如何通过 Java 在 SSH 中运行多个命令？

Question

如何使用 Java 运行时在 SSH 中运行多个命令？

命令： ssh user@127.0.0.1 'export MYVAR=this/dir/is/cool; /运行/我的/脚本 /我的脚本；回声 $MYVAR'

@Test
  public void testSSHcmd() throws Exception
  {
    StringBuilder cmd = new StringBuilder();

    cmd.append("ssh ");
    cmd.append("user@127.0.0.1 ");
    cmd.append("'export ");
    cmd.append("MYVAR=this/dir/is/cool; ");
    cmd.append("/run/my/script/myScript; ");
    cmd.append("echo $MYVAR'");

    Process p = Runtime.getRuntime().exec(cmd.toString());
  }

该命令本身会起作用，但当尝试从 java 运行时执行时却不起作用。有什么建议或建议吗？

Answer 1

使用较新的 ProcessBuilder 类而不是 Runtime.exec。您可以通过指定程序及其参数列表来构造一个，如下面的代码所示。您不需要在命令周围使用单引号。您还应该阅读 stdout 和 stderr 流以及 waitFor 以完成该过程。

ProcessBuilder pb = new ProcessBuilder("ssh", 
                                       "user@127.0.0.1", 
                                       "export MYVAR=this/dir/is/cool; /run/my/script/myScript; echo $MYVAR");
pb.redirectErrorStream(); //redirect stderr to stdout
Process process = pb.start();
InputStream inputStream = process.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
String line = null;
while((line = reader.readLine())!= null) {
    System.out.println(line);
}
process.waitFor();

Answer 2

如果Process 只是挂起，我怀疑/run/my/script/myScript 会向stderr 输出一些东西。您需要处理该输出以及stdout：

public static void main(String[] args) throws Exception {
    String[] cmd = {"ssh", "root@localhost", "'ls asd; ls'" };
    final Process p = Runtime.getRuntime().exec(cmd);

    // ignore all errors (print to std err)
    new Thread() {
        @Override
        public void run() {
            try {
                BufferedReader err = new BufferedReader(
                        new InputStreamReader(p.getErrorStream()));
                String in;
                while((in = err.readLine()) != null)
                    System.err.println(in);
                err.close();
            } catch (IOException e) {}
        }
    }.start();

    // handle std out
    InputStreamReader isr = new InputStreamReader(p.getInputStream());
    BufferedReader reader = new BufferedReader(isr);

    StringBuilder ret = new StringBuilder();
    char[] data = new char[1024];
    int read;
    while ((read = reader.read(data)) != -1)
        ret.append(data, 0, read);
    reader.close();

    // wait for the exit code
    int exitCode = p.waitFor();
}

Answer 3

您正在调用的Runtime.exec 的veriant 将命令字符串拆分为几个标记，然后将这些标记传递给ssh。您需要的是可以提供字符串数组的变体之一。将完整的远程部分放入一个参数中，同时去除外部引号。示例

Runtime.exec(new String[]{ 
    "ssh", 
    "user@127.0.0.1", 
    "export MYVAR=this/dir/is/cool; /run/my/script/myScript; echo $MYVAR"
});

就是这样。

Answer 4

您可能想看看JSch 库。它允许您对远程主机执行各种 SSH 操作，包括执行命令和脚本。

他们在此处列出了示例：http://www.jcraft.com/jsch/examples/

Answer 5

这是正确的做法：

Runtime rt=Runtime.getRuntime();
rt.exec("cmd.exe /c start <full path>");

例如：

Runtime rt=Runtime.getRuntime();
rt.exec("cmd.exe /c start C:/aa.txt");

Answer 6

如果你使用来自https://github.com/shikhar/sshj/的SSHJ

public static void main(String[] args) throws IOException {
    final SSHClient ssh = new SSHClient();
    ssh.loadKnownHosts();

    ssh.connect("10.x.x.x");
    try {
        //ssh.authPublickey(System.getProperty("root"));
        ssh.authPassword("user", "xxxx");
        final Session session = ssh.startSession();

        try {
            final Command cmd = session.exec("cd /backup; ls; ./backup.sh");
            System.out.println(IOUtils.readFully(cmd.getInputStream()).toString());
            cmd.join(5, TimeUnit.SECONDS);
            System.out.println("\n** exit status: " + cmd.getExitStatus());
        } finally {
            session.close();
        }
    } finally {
        ssh.disconnect();
    }
}