您可以使用InputStream从服务器获取文档到本地计算机，并使用InputStream从文件中提取内容。

试试这个

Session session = null;
ChannelExec channel = null;
try {
  session = new JSch().getSession(username, host, port);
  session.setPassword(password);
  session.setConfig("StrictHostKeyChecking", "no");
  session.connect();

  channel = (ChannelExec) session.openChannel("exec");
  channel.setCommand("cat /home/user/a-file.txt");
  ByteArrayOutputStream responseStream = new ByteArrayOutputStream();
  channel.setOutputStream(responseStream);
  channel.connect();

  while (channel.isConnected()) {
    Thread.sleep(100);
  }
  
  //THIS IS FILE CONTENT
  byte[] content = responseStream.toByteArray();
} catch (Exception e) {
  throw new RuntimeException(e);
} finally {
  if (session != null) {
    session.disconnect();
  }
  if (channel != null) {
    channel.disconnect();
  }
}