使用 JSch 通过 SSH 运行命令 [英] Run a command over SSH with JSch

问题描述

我正在尝试使用 JSch 通过 SSH 运行命令，但 JSch 几乎没有文档，而且我发现的示例很糟糕.例如，这个 没有显示处理输出流的代码.而且，这个使用了一个丑陋的黑客来知道何时停止从输出流读取.

I'm trying to run a command over SSH with JSch, but JSch has virtually no documentation and the examples I've found are terrible. For example, this one doesn't show code for handling the output stream. And, this one uses an ugly hack to know when to stop reading from the output stream.

推荐答案

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
";
     // 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);
  }

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