Java SSH远程执行Shell脚本实现

此程序需要ganymed-ssh2-build210.jar包。

下载地址：http://www.ganymed.ethz.ch/ssh2/

为了调试方便，可以将\ganymed-ssh2-build210\src下的代码直接拷贝到我们的工程里，

此源码的好处就是没有依赖很多其他的包，拷贝过来干干净净。

此程序的目的是执行远程机器上的Shell脚本。

远程机器IP：***.**.**.***

用户名：sshapp

密码：sshapp

登录后用pwd命令，显示当前目录为：/sshapp.

在/sshapp/myshell/目录下有myTest.sh文件，内容如下：


echo $1 $2 $#


#print $1

我们的Java代码RmtShellExecutor.java：

/** *//**
* 远程执行shell脚本类
* @author l
*/
public class RmtShellExecutor {

/** *//**  */
private Connection conn;
/** *//** 远程机器IP */
private String     ip;
/** *//** 用户名 */
private String     usr;
/** *//** 密码 */
private String     psword;
private String     charset = Charset.defaultCharset().toString();

private static final int TIME_OUT = 1000 * 5 * 60;

/** *//**
* 构造函数
* @param param 传入参数Bean 一些属性的getter setter 实现略
*/
public RmtShellExecutor(ShellParam param) {
this.ip = param.getIp();
this.usr = param.getUsername();
this.psword = param.getPassword();
}

/** *//**
* 构造函数
* @param ip
* @param usr
* @param ps
*/
public RmtShellExecutor(String ip, String usr, String ps) {
this.ip = ip;
this.usr = usr;
this.psword = ps;
}

/** *//**
* 登录
*
* @return
* @throws IOException
*/
private boolean login() throws IOException {
conn = new Connection(ip);
conn.connect();
return conn.authenticateWithPassword(usr, psword);
}

/** *//**
* 执行脚本
*
* @param cmds
* @return
* @throws Exception
*/
public int exec(String cmds) throws Exception {
InputStream stdOut = null;
InputStream stdErr = null;
String outStr = "";
String outErr = "";
int ret = -1;
try {
if (login()) {
// Open a new {@link Session} on this connection
Session session = conn.openSession();
// Execute a command on the remote machine.
session.execCommand(cmds);

stdOut = new StreamGobbler(session.getStdout());
outStr = processStream(stdOut, charset);

stdErr = new StreamGobbler(session.getStderr());
outErr = processStream(stdErr, charset);

session.waitForCondition(ChannelCondition.EXIT_STATUS, TIME_OUT);

System.out.println("outStr=" + outStr);
System.out.println("outErr=" + outErr);

ret = session.getExitStatus();
} else {
throw new AppException("登录远程机器失败" + ip); // 自定义异常类 实现略
}
} finally {
if (conn != null) {
conn.close();
}
IOUtils.closeQuietly(stdOut);
IOUtils.closeQuietly(stdErr);
}
return ret;
}

/** *//**
* @param in
* @param charset
* @return
* @throws IOException
* @throws UnsupportedEncodingException
*/
private String processStream(InputStream in, String charset) throws Exception {
byte[] buf = new byte[1024];
StringBuilder sb = new StringBuilder();
while (in.read(buf) != -1) {
sb.append(new String(buf, charset));
}
return sb.toString();
}

public static void main(String args[]) throws Exception {
RmtShellExecutor exe = new RmtShellExecutor("***.**.**.***", "sshapp", "sshapp");
// 执行myTest.sh 参数为java Know dummy
System.out.println(exe.exec("sh /webapp/myshell/myTest.sh java Know dummy"));
//        exe.exec("uname -a && date && uptime && who");
}
}

执行后结果：


outStr=java Know 3


outErr=


0 // getExitStatus方法的返回值

注：一般情况下shell脚本正常执行完毕，getExitStatus方法返回0。

此方法通过远程命令取得Exit Code/status。但并不是每个server设计时都会返回这个值，如果没有则会返回null。

在调用getExitStatus时，要先调用WaitForCondition方法，通过ChannelCondition.java接口的定义可以看到每个条件的具体含义。见以下代码：

ChannelCondition.java

package ch.ethz.ssh2;

/** *//**
* Contains constants that can be used to specify what conditions to wait for on
* a SSH-2 channel (e.g., represented by a {@link Session}).
*
* @see Session#waitForCondition(int, long)
*
* @author Christian Plattner, plattner@inf.ethz.ch
* @version $Id: ChannelCondition.java,v 1.6 2006/08/11 12:24:00 cplattne Exp $
*/

public abstract interface ChannelCondition
{
/** *//**
* A timeout has occurred, none of your requested conditions is fulfilled.
* However, other conditions may be true - therefore, NEVER use the "=="
* operator to test for this (or any other) condition. Always use
* something like <code>((cond & ChannelCondition.CLOSED) != 0)</code>.
*/
public static final int TIMEOUT = 1;

/** *//**
* The underlying SSH-2 channel, however not necessarily the whole connection,
* has been closed. This implies <code>EOF</code>. Note that there may still
* be unread stdout or stderr data in the local window, i.e, <code>STDOUT_DATA</code>
* or/and <code>STDERR_DATA</code> may be set at the same time.
*/
public static final int CLOSED = 2;

/** *//**
* There is stdout data available that is ready to be consumed.
*/
public static final int STDOUT_DATA = 4;

/** *//**
* There is stderr data available that is ready to be consumed.
*/
public static final int STDERR_DATA = 8;

/** *//**
* EOF on has been reached, no more _new_ stdout or stderr data will arrive
* from the remote server. However, there may be unread stdout or stderr
* data, i.e, <code>STDOUT_DATA</code> or/and <code>STDERR_DATA</code>
* may be set at the same time.
*/
public static final int EOF = 16;

/** *//**
* The exit status of the remote process is available.
* Some servers never send the exist status, or occasionally "forget" to do so.
*/
public static final int EXIT_STATUS = 32;

/** *//**
* The exit signal of the remote process is available.
*/
public static final int EXIT_SIGNAL = 64;

}

当我们把myTest.sh修改为如下内容：


echo $1 $2 $#


print $1

由于我使用的linux机器上没有print命令，所以print $1会报错：command not found。

接下来再让我们执行一下，看看控制台的结果：


outStr=java Know 3


outErr=/sshapp/myshell/myTest.sh: line 2: print: command not found


127



此时shell脚本出现错误，getExitStatus方法返回127.

在实际应用中，可以将outStr和outErr记录到日志中，以便维护人员查看shell的执行情况，

而getExitStatus的返回值，可以认为是此次执行是否OK的标准。