我正在尝试使用内部使用jsch的vfs2连接器连接到SFTP主机。但是，当我尝试连接时，出现以下异常：
12:50:31.747 INFO o.a.c.v.p.sftp.SftpClientFactory - Connecting to <host> port <port>
12:50:32.074 INFO o.a.c.v.p.sftp.SftpClientFactory - Connection established
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - Remote version string: SSH-2.0-OpenSSH_7.4
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - Local version string: SSH-2.0-JSCH-0.1.54
12:50:32.376 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckCiphers: aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc,3des-ctr,arcfour,arcfour128,arcfour256
12:50:33.489 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckKexes: diffie-hellman-group14-sha1,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521
12:50:34.192 INFO o.a.c.v.p.sftp.SftpClientFactory - CheckSignatures: ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - SSH_MSG_KEXINIT sent
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - SSH_MSG_KEXINIT received
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],diffie-hellman-group-exchange-sha256
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-ed25519
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],aes128-cbc,aes192-cbc,aes256-cbc,blowfish-cbc,cast128-cbc,3des-cbc
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],[email protected],[email protected]
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: [email protected],[email protected],[email protected]
12:50:34.203 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: none,[email protected]
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server: none,[email protected]
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: server:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-ctr,aes192-cbc,aes256-ctr,aes256-cbc
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-ctr,aes192-cbc,aes256-ctr,aes256-cbc
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: none
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client: none
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client:
12:50:34.204 INFO o.a.c.v.p.sftp.SftpClientFactory - kex: client:
12:50:34.205 INFO o.a.c.v.p.sftp.SftpClientFactory - Disconnecting from <host> port <port>
12:50:34.243 ERROR c.s.saw.export.SFTPUploader - IO SFTP Error:
org.apache.commons.vfs2.FileSystemException: Could not connect to SFTP server at "sftp://<user>@<host>:<port>/".
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.createSession(SftpFileProvider.java:72)
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.doCreateFileSystem(SftpFileProvider.java:93)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.getFileSystem(AbstractOriginatingFileProvider.java:93)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:72)
at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:56)
at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:717)
at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:654)
at com.synchronoss.saw.export.SFTPUploader.uploadFile(SFTPUploader.java:99)
at com.synchronoss.saw.export.SFTPUploader.main(SFTPUploader.java:134)
Caused by: org.apache.commons.vfs2.FileSystemException: Could not connect to SFTP server at "<host>".
at org.apache.commons.vfs2.provider.sftp.SftpClientFactory.createConnection(SftpClientFactory.java:163)
at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.createSession(SftpFileProvider.java:65)
... 8 common frames omitted
Caused by: com.jcraft.jsch.JSchException: Algorithm negotiation fail
at com.jcraft.jsch.Session.receive_kexinit(Session.java:590)
at com.jcraft.jsch.Session.connect(Session.java:320)
at com.jcraft.jsch.Session.connect(Session.java:183)
at org.apache.commons.vfs2.provider.sftp.SftpClientFactory.createConnection(SftpClientFactory.java:161)
... 9 common frames omitted
我提到了一些博客和stackoverflow链接，并尝试了多种方法。我仍然没有获得任何成功的结果。另外，尝试了多个版本的vfs2和jsch，但无济于事。
以下是我引用的一些链接：
JSchException: Algorithm negotiation fail
JSch Algorithm negotiation fail
https://dzone.com/articles/install-java-cryptography-extension-jce-unlimited
The cipher 'aes256-cbc' is required, but it is not available
有人可以帮我吗？
您的服务器仅支持这些MAC：
[email protected],[email protected],[email protected]
JSch不支持这些。
如果需要与JSch连接，则必须将服务器配置为允许JSch支持的某些MAC：
hmac-md5,hmac-sha1,hmac-sha2-256,hmac-sha1-96,hmac-md5-96
使用MACs directive in sshd_config。
尽管MACs和sshd_config可能只是别名。因此，适当地配置JSch可能也会有所帮助：
hmac-sha2-*[email protected]但是我不确定，vfs2接口是否允许这种配置。