如何从 Java 向 sudo 提供 root 密码？

Question

我正在尝试编写一个小型 Java 应用程序来覆盖我的 /etc/resolv.conf 文件（我在 Ubuntu 12.04 上）。为此，我需要提供我的root 密码：

myUser@myMachine:~$ sudo vim /etc/resolv.conf 
[sudo] password for myUser: *****

所以这样做的过程分为三个步骤：

1. 在终端输入sudo vim /etc/resolv.conf
2. 终端要求我输入root 密码
3. 我输入密码并按[Enter]

根据我研究过的所有内容，我可以使用以下内容来执行上面的第 1 步：

try {
    String installTrickledCmd = "sudo vim /etc/resolv.conf";
    Runtime runtime = Runtime.getRuntime();
    Process proc = runtime.exec(installTrickledCmd);
}
catch(Throwable throwable) {
    throw new RuntimeException(throwable);
}

但是当它执行时，shell 会提示我的 Java 进程输入密码。我不确定如何等待（上面的步骤#2）然后将我的密码提供回shell（上面的步骤#3）。提前致谢。

Answer 1

你试过 -S 吗？

$echo mypassword | sudo -S vim /etc/resolv.conf

来自男人：

The -S (stdin) option causes sudo to read the password from the standard input 
instead of the terminal device.  The password must be followed by a newline 
character.

Answer 2

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

public class Test1 {

  public static void main(String[] args) throws Exception {
    String[] cmd = {"sudo","-S", "ls"};
    System.out.println(runSudoCommand(cmd));
  }

  private static int runSudoCommand(String[] command) throws Exception {

    Runtime runtime =Runtime.getRuntime();
    Process process = runtime.exec(command);
    OutputStream os = process.getOutputStream();
    os.write("harekrishna\n".getBytes());
    os.flush();
    os.close();
    process.waitFor();
    String output = readFile(process.getInputStream());
    if (output != null && !output.isEmpty()) {
      System.out.println(output);
    }
    String error = readFile(process.getErrorStream());
    if (error != null && !error.isEmpty()) {
      System.out.println(error);
    }
    return process.exitValue();
  }

  private static String readFile(InputStream inputStream) throws Exception {
    if (inputStream == null) {
      return "";
    }
    StringBuilder sb = new StringBuilder();
    BufferedReader bufferedReader = null;
    try {
      bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
      String line = bufferedReader.readLine();
      while (line != null) {
        sb.append(line);
        line = bufferedReader.readLine();
      }
      return sb.toString();
    } finally {
      if (bufferedReader != null) {
        bufferedReader.close();
      }
    }
  }

}

灵感来自 Viggiano 的回答。