Question

我正在尝试使用swing文本区域来模拟命令提示符。我正在启动服务器并将流传递到文本区域。问题是，我无法在文本区域中看到控制台输出。怎么解决？一旦进程停止（即服务器停止），我就能看到控制台输出，直到那时，我无法在文本区域看到控制台输出。粘贴代码块。我希望在服务器启动并运行时同时看到控制台输出。请帮忙。感谢。

注意：＆＃34;激活运行＆＃34;是启动服务器的命令。

private void startServerButtonMouseClicked(java.awt.event.MouseEvent evt) {                                               
    String[] command = {"CMD", "/C", "activator run"};
    ProcessBuilder processbuilder = new ProcessBuilder(command);
    processbuilder.directory(new File("D:\\temp"));
    try {
        Process process = processbuilder.start();
        InputStream is = process.getInputStream();
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        String line;
        while ((line = br.readLine()) != null) {
            //Appending the output to the text area
            cartServiceTextArea.append(line +"\n");
        }

        //Wait to get exit value
        try {
            int exitValue = process.waitFor();
            System.out.println("\n\nExit Value is " + exitValue);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    } catch (IOException ex) {
        Logger.getLogger(DevUtilsUI.class.getName()).log(Level.SEVERE, null, ex);
    }
}

Answer 1

您正在事件调度线程（EDT）中运行循环，更新GUI。直到您的方法返回，文本区域将不会更新。无论如何，这种方法是不正确的。

您需要做的是从单独的线程读取输出并从那里更新文本区域。你不应该阻止EDT。

package ant.test;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;

public class TextAreaCommandOutput extends JFrame {

    private static final long serialVersionUID = 1L;
    private JButton executeServer;
    private JTextArea textArea;

    public TextAreaCommandOutput() {
        super("Execute Command and Output to TextArea");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());
        textArea = new JTextArea(10, 80);
        add(new JScrollPane(textArea));
        executeServer = new JButton("Start Server");
        executeServer.addActionListener(new ActionListener() {
            @Override public void actionPerformed(ActionEvent e) {
                executeServer.setEnabled(false);
                new Thread(new Runnable() {
                    @Override public void run() {
                        startServerButtonMouseClicked();
                    }
                }).start();
            }
        });
        add(executeServer, BorderLayout.SOUTH);
        pack();
    }

    private void startServerButtonMouseClicked() {
        String[] command = { "ls", "-lR" };
        ProcessBuilder processbuilder = new ProcessBuilder(command);
        try {
            Process process = processbuilder.start();
            InputStream is = process.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line;
            while ((line = br.readLine()) != null) {
                // Appending the output to the text area
                textArea.append(line + "\n");
            }

            // Wait to get exit value
            try {
                int exitValue = process.waitFor();
                System.out.println("\n\nExit Value is " + exitValue);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } catch (IOException ex) {
            Logger.getLogger(TextAreaCommandOutput.class.getName()).log(Level.SEVERE, null, ex);
        }
        executeServer.setEnabled(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override public void run() {
                TextAreaCommandOutput f = new TextAreaCommandOutput();
                f.setVisible(true);
            }
        });
    }
}

流程输入流

1 个答案: