如何使用 ProcessBuilder 与 CLI 程序持续交互

我经常使用通过 docker 容器访问的 CLI 程序。进入容器后，我就可以开始使用相关的 CLI 程序。我遇到的问题是我想继续与同一个命令行实例交互。基本上我正在尝试创建一个将在 CLI 程序“之上”运行的 GUI 程序。我只是不知道如何继续向同一个 CLI 实例发送命令：

List<String> command = new ArrayList<String>();
command.add("cmd.exe" );
command.add("/c");
command.add("docker-compose up -d");
System.out.println(command);

ProcessBuilder builder = new ProcessBuilder(command);
builder.inheritIO();
Map<String, String> environ = builder.environment();

Process process = builder.start();
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null) {
    System.out.println(line);
}
command.clear();
command.add("cmd.exe" );
command.add("/c");
command.add("docker ps");
System.out.println(command);

process = builder.start();
is = process.getInputStream();
isr = new InputStreamReader(is);
br = new BufferedReader(isr);
while ((line = br.readLine()) != null) {
    System.out.println(line);
}

但这并没有按照我希望的方式工作。在上面，您会看到我正在运行两个命令：docker-compose up -d进而docker ps。但我不认为它们在同一个实例中运行。因此，如果我要更改第一个命令中的目录，它不会记住第二个命令的目录。

另外，它似乎以与代码中的顺序相反的顺序运行我的命令。

类的实例ProcessBuilder在我看来，这些都是短暂的。我不认为每次创建新进程时创建一个新实例会浪费内存或其他资源 - 但我只是猜测。

无论如何，要重新使用ProcessBuilder实例为了执行多个进程，您只需使用它的方法，例如command(String...) https://docs.oracle.com/javase/8/docs/api/java/lang/ProcessBuilder.html#command-java.lang.String...-

我写了一个小Swing允许用户输入 [操作系统] 命令并显示该命令的输出的应用程序。它不是生产准备好了，但我希望这足以让你继续前进。

请注意，创建和处理Process https://docs.oracle.com/javase/8/docs/api/java/lang/Process.htmljava代码既不简单也不直观。文章当 Runtime.exec() 不会时 https://www.javaworld.com/article/2071275/when-runtime-exec---won-t.html对我帮助很大。这是一篇古老的文章，但仍然具有相关性（同样，在我看来）。只需替换对类的引用Runtime在类文章中ProcessBuilder由于文章之前写过ProcessBuilder已添加到 JDK 中。

这是我的应用程序的代码。请参阅上述文章以了解ProcessBuilder相关代码。为了了解Swing代码，我推荐教程使用 JFC/Swing 创建 GUI https://docs.oracle.com/javase/tutorial/uiswing/index.html

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

public class ProcExec implements ActionListener, Runnable {
    private static final String CLEAR = "Clear";
    private static final String EXIT = "Exit";
    private static final String RUN = "Run";

    private JTextArea commandOutput;
    private JTextArea textArea;
    private ProcessBuilder procBuilder;

    public ProcExec() {
        procBuilder = new ProcessBuilder();
    }

    public void actionPerformed(ActionEvent actionEvent) {
        String actionCommand = actionEvent.getActionCommand();
        if (CLEAR.equals(actionCommand)) {
            textArea.setText("");
        }
        else if (EXIT.equals(actionCommand)) {
            System.exit(0);
        }
        else if (RUN.equals(actionCommand)) {
            try {
                execute();
            }
            catch (Exception x) {
                x.printStackTrace();
            }
        }
    }

    public void run() {
        createAndDisplayGui();
    }

    private void createAndDisplayGui() {
        JFrame frame = new JFrame("Process Executor");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(createTopPanel(), BorderLayout.PAGE_START);
        frame.add(createCommandPanel(), BorderLayout.CENTER);
        frame.add(createButtonsPanel(), BorderLayout.PAGE_END);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private JButton createButton(String text, int mnemonic, String tooltip) {
        JButton button = new JButton(text);
        button.setMnemonic(mnemonic);
        button.setToolTipText(tooltip);
        button.addActionListener(this);
        return button;
    }

    private JPanel createButtonsPanel() {
        JPanel buttonsPanel = new JPanel();
        buttonsPanel.add(createButton(RUN, KeyEvent.VK_R, "Run entered command."));
        buttonsPanel.add(createButton(CLEAR, KeyEvent.VK_C, "Removes entered command."));
        buttonsPanel.add(createButton(EXIT, KeyEvent.VK_X, "Exit application."));
        return buttonsPanel;
    }

    private JSplitPane createCommandPanel() {
        textArea = new JTextArea(30, 40);
        textArea.setLineWrap(true);
        textArea.setWrapStyleWord(true);
        JScrollPane cmdScrollPane = new JScrollPane(textArea);
        commandOutput = new JTextArea(30, 80);
        JScrollPane outputScrollPane = new JScrollPane(commandOutput);
        JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
                                              cmdScrollPane,
                                              outputScrollPane);
        return splitPane;
    }

    private JPanel createTopPanel() {
        JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));
        JLabel label = new JLabel("Enter a command...");
        topPanel.add(label);
        return topPanel;
    }

    private int execute() throws IOException, InterruptedException {
        commandOutput.setText("");
        String raw = textArea.getText();
        String[] words = raw.split(" ");
        String[] command = new String[words.length + 2];
        command[0] = "cmd.exe";
        command[1] = "/C";
        System.arraycopy(words, 0, command, 2, words.length);
        procBuilder.command(command);
        Process proc = procBuilder.start();
        ProcHandler stdout = new ProcHandler(proc.getInputStream());
        ProcHandler stderr = new ProcHandler(proc.getErrorStream());
        Thread stdoutThread = new Thread(stdout);
        stdoutThread.start();
        Thread stderrThread = new Thread(stderr);
        stderrThread.start();
        int status = proc.waitFor();
        stderrThread.join();
        stdoutThread.join();
        return status;
    }

    private class ProcHandler implements Runnable {
        private BufferedReader streamReader;

        public ProcHandler(InputStream is) {
            InputStreamReader isr = new InputStreamReader(is);
            streamReader = new BufferedReader(isr);
        }

        public void run() {
            try {
                String line = streamReader.readLine();
                while (line != null) {
                    SwingUtilities.invokeLater(new StreamLine(line));
                    line = streamReader.readLine();
                }
            }
            catch (Exception x) {
                throw new RuntimeException("Stream reading failed.", x);
            }
        }
    }

    private class StreamLine implements Runnable {
        private final String text;

        public StreamLine(String txt) {
            text = txt + "\n";
        }

        public void run() {
            ProcExec.this.commandOutput.append(text);
        }
    }

    public static void main(String[] args) {
        ProcExec instance = new ProcExec();
        EventQueue.invokeLater(instance);
    }
}