急急急！！用java代码远程调用linux命令为啥不出来结果啊！！！命令：java -version...



代码如下：

public class ConnectUtil {

public static String cmdExcute(String value) {
String result = "";
try {
Connection conn = getConnection();
Session ssh = getSession(conn);
ssh.execCommand(value);
InputStream is = new StreamGobbler(ssh.getStdout());
BufferedReader brs = new BufferedReader(new InputStreamReader(is));
StringBuffer sb = new StringBuffer();
while (true) {
String line = brs.readLine();
if (line == null) {
break;
}
sb.append(line);

}
result = sb.toString();
closeConnection(conn, ssh);

} catch (IOException e) {
e.printStackTrace();
}
return result;
}

public static void main(String[] args){

System.out.println(ConnectUtil.cmdExcute("java -version"));

}

}