). I use Maven with IntelliJ IDEA.
I looked through the VFS official docs and found out the following:

1. Some of VFS Project Dependencies are optional and not installed by default .
2. What one can need to install is on the table in VFS Download & Build page .
   Indeed, JSch is required for SFTP , Apache Commons Net is required for FTP , etc.

My FTP connection had begun work as soon as I installed Commons Net via Maven.