ganymed-ssh2 执行命令(execCommand)环境变量缺失

傷城~ 2022-04-21 15:14 125阅读 0赞

### 详细如下： ###

pom：

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

在java程序中使用ganymed-ssh2，采用exec的session方式   
使用exec的方式登录不能获得当前用户的环境变量。比如会报 bash: java: command not found   
解决办法:   
String JAVA\_HOME="export JAVA\_HOME=/usr/java/jdk1.8.0\_77";   
ssh.execCommand(JAVA\_HOME+";"+otherCommand)   
另外还有一种办法就是PTY，建立输入流直接向终端输入命令详见

代码我参考了前辈的：如下：

最常见是当执行session.execcommand()这个命令的时候，出现在远程机器上环境变量丢失或者错误的问题。

因此不用session.execCommand()，用获取pty(虚拟终端)和启动sell命令来代替，(use Session.requestPTY() and Session.startShell())。这样你就不得不在另一方面通过用stdin和stdout来和shell进程通信。不管怎么样，当你要实现终端的算法时，例如（e.g.escape sequence handling (unless you use a "dumb" pty)，"expect-send" logic (output parsing, shell prompt detection), etc.)

package c1;  
import ch.ethz.ssh2.ChannelCondition;  
import ch.ethz.ssh2.Connection;  
import ch.ethz.ssh2.Session;  
import ch.ethz.ssh2.StreamGobbler;

import java.io.BufferedReader;

import java.io.IOException;  
import java.io.InputStream;  
import java.io.InputStreamReader;

import java.io.PrintWriter;

public class Test4 \{

public static void main(String args\[\]) \{  
     try  
  \{  
   /\* Create a connection instance \*/  
   Connection conn = new Connection("127.0.0.1");  
     
   /\* Now connect \*/  
   conn.connect();  
   /\* Authenticate \*/  
   boolean isAuthenticated = conn.authenticateWithPassword("username","password");  
   if (isAuthenticated == false)  
    throw new IOException("Authentication failed. Please check hostname, username and password.");  
   /\* Create a session \*/  
   Session sess = conn.openSession();  
   // sess.execCommand("uname -a && date && uptime && who");  
   System.out.println("start exec command.......");

//sess.execCommand("echo /"Text on STDOUT/"; echo /"Text on STDERR/" >&2");  
   //sess.execCommand("env");  
            sess.requestPTY("bash");  
              
            sess.startShell();  
              
              
   InputStream stdout = new StreamGobbler(sess.getStdout());  
   InputStream stderr = new StreamGobbler(sess.getStderr());  
   
   BufferedReader stdoutReader = new BufferedReader(new InputStreamReader(stdout));  
   BufferedReader stderrReader = new BufferedReader(new InputStreamReader(stderr));

//if you want to use sess.getStdin().write(), here is a sample  
   //byte b\[\]=\{'e','n','v','/n'\};  
   //byte b\[\]=\{'e','x','i','t','/n'\};  
   //sess.getStdin().write(b)

/\*

String str="env";  
   String str1="exit";  
   System.out.println(str+str1);  
   out.write(str.getBytes());  
   out.write('/n');  
   out.write(str1.getBytes());  
   out.write('/n');

\*/  
   //we used PrintWriter, it makes things simple  
   PrintWriter out =new PrintWriter(sess.getStdin());

out.println("env");  
   out.println("exit");

out.close();  
   sess.waitForCondition(ChannelCondition.CLOSED | ChannelCondition.EOF | ChannelCondition.EXIT\_STATUS, 30000);  
     
   System.out.println("Here is the output from stdout:");  
     
   while (true)  
   \{  
    String line = stdoutReader.readLine();  
    if (line == null)  
     break;  
    System.out.println(line);  
   \}  
   System.out.println("Here is the output from stderr:");  
   while (true)  
   \{  
    String line = stderrReader.readLine();  
    if (line == null)  
     break;  
    System.out.println(line);  
   \}  
   /\* Show exit status, if available (otherwise "null") \*/  
   System.out.println("ExitCode: " + sess.getExitStatus());  
   sess.close();/\* Close this session \*/     
   conn.close();/\* Close the connection \*/  
   
  \}  
  catch (IOException e)  
  \{  
   e.printStackTrace(System.err);  
   System.exit(2);  
  \}  
  \}  
    \}

### 这里学习了前辈的博客 ###

[https://blog.csdn.net/cfhacker007/article/details/5707094][https_blog.csdn.net_cfhacker007_article_details_5707094]

尊重原作者

[https_blog.csdn.net_cfhacker007_article_details_5707094]: https://blog.csdn.net/cfhacker007/article/details/5707094