JAVA调用系统命令：python、shell等

实际项目开发场景中，可能会用到java项目调用系统命令的需求，如调用python或者shell脚本

可以参考如下例子，例子来源于ambari源码：

\ambari\ambari-server\src\main\java\org\apache\ambari\server\security\CertificateManager.java

 /**
   * Runs os command
   *
   * @return command execution exit code
   */
  protected int runCommand(String command) {
    String line = null;
    Process process = null;
    BufferedReader br= null;
    try {
      process = Runtime.getRuntime().exec(command);
      br = new BufferedReader(new InputStreamReader(
          process.getInputStream(), Charset.forName("UTF8")));

      while ((line = br.readLine()) != null) {
        LOG.info(line);
      }

      try {
        process.waitFor();
        ShellCommandUtil.logOpenSslExitCode(command, process.exitValue());
        return process.exitValue(); //command is executed
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      if (br != null) {
        try {
          br.close();
        } catch (IOException ioe) {
          ioe.printStackTrace();
        }
      }
    }

    return -;//some exception occurred

  }