如何通过 SFTP 从服务器检索文件？

Question

我正在尝试使用 Java 使用 SFTP（而不是 FTPS）从服务器检索文件。我该怎么做？

Answer 1

另一种选择是考虑查看JSch library。 JSch 似乎是一些大型开源项目的首选库，包括 Eclipse、Ant 和 Apache Commons HttpClient 等。

它很好地支持用户/密码和基于证书的登录，以及所有其他美味的 SSH2 功能。

这是一个通过 SFTP 检索的简单远程文件。错误处理留给读者练习:-)

JSch jsch = new JSch();

String knownHostsFilename = "/home/username/.ssh/known_hosts";
jsch.setKnownHosts( knownHostsFilename );

Session session = jsch.getSession( "remote-username", "remote-host" );    
{
  // "interactive" version
  // can selectively update specified known_hosts file 
  // need to implement UserInfo interface
  // MyUserInfo is a swing implementation provided in 
  //  examples/Sftp.java in the JSch dist
  UserInfo ui = new MyUserInfo();
  session.setUserInfo(ui);

  // OR non-interactive version. Relies in host key being in known-hosts file
  session.setPassword( "remote-password" );
}

session.connect();

Channel channel = session.openChannel( "sftp" );
channel.connect();

ChannelSftp sftpChannel = (ChannelSftp) channel;

sftpChannel.get("remote-file", "local-file" );
// OR
InputStream in = sftpChannel.get( "remote-file" );
  // process inputstream as needed

sftpChannel.exit();
session.disconnect();

Answer 2

这里是使用JSch 的示例的完整源代码，无需担心 ssh 密钥检查。

import com.jcraft.jsch.*;

public class TestJSch {
    public static void main(String args[]) {
        JSch jsch = new JSch();
        Session session = null;
        try {
            session = jsch.getSession("username", "127.0.0.1", 22);
            session.setConfig("StrictHostKeyChecking", "no");
            session.setPassword("password");
            session.connect();

            Channel channel = session.openChannel("sftp");
            channel.connect();
            ChannelSftp sftpChannel = (ChannelSftp) channel;
            sftpChannel.get("remotefile.txt", "localfile.txt");
            sftpChannel.exit();
            session.disconnect();
        } catch (JSchException e) {
            e.printStackTrace();  
        } catch (SftpException e) {
            e.printStackTrace();
        }
    }
}

Answer 3

以下是使用 Apache Common VFS 的示例：

FileSystemOptions fsOptions = new FileSystemOptions();
SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(fsOptions, "no");
FileSystemManager fsManager = VFS.getManager();
String uri = "sftp://user:password@host:port/absolute-path";
FileObject fo = fsManager.resolveFile(uri, fsOptions);

Answer 4

在 Jsch 之上的一个很好的抽象是 Apache commons-vfs，它提供了一个虚拟文件系统 API，使得访问和写入 SFTP 文件几乎是透明的。对我们来说效果很好。

Answer 5

这是我想出的解决方案 http://sourceforge.net/projects/sshtools/（为清楚起见，省略了大多数错误处理）。这是my blog的摘录

SshClient ssh = new SshClient();
ssh.connect(host, port);
//Authenticate
PasswordAuthenticationClient passwordAuthenticationClient = new PasswordAuthenticationClient();
passwordAuthenticationClient.setUsername(userName);
passwordAuthenticationClient.setPassword(password);
int result = ssh.authenticate(passwordAuthenticationClient);
if(result != AuthenticationProtocolState.COMPLETE){
     throw new SFTPException("Login to " + host + ":" + port + " " + userName + "/" + password + " failed");
}
//Open the SFTP channel
SftpClient client = ssh.openSftpClient();
//Send the file
client.put(filePath);
//disconnect
client.quit();
ssh.disconnect();

Answer 6

对 3 个成熟的 SFTP Java 库进行了很好的比较：Commons VFS, SSHJ and JSch

综上所述，SSHJ 拥有最清晰的 API，如果您不需要 Commons VFS 提供的其他存储支持，它是其中最好的。

这是来自github的编辑SSHJ示例：

final SSHClient ssh = new SSHClient();
ssh.loadKnownHosts(); // or, to skip host verification: ssh.addHostKeyVerifier(new PromiscuousVerifier())
ssh.connect("localhost");
try {
    ssh.authPassword("user", "password"); // or ssh.authPublickey(System.getProperty("user.name"))
    final SFTPClient sftp = ssh.newSFTPClient();
    try {
        sftp.get("test_file", "/tmp/test.tmp");
    } finally {
        sftp.close();
    }
} finally {
    ssh.disconnect();
}

Answer 7

Apache Commons SFTP 库

所有示例的通用 java 属性文件

serverAddress=111.222.333.444

userId=myUserId

密码=我的密码

remoteDirectory=products/

localDirectory=import/

使用 SFTP 将文件上传到远程服务器

import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;

import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemOptions;
import org.apache.commons.vfs2.Selectors;
import org.apache.commons.vfs2.impl.StandardFileSystemManager;
import org.apache.commons.vfs2.provider.sftp.SftpFileSystemConfigBuilder;

public class SendMyFiles {

 static Properties props;

 public static void main(String[] args) {

  SendMyFiles sendMyFiles = new SendMyFiles();
  if (args.length < 1)
  {
   System.err.println("Usage: java " + sendMyFiles.getClass().getName()+
     " Properties_file File_To_FTP ");
   System.exit(1);
  }

  String propertiesFile = args[0].trim();
  String fileToFTP = args[1].trim();
  sendMyFiles.startFTP(propertiesFile, fileToFTP);

 }

 public boolean startFTP(String propertiesFilename, String fileToFTP){

  props = new Properties();
  StandardFileSystemManager manager = new StandardFileSystemManager();

  try {

   props.load(new FileInputStream("properties/" + propertiesFilename));
   String serverAddress = props.getProperty("serverAddress").trim();
   String userId = props.getProperty("userId").trim();
   String password = props.getProperty("password").trim();
   String remoteDirectory = props.getProperty("remoteDirectory").trim();
   String localDirectory = props.getProperty("localDirectory").trim();

   //check if the file exists
   String filepath = localDirectory +  fileToFTP;
   File file = new File(filepath);
   if (!file.exists())
    throw new RuntimeException("Error. Local file not found");

   //Initializes the file manager
   manager.init();

   //Setup our SFTP configuration
   FileSystemOptions opts = new FileSystemOptions();
   SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(
     opts, "no");
   SftpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(opts, true);
   SftpFileSystemConfigBuilder.getInstance().setTimeout(opts, 10000);

   //Create the SFTP URI using the host name, userid, password,  remote path and file name
   String sftpUri = "sftp://" + userId + ":" + password +  "@" + serverAddress + "/" + 
     remoteDirectory + fileToFTP;

   // Create local file object
   FileObject localFile = manager.resolveFile(file.getAbsolutePath());

   // Create remote file object
   FileObject remoteFile = manager.resolveFile(sftpUri, opts);

   // Copy local file to sftp server
   remoteFile.copyFrom(localFile, Selectors.SELECT_SELF);
   System.out.println("File upload successful");

  }
  catch (Exception ex) {
   ex.printStackTrace();
   return false;
  }
  finally {
   manager.close();
  }

  return true;
 }


}

使用 SFTP 从远程服务器下载文件

import java.io.File;
import java.io.FileInputStream;
import java.util.Properties;

import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemOptions;
import org.apache.commons.vfs2.Selectors;
import org.apache.commons.vfs2.impl.StandardFileSystemManager;
import org.apache.commons.vfs2.provider.sftp.SftpFileSystemConfigBuilder;

public class GetMyFiles {

 static Properties props;

 public static void main(String[] args) {

  GetMyFiles getMyFiles = new GetMyFiles();
  if (args.length < 1)
  {
   System.err.println("Usage: java " + getMyFiles.getClass().getName()+
   " Properties_filename File_To_Download ");
   System.exit(1);
  }

  String propertiesFilename = args[0].trim();
  String fileToDownload = args[1].trim();
  getMyFiles.startFTP(propertiesFilename, fileToDownload);

 }

 public boolean startFTP(String propertiesFilename, String fileToDownload){

  props = new Properties();
  StandardFileSystemManager manager = new StandardFileSystemManager();

  try {

   props.load(new FileInputStream("properties/" + propertiesFilename));
   String serverAddress = props.getProperty("serverAddress").trim();
   String userId = props.getProperty("userId").trim();
   String password = props.getProperty("password").trim();
   String remoteDirectory = props.getProperty("remoteDirectory").trim();
   String localDirectory = props.getProperty("localDirectory").trim();


   //Initializes the file manager
   manager.init();

   //Setup our SFTP configuration
   FileSystemOptions opts = new FileSystemOptions();
   SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(
     opts, "no");
   SftpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(opts, true);
   SftpFileSystemConfigBuilder.getInstance().setTimeout(opts, 10000);

   //Create the SFTP URI using the host name, userid, password,  remote path and file name
   String sftpUri = "sftp://" + userId + ":" + password +  "@" + serverAddress + "/" + 
     remoteDirectory + fileToDownload;

   // Create local file object
   String filepath = localDirectory +  fileToDownload;
   File file = new File(filepath);
   FileObject localFile = manager.resolveFile(file.getAbsolutePath());

   // Create remote file object
   FileObject remoteFile = manager.resolveFile(sftpUri, opts);

   // Copy local file to sftp server
   localFile.copyFrom(remoteFile, Selectors.SELECT_SELF);
   System.out.println("File download successful");

  }
  catch (Exception ex) {
   ex.printStackTrace();
   return false;
  }
  finally {
   manager.close();
  }

  return true;
 }

}

使用 SFTP 删除远程服务器上的文件

import java.io.FileInputStream;
import java.util.Properties;

import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemOptions;
import org.apache.commons.vfs2.impl.StandardFileSystemManager;
import org.apache.commons.vfs2.provider.sftp.SftpFileSystemConfigBuilder;

public class DeleteRemoteFile {

 static Properties props;

 public static void main(String[] args) {

  DeleteRemoteFile getMyFiles = new DeleteRemoteFile();
  if (args.length < 1)
  {
   System.err.println("Usage: java " + getMyFiles.getClass().getName()+
   " Properties_filename File_To_Delete ");
   System.exit(1);
  }

  String propertiesFilename = args[0].trim();
  String fileToDownload = args[1].trim();
  getMyFiles.startFTP(propertiesFilename, fileToDownload);

 }

 public boolean startFTP(String propertiesFilename, String fileToDownload){

  props = new Properties();
  StandardFileSystemManager manager = new StandardFileSystemManager();

  try {

   props.load(new FileInputStream("properties/" + propertiesFilename));
   String serverAddress = props.getProperty("serverAddress").trim();
   String userId = props.getProperty("userId").trim();
   String password = props.getProperty("password").trim();
   String remoteDirectory = props.getProperty("remoteDirectory").trim();


   //Initializes the file manager
   manager.init();

   //Setup our SFTP configuration
   FileSystemOptions opts = new FileSystemOptions();
   SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(
     opts, "no");
   SftpFileSystemConfigBuilder.getInstance().setUserDirIsRoot(opts, true);
   SftpFileSystemConfigBuilder.getInstance().setTimeout(opts, 10000);

   //Create the SFTP URI using the host name, userid, password,  remote path and file name
   String sftpUri = "sftp://" + userId + ":" + password +  "@" + serverAddress + "/" + 
     remoteDirectory + fileToDownload;

   //Create remote file object
   FileObject remoteFile = manager.resolveFile(sftpUri, opts);

   //Check if the file exists
   if(remoteFile.exists()){
    remoteFile.delete();
    System.out.println("File delete successful");
   }

  }
  catch (Exception ex) {
   ex.printStackTrace();
   return false;
  }
  finally {
   manager.close();
  }

  return true;
 }

}

Answer 8

hierynomus/sshj 有完整的 SFTP 版本 3 实现（OpenSSH 实现的）

来自SFTPUpload.java的示例代码

package net.schmizz.sshj.examples;

import net.schmizz.sshj.SSHClient;
import net.schmizz.sshj.sftp.SFTPClient;
import net.schmizz.sshj.xfer.FileSystemFile;

import java.io.File;
import java.io.IOException;

/** This example demonstrates uploading of a file over SFTP to the SSH server. */
public class SFTPUpload {

    public static void main(String[] args)
            throws IOException {
        final SSHClient ssh = new SSHClient();
        ssh.loadKnownHosts();
        ssh.connect("localhost");
        try {
            ssh.authPublickey(System.getProperty("user.name"));
            final String src = System.getProperty("user.home") + File.separator + "test_file";
            final SFTPClient sftp = ssh.newSFTPClient();
            try {
                sftp.put(new FileSystemFile(src), "/tmp");
            } finally {
                sftp.close();
            }
        } finally {
            ssh.disconnect();
        }
    }

}

Answer 9

JSch 库是功能强大的库，可用于从 SFTP 服务器读取文件。下面是从 SFTP 位置逐行读取文件的测试代码

JSch jsch = new JSch();
        Session session = null;
        try {
            session = jsch.getSession("user", "127.0.0.1", 22);
            session.setConfig("StrictHostKeyChecking", "no");
            session.setPassword("password");
            session.connect();

            Channel channel = session.openChannel("sftp");
            channel.connect();
            ChannelSftp sftpChannel = (ChannelSftp) channel;

            InputStream stream = sftpChannel.get("/usr/home/testfile.txt");
            try {
                BufferedReader br = new BufferedReader(new InputStreamReader(stream));
                String line;
                while ((line = br.readLine()) != null) {
                    System.out.println(line);
                }

            } catch (IOException io) {
                System.out.println("Exception occurred during reading file from SFTP server due to " + io.getMessage());
                io.getMessage();

            } catch (Exception e) {
                System.out.println("Exception occurred during reading file from SFTP server due to " + e.getMessage());
                e.getMessage();

            }

            sftpChannel.exit();
            session.disconnect();
        } catch (JSchException e) {
            e.printStackTrace();
        } catch (SftpException e) {
            e.printStackTrace();
        }

整个程序请参考blog。

Answer 10

Andy，要删除远程系统上的文件，你需要使用 JSch 的(channelExec) 并通过 unix/linux 命令来删除它。

Answer 11

试试edtFTPj/PRO，这是一个成熟、强大的 SFTP 客户端库，支持连接池和异步操作。还支持 FTP 和 FTPS，因此涵盖了安全文件传输的所有基础。

Answer 12

我使用 JSCH API 在 java 中找到了 SFTP 的完整工作示例 http://kodehelp.com/java-program-for-uploading-file-to-sftp-server/

Answer 13

虽然上面的答案非常有帮助，但我还是花了一天时间让它们正常工作，但遇到了各种异常，例如“损坏的通道”、“未知的 rsa 密钥”和“数据包损坏”。

下面是一个使用 JSch 库的 SFTP 文件上传/下载的可重用类。

上传使用情况：

SFTPFileCopy upload = new SFTPFileCopy(true, /path/to/sourcefile.png", /path/to/destinationfile.png");

下载使用：

SFTPFileCopy download = new SFTPFileCopy(false, "/path/to/sourcefile.png", "/path/to/destinationfile.png");

类代码：

import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.UIKeyboardInteractive;
import com.jcraft.jsch.UserInfo;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.swing.JOptionPane;
import menue.Menue;

public class SFTPFileCopy1 {

    public SFTPFileCopy1(boolean upload, String sourcePath, String destPath) throws FileNotFoundException, IOException {
        Session session = null;
        Channel channel = null;
        ChannelSftp sftpChannel = null;
        try {
            JSch jsch = new JSch();
            //jsch.setKnownHosts("/home/user/.putty/sshhostkeys");
            session = jsch.getSession("login", "mysite.com", 22);
            session.setPassword("password");

            UserInfo ui = new MyUserInfo() {
                public void showMessage(String message) {

                    JOptionPane.showMessageDialog(null, message);

                }

                public boolean promptYesNo(String message) {

                    Object[] options = {"yes", "no"};

                    int foo = JOptionPane.showOptionDialog(null,
                            message,
                            "Warning",
                            JOptionPane.DEFAULT_OPTION,
                            JOptionPane.WARNING_MESSAGE,
                            null, options, options[0]);

                    return foo == 0;

                }
            };
            session.setUserInfo(ui);

            session.setConfig("StrictHostKeyChecking", "no");
            session.connect();
            channel = session.openChannel("sftp");
            channel.setInputStream(System.in);
            channel.setOutputStream(System.out);
            channel.connect();
            sftpChannel = (ChannelSftp) channel;

            if (upload) { // File upload.
                byte[] bufr = new byte[(int) new File(sourcePath).length()];
                FileInputStream fis = new FileInputStream(new File(sourcePath));
                fis.read(bufr);
                ByteArrayInputStream fileStream = new ByteArrayInputStream(bufr);
                sftpChannel.put(fileStream, destPath);
                fileStream.close();
            } else { // File download.
                byte[] buffer = new byte[1024];
                BufferedInputStream bis = new BufferedInputStream(sftpChannel.get(sourcePath));
                OutputStream os = new FileOutputStream(new File(destPath));
                BufferedOutputStream bos = new BufferedOutputStream(os);
                int readCount;
                while ((readCount = bis.read(buffer)) > 0) {
                    bos.write(buffer, 0, readCount);
                }
                bis.close();
                bos.close();
            }
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            if (sftpChannel != null) {
                sftpChannel.exit();
            }
            if (channel != null) {
                channel.disconnect();
            }
            if (session != null) {
                session.disconnect();
            }
        }
    }

    public static abstract class MyUserInfo
            implements UserInfo, UIKeyboardInteractive {

        public String getPassword() {
            return null;
        }

        public boolean promptYesNo(String str) {
            return false;
        }

        public String getPassphrase() {
            return null;
        }

        public boolean promptPassphrase(String message) {
            return false;
        }

        public boolean promptPassword(String message) {
            return false;
        }

        public void showMessage(String message) {
        }

        public String[] promptKeyboardInteractive(String destination,
                String name,
                String instruction,
                String[] prompt,
                boolean[] echo) {

            return null;
        }
    }
}

Answer 14

您还拥有带有 SFTP 附加组件的 JFileUpload（Java 也是）： http://www.jfileupload.com/products/sftp/index.html

Answer 15

我使用这个名为 Zehon 的 SFTP API，它非常棒，使用大量示例代码非常容易使用。这里是网站http://www.zehon.com

Answer 16

我找到的最佳解决方案是Paramiko。有 Java 版本。