基于Java实现ssh命令登录主机执行shell命令过程解析

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.Calendar;

import org.apache.commons.lang3.StringUtils;

import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.Session;
import ch.ethz.ssh2.StreamGobbler;


public class SshUtil {
 private static String DEFAULT_CHAR_SET = "UTF-8";
 private static String tipStr = "=======================%s=======================";
 private static String splitStr = "=====================================================";
 
 /**
  * 登录主机
  * @return
  *  登录成功返回true，否则返回false
  */
 public static Connection login(String ip, String userName, String password){
  boolean isAuthenticated = false;
  Connection conn = null;
  long startTime = Calendar.getInstance().getTimeInMillis();
  try {
   conn = new Connection(ip);
   conn.connect(); // 连接主机

   isAuthenticated = conn.authenticateWithPassword(userName, password); // 认证
   if(isAuthenticated){
    System.out.println(String.format(tipStr, "认证成功"));
   } else {
    System.out.println(String.format(tipStr, "认证失败"));
   }
  } catch (IOException e) {
   System.err.println(String.format(tipStr, "登录失败"));
   e.printStackTrace();
  }
  long endTime = Calendar.getInstance().getTimeInMillis();
  System.out.println("登录用时: " + (endTime - startTime)/1000.0 + "s\n" + splitStr);
  return conn;
 }
 
 /**
  * 远程执行shell脚本或者命令
  * @param cmd
  *  即将执行的命令
  * @return
  *  命令执行完后返回的结果值
  */
 public static String execute(Connection conn, String cmd){
  String result = "";
  Session session = null;
  try {
   if(conn != null){
    session = conn.openSession(); // 打开一个会话
    session.execCommand(cmd);  // 执行命令
    result = processStdout(session.getStdout(), DEFAULT_CHAR_SET);

    //如果为得到标准输出为空，说明脚本执行出错了
    if(StringUtils.isBlank(result)){
     System.err.println("【得到标准输出为空】\n执行的命令如下：\n" + cmd);
     result = processStdout(session.getStderr(), DEFAULT_CHAR_SET);
    }else{
     System.out.println("【执行命令成功】\n执行的命令如下：\n" + cmd);
    }
   }
  } catch (IOException e) {
   System.err.println("【执行命令失败】\n执行的命令如下：\n" + cmd + "\n" + e.getMessage());
   e.printStackTrace();
  } finally {
   if (conn != null) {
    conn.close();
   }
   if (session != null) {
    session.close();
   }
  }
  return result;
 }

 /**
  * 解析脚本执行返回的结果集
  * @param in 输入流对象
  * @param charset 编码
  * @return
  *  以纯文本的格式返回
  */
 private static String processStdout(InputStream in, String charset){
  InputStream stdout = new StreamGobbler(in);
  StringBuffer buffer = new StringBuffer();
  try {
   BufferedReader br = new BufferedReader(new InputStreamReader(stdout, charset));
   String line = null;
   while((line = br.readLine()) != null){
    buffer.append(line + "\n");
   }
  } catch (UnsupportedEncodingException e) {
   System.err.println("解析脚本出错：" + e.getMessage());
   e.printStackTrace();
  } catch (IOException e) {
   System.err.println("解析脚本出错：" + e.getMessage());
   e.printStackTrace();
  }
  return buffer.toString();
 }

 public static void main(String[] args){
  String ip = "192.168.123.234"; // 此处根据实际情况，换成自己需要访问的主机IP
  String userName = "root";
  String password = "password";
  Connection conn = SshUtil.login(ip, userName, password);

  String cmd = "cd /home/miracle&&pwd&&ls&&cat luna.txt";
  String result = SshUtil.execute(conn, cmd);
  System.out.println(splitStr + "\n执行的结果如下: \n" + result + splitStr);
 }
}

=======================认证成功=======================
登录用时: 0.859s
=====================================================
【执行命令成功】
执行的命令如下：
cd /home/miracle&&pwd&&ls&&cat luna.txt
=====================================================
执行的结果如下: 
/home/miracle
luna.txt
Hello, I'm SshUtil.
Nice to meet you.^_^
=====================================================

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
  <dependency>
   <groupId>org.apache.commons</groupId>
   <artifactId>commons-lang3</artifactId>
   <version>3.9</version>
  </dependency>

  <!-- ssh -->
  <dependency>
   <groupId>ch.ethz.ganymed</groupId>
   <artifactId>ganymed-ssh2</artifactId>
   <version>262</version>
  </dependency>