【Jsch】使用SSH协议连接到远程Shell执行脚本

如果大家熟悉Linux的话，一定对ssh,sftp,scp等命令非常熟悉，ssh是一个安全协议，用来在不同系统或者服务器之间进行安全连接，SSH 在连接和传送的过程中会加密所有的数据。

但是SSH一般是基于客户端的或者Linux命令行的，比如客户端的工具:OpenSSH,putty,SSH Tectia；

在linux上大家可以通过ssh username@host连接到所要想连接的主机。

但是如果在J2EE中，如何实现SSH呢？进而可以实现SCP,SFTP的功能呢？下面介绍的JSCH就可以实现下边的功能。

JSCH是一个纯粹的用java实现SSH功能的java  library;

JSCH API：http://epaul.github.io/jsch-documentation/javadoc/   

Example： http://www.jcraft.com/jsch/examples/ 

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maven依赖

<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>
    <version>0.1.44</version>
</dependency>

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关键类介绍

• JSch:  作为中心配置点，以及Session的工厂；

 This class serves as a central configuration point, and as a factory for Session objects configured with these settings.

1. Use getSession to start a new Session.
   
2. Use one of the addIdentity methods for public-key authentication.
   
3. Use setKnownHosts to enable checking of host keys.
   
4. See setConfig for a list of configuration options.
   

• Session：表示到远程SSH服务器的一个连接，可以包含多个Channels；

 A Session represents a connection to a SSH server.One session can contain multiple Channels of various types

A session is opened with connect() and closed with disconnect().

• Channel :  与Session相关联的通道，有多种不同类型；

The abstract base class for the different types of channel which may be associated with a Session.

1. shell - ChannelShell ：A channel connected to a remote shell (本次使用的Channel)
   
2. exec - ChannelExec ：A channel connected to a remotely executing program
   
3. direct-tcpip - ChannelDirectTCPIP： A Channel which allows forwarding a pair of local streams to/from a TCP-connection to a server on the remote side
   
4. sftp - ChannelSftp ：A Channel connected to an sftp server (as a subsystem of the ssh server).
   
5. subsystem - ChannelSubsystem ：A channel connected to a subsystem of the server process
   

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使用步骤

使用Jsch进行SSH连接的具体步骤如下:

• 步骤1： 使用Jsch获取Session: jsch.getSession()
  
• 步骤2： 设置Session的password和属性等: setPassword()/setConfig();
  
• 步骤3： 设置SocketFactory（可以不进行设置,使用默认的TCP socket）;
  
• 步骤4： 打开Session连接：connect();
  
• 步骤5： 打开并连接Channel：openChannel()/connect();
  
• 步骤6： 获取Channel的inputStream和outputStream，执行指定cmd或其他；
  

1.   getInputStream():  All data arriving in SSH_MSG_CHANNEL_DATA messages from the remote side can be read from this stream
   
2.   getOutputStream():  All data written to this stream will be sent in SSH_MSG_CHANNEL_DATA messages to the remote side.
   

• 步骤7： 关闭各种资源：输入输出流/Session/Channel等；
  

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创建Session，并打开Session连接

步骤1~步骤4：程序如下

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使用SSH协议，连接到Linux，执行指定命令，并获取结果

步骤5~步骤6：程序如下

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执行Shell命令，并获取执行结果

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测试程序

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完整程序

JSCHUtil.java

package com.sssppp.Communication;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Properties;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SocketFactory;
/**
 * 相关链接： JSCH api：http://epaul.github.io/jsch-documentation/javadoc/ Example:
 * http://www.jcraft.com/jsch/examples/
 * 
 * @author xxxx
 * 
 */
public class JSCHUtil {
  private static JSch jsch = new JSch();
  /**
   * 创建Session，并打开Session连接
   * 
   * @param dstIp
   * @param dstPort
   * @param localIp
   * @param localPort
   * @param userName
   * @param password
   * @param timeOut
   * @return
   * @throws JSchException
   */
  public static Session createSession(String dstIp, int dstPort,
      final String localIp, final int localPort, String userName,
      String password, final int timeOut) throws JSchException {
    //jsch.setKnownHosts("/home/foo/.ssh/known_hosts");
    
    // A Session represents a connection to a SSH server
    Session session = jsch.getSession(userName, dstIp, dstPort);
    session.setPassword(password);
    
    Properties sshConfig = new Properties();
    sshConfig.put("StrictHostKeyChecking", "no");//To skip host-key check
    session.setConfig(sshConfig);
    // this socket factory is used to create a socket to the target host,
    // and also create the streams of this socket used by us
    session.setSocketFactory(new SocketFactory() {
      @Override
      public OutputStream getOutputStream(Socket socket)
          throws IOException {
        return socket.getOutputStream();
      }
      @Override
      public InputStream getInputStream(Socket socket) throws IOException {
        return socket.getInputStream();
      }
      @Override
      public Socket createSocket(String host, int port)
          throws IOException, UnknownHostException {
        Socket socket = new Socket();
        if (localIp != null) {
          socket.bind(new InetSocketAddress(InetAddress
              .getByName(localIp), localPort));
        }
        socket.connect(
            new InetSocketAddress(InetAddress.getByName(host), port),
            timeOut);
        return socket;
      }
    });
    session.connect(timeOut);
    return session;
  }
}

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SSHCommUtil.java

package com.sssppp.Communication;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import com.jcraft.jsch.Channel;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
public class SSHCommUtil {
  /**
   * 测试程序
   * @param args
   */
  public static void main(String[] args) {
    String ip = "10.180.137.241";
    int port = 22;
    String localIp = null;
    int localPort = 0;
    int timeOut = 3000;
    String userName = "xxx";
    String password = "xxx";
    String[] cmds = new String[] { "ifconfig | grep eth0\n",
        "cat /etc/redhat-release\n" };
    String[] result = null;
    try {
      result = execShellCmdBySSH(ip, port, localIp, localPort, timeOut,
          userName, password, cmds);
    } catch (Exception e) {
      e.printStackTrace();
    }
    if (result != null) {
      for (String string : result) {
        System.out.println(string);
        System.out.println("-------------------");
      }
    }
  }
  /**
   * 使用SSH协议，连接到Linux Shell，执行脚本命令，并获取结果
   * 
   * @param dstIp
   * @param dstport
   *            default :22
   * @param localIp
   * @param localPort
   * @param timeOut
   * @param userName
   * @param password
   * @param cmds
   * @return
   * @throws Exception
   */
  public static String[] execShellCmdBySSH(String dstIp, int dstport,
      String localIp, int localPort, int timeOut, String userName,
      String password, String... cmds) throws Exception {
    Session session = null;
    Channel channel = null;
    InputStream is = null;
    OutputStream os = null;
    try {
      session = JSCHUtil.createSession(dstIp, dstport, localIp,
          localPort, userName, password, timeOut);
      channel = session.openChannel("shell");
    
      // Enable agent-forwarding.
      // ((ChannelShell)channel).setAgentForwarding(true);
      // Choose the pty-type "vt102".
      // ((ChannelShell)channel).setPtyType("vt102");
      // Set environment variable "LANG" as "ja_JP.eucJP".
      // ((ChannelShell)channel).setEnv("LANG", "ja_JP.eucJP");
      channel.connect();
      is = channel.getInputStream();
      os = channel.getOutputStream();
      String[] result = new String[cmds.length];
      for (int i = 0; i < cmds.length; i++) {
        result[i] = sendCommand(is, os, cmds[i]);
      }
      return result;
    } catch (JSchException e) {
      if (e.getMessage().contains("Auth fail")) {
        throw new Exception("Auth error");
      } else {
        throw new Exception("Connect error");
      }
    } catch (Exception e) {
      throw e;
    } finally {
      try {
        is.close();
      } catch (IOException e) {
      }
      try {
        os.close();
      } catch (IOException e) {
      }
      channel.disconnect();
      session.disconnect();
    }
  }
  
  /**
   * 执行Shell命令，并获取执行结果
   * 
   * @param is
   * @param os
   * @param cmd
   * @return
   * @throws IOException
   */
  private static String sendCommand(InputStream is, OutputStream os,
      String cmd) throws IOException {
    os.write(cmd.getBytes());
    os.flush();
    StringBuffer sb = new StringBuffer();
    int beat = 0;
    while (true) {
      if (beat > 3) {
        break;
      }
      if (is.available() > 0) {
        byte[] b = new byte[is.available()];
        is.read(b);
        sb.append(new String(b));
        beat = 0;
      } else {
        if (sb.length() > 0) {
          beat++;
        }
        try {
          Thread.sleep(sb.toString().trim().length() == 0 ? 1000
              : 300);
        } catch (InterruptedException e) {
        }
      }
    }
    return sb.toString();
  }
}

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来自为知笔记(Wiz)