使用 JSch 在 SSH 上运行命令

以下用 Java 编写的代码示例将允许您从 Java 程序中通过 SSH 在外部计算机上执行任何命令。您需要包含 com.jcraft.jsch jar 文件。

  /* 
  * SSHManager
  * 
  * @author cabbott
  * @version 1.0
  */
  package cabbott.net;

  import com.jcraft.jsch.*;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.logging.Level;
  import java.util.logging.Logger;

  public class SSHManager
  {
  private static final Logger LOGGER = 
      Logger.getLogger(SSHManager.class.getName());
  private JSch jschSSHChannel;
  private String strUserName;
  private String strConnectionIP;
  private int intConnectionPort;
  private String strPassword;
  private Session sesConnection;
  private int intTimeOut;

  private void doCommonConstructorActions(String userName, 
       String password, String connectionIP, String knownHostsFileName)
  {
     jschSSHChannel = new JSch();

     try
     {
        jschSSHChannel.setKnownHosts(knownHostsFileName);
     }
     catch(JSchException jschX)
     {
        logError(jschX.getMessage());
     }

     strUserName = userName;
     strPassword = password;
     strConnectionIP = connectionIP;
  }

  public SSHManager(String userName, String password, 
     String connectionIP, String knownHostsFileName)
  {
     doCommonConstructorActions(userName, password, 
                connectionIP, knownHostsFileName);
     intConnectionPort = 22;
     intTimeOut = 60000;
  }

  public SSHManager(String userName, String password, String connectionIP, 
     String knownHostsFileName, int connectionPort)
  {
     doCommonConstructorActions(userName, password, connectionIP, 
        knownHostsFileName);
     intConnectionPort = connectionPort;
     intTimeOut = 60000;
  }

  public SSHManager(String userName, String password, String connectionIP, 
      String knownHostsFileName, int connectionPort, int timeOutMilliseconds)
  {
     doCommonConstructorActions(userName, password, connectionIP, 
         knownHostsFileName);
     intConnectionPort = connectionPort;
     intTimeOut = timeOutMilliseconds;
  }

  public String connect()
  {
     String errorMessage = null;

     try
     {
        sesConnection = jschSSHChannel.getSession(strUserName, 
            strConnectionIP, intConnectionPort);
        sesConnection.setPassword(strPassword);
        // UNCOMMENT THIS FOR TESTING PURPOSES, BUT DO NOT USE IN PRODUCTION
        // sesConnection.setConfig("StrictHostKeyChecking", "no");
        sesConnection.connect(intTimeOut);
     }
     catch(JSchException jschX)
     {
        errorMessage = jschX.getMessage();
     }

     return errorMessage;
  }

  private String logError(String errorMessage)
  {
     if(errorMessage != null)
     {
        LOGGER.log(Level.SEVERE, "{0}:{1} - {2}", 
            new Object[]{strConnectionIP, intConnectionPort, errorMessage});
     }

     return errorMessage;
  }

  private String logWarning(String warnMessage)
  {
     if(warnMessage != null)
     {
        LOGGER.log(Level.WARNING, "{0}:{1} - {2}", 
           new Object[]{strConnectionIP, intConnectionPort, warnMessage});
     }

     return warnMessage;
  }

  public String sendCommand(String command)
  {
     StringBuilder outputBuffer = new StringBuilder();

     try
     {
        Channel channel = sesConnection.openChannel("exec");
        ((ChannelExec)channel).setCommand(command);
        InputStream commandOutput = channel.getInputStream();
        channel.connect();
        int readByte = commandOutput.read();

        while(readByte != 0xffffffff)
        {
           outputBuffer.append((char)readByte);
           readByte = commandOutput.read();
        }

        channel.disconnect();
     }
     catch(IOException ioX)
     {
        logWarning(ioX.getMessage());
        return null;
     }
     catch(JSchException jschX)
     {
        logWarning(jschX.getMessage());
        return null;
     }

     return outputBuffer.toString();
  }

  public void close()
  {
     sesConnection.disconnect();
  }

  }

用于测试。

  /**
     * Test of sendCommand method, of class SSHManager.
     */
  @Test
  public void testSendCommand()
  {
     System.out.println("sendCommand");

     /**
      * YOU MUST CHANGE THE FOLLOWING
      * FILE_NAME: A FILE IN THE DIRECTORY
      * USER: LOGIN USER NAME
      * PASSWORD: PASSWORD FOR THAT USER
      * HOST: IP ADDRESS OF THE SSH SERVER
     **/
     String command = "ls FILE_NAME";
     String userName = "USER";
     String password = "PASSWORD";
     String connectionIP = "HOST";
     SSHManager instance = new SSHManager(userName, password, connectionIP, "");
     String errorMessage = instance.connect();

     if(errorMessage != null)
     {
        System.out.println(errorMessage);
        fail();
     }

     String expResult = "FILE_NAME\n";
     // call sendCommand for each command and the output 
     //(without prompts) is returned
     String result = instance.sendCommand(command);
     // close only after all commands are sent
     instance.close();
     assertEquals(expResult, result);
  }

这是一个无耻的插件，但我现在刚刚为JSch编写了一些广泛的Javadoc。

此外，现在JSch Wiki中有一个手册（主要由我编写）。

关于原始问题，没有真正处理流的示例。读取/写入流是一如既往的。

但是，根本无法确定如何通过读取 shell 的输出来了解 shell 中的一个命令何时完成（这与 SSH 协议无关）。

如果shell是交互式的，即它附加了一个终端，它通常会打印一个提示，你可以尝试识别。但至少从理论上讲，这个提示字符串也可能出现在命令的正常输出中。如果要确定，请为每个命令打开单独的通道，而不是使用 shell 通道。我认为，shell通道主要用于人类用户的交互式使用。exec