通過JSch - Java實現的SFTP

 JSch是Java Secure Channel的縮寫。JSch是一個SSH2的純Java實現。它允許你連接到一個SSH服務器，并且可以使用端口轉發，X11轉發，文件傳輸等，當然你也可以集成它的功能到你自己的應用程序。

  本文只介紹如何使用JSch實現的SFTP功能。

  SFTP是Secure File Transfer Protocol的縮寫，安全文件傳送協議。可以為傳輸文件提供一種安全的加密方法。SFTP 為 SSH的一部份，是一種傳輸文件到服務器的安全方式。SFTP是使用加密傳輸認證信息和傳輸的數據，所以，使用SFTP是非常安全的。但是，由于這種傳輸 方式使用了加密/解密技術，所以傳輸效率比普通的FTP要低得多，如果您對網絡安全性要求更高時，可以使用SFTP代替FTP。（來自百度的解釋） 

  要使用JSch，需要下載它的jar包，請從官網下載它：http://www.jcraft.com/jsch/

import java.io.FileNotFoundException;
import java.io.OutputStream;
import java.net.UnknownHostException;
import java.util.Properties;
import java.util.Vector;

import org.apache.commons.httpclient.auth.AuthenticationException;
import com.ebao.jewel.gs.integration.pub.CommonLog.exception.ExceptionUtil;
import com.ebao.jewel.gs.integration.pub.CommonLog.utils.JewelIntLogUtils;
import com.ebao.jewel.gs.integration.pub.commons.InterfaceUtil;
import com.ebao.jewel.gs.integration.pub.connection.IConnection;
import com.ebao.jewel.gs.integration.pub.constants.InterfaceConstants;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
public class JewelSftpClient implements IConnection {
private Session sshSession = null;
private ChannelSftp channelSftp = null;
private int connectTimes = 0;
public boolean connect(String host, int port, String username, String pwd)
throws Exception {
    if (sshSession == null || !sshSession.isConnected()) {

  JSch jsch = new JSch();

  try {
    sshSession = jsch.getSession(username, host, port);
  } catch (JSchException je) {
    // throw new Connection
    throw je;
  }
}
if (!sshSession.isConnected()) {
  InterfaceUtil.batchLog("[TEST] sshSession.connect()");
  sshSession.setPassword(pwd);

  Properties sshConfig = new Properties();
  sshConfig.put("StrictHostKeyChecking", "no");
  sshSession.setConfig(sshConfig);
  try {
    sshSession.connect();
  } catch (JSchException ex) {

    if (ex.getMessage().indexOf("Session.connect") != -1) {
      throw new UnknownHostException(ExceptionUtil.getExceptionMsg(ex));
    } else {
      throw new AuthenticationException(ExceptionUtil.getExceptionMsg(ex));
    }
  }
}
InterfaceUtil.batchLog("[TEST] sshSession has connected.");
try {
  if (channelSftp == null || !channelSftp.isConnected()) {
    InterfaceUtil.batchLog("[TEST] channelSftp.connect()");
    channelSftp = (ChannelSftp) sshSession.openChannel("sftp");
    channelSftp.connect();
  }

  InterfaceUtil.batchLog("[TEST] channelSftp has been established.");
  return true;
} catch (JSchException je) {
  if (connectTimes++ < InterfaceConstants.MAX_CONNECT_TIMES) {
    String seq = connectTimes == 1 ? "1st" : connectTimes == 2
        ? "2nd"
        : connectTimes == 3 ? "3rd" : connectTimes + "st";
    InterfaceUtil.batchLog("[TEST]" + seq
        + " connection failed. Disconnected "
        + (disconnect() == true ? "succeeded" : "failed"));
    long sleepTime = InterfaceUtil.getConnectSleepTime() * 1000L;
    Thread.sleep(sleepTime);
    InterfaceUtil.batchLog("[TEST]" + sleepTime + " ms passed. Try "
        + (int) (connectTimes + 1) + " connection.");
    if (connectTimes == 4) {
      InterfaceUtil
          .batchLog("[TEST] !!!!!!!!!!!connection goes wrong!!!!!!!!!!!!!!!!");
    }
    return connect(host, port, username, pwd);
  } else {
    InterfaceUtil.batchLog("[TEST] connect excceeded 10 times.");
    throw je;
  }
}

}
public boolean disconnect() throws Exception {
    try {
      if (channelSftp != null && channelSftp.isConnected()) {

    channelSftp.disconnect();
    InterfaceUtil.batchLog("[TEST] channelSftp has cloesd.");
  }
  if (sshSession != null && sshSession.isConnected()) {

    sshSession.disconnect();
    InterfaceUtil.batchLog("[TEST] sshSession has cloesd.");
  }
  return true;
} catch (Exception e) {
  return false;

}


}
public void upload(String src, String dst) throws Exception {
    channelSftp.put(src, dst);
  }
public void download(String src, String dst) throws Exception {
    channelSftp.get(src, dst);
}
@SuppressWarnings("unchecked")
  public Vector<Object> listFiles(String directory) throws Exception {
    try {
      channelSftp.cd(directory);
    } catch (Exception e) {
      throw new FileNotFoundException("No such file or directory.src:"

      + directory);
}
Vector<Object> files = channelSftp.lsnames(directory);
return files;


}
public boolean moveFile(String src, String dst) throws Exception {
    try {
      channelSftp.rename(src, dst);
      return true;
    } catch (Exception e) {
      JewelIntLogUtils.batchLog("[TEST] Move the file from " + src + " to "

      + dst + " fail", e);
  throw e;
}

}
public boolean isConnected() {
    return channelSftp != null && channelSftp.isConnected();
  }
@Override
  public void download(String src, OutputStream out) throws Exception {
    channelSftp.get(src, out);
  }
}</pre>