/**
  * 获取连接
  * @param ip 跳转机host
  * @param userName 跳转机用户名
  * @param pwd 跳转机密码
  * @param port 跳转机端口
  * @return ChannelSftp 返回值
  * @throws JSchException 连接异常
  */
 public static ChannelSftp connect(String ip, String userName, String pwd, int port) throws JSchException
 {
  if (port <= 0)
  {
   port = PORT;
  }
  Session sshSession = null;
  JSch jsch = new JSch();
  sshSession = jsch.getSession(userName, ip, port);
  
  sshSession.setPassword(pwd);
  Properties sshConfig = new Properties();
  sshConfig.put("StrictHostKeyChecking", "no");
  sshConfig.put("PreferredAuthentications",
    "password,keyboard-interactive");
  sshSession.setConfig(sshConfig);
  
  
  sshSession.connect(TMOUT);//可设置超时时间 
  //此处开始为端口映射到本地的部分
  sshSession.setPortForwardingL(本地端口, 目标节点地址, 22);
  //完成上诉映射之后，即可通过本地端口连接了
  Session session = jsch.getSession("目标服务用户名", "127.0.0.1",本地端口);
  Properties remoteCfg = new Properties();
  remoteCfg.put("StrictHostKeyChecking", "no");
  remoteCfg.put("PreferredAuthentications",
    "password,keyboard-interactive");
  session.setConfig(remoteCfg);
  session.setPassword("目标服务密码");
  session.connect();
  //后续如何可自行改变，网上运用很多
  Channel channel = (Channel) session.openChannel("sftp");//创建sftp通信通道 
  channel.connect();
  ChannelSftp sftp = (ChannelSftp) channel;
  
  return sftp;
 }