从进程打印Java InputStream

UPDATE: I found a crucial part to why this probably isn't working! I used System.setOut(out); where out is a special PrintStream to a JTextArea

这是代码，但我遇到的问题是，只有当我结束这个过程时，信息才会被打印出来。

 public Constructor() { main(); } private void main() { btnStart.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { try { ProcessBuilder builder = new ProcessBuilder("java", textFieldMemory.getText(), "-jar", myJar); Process process = builder.start(); InputStream inputStream = process.getInputStream(); BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream), 1); String line; while ((line = bufferedReader.readLine()) != null) { System.out.println(line); } inputStream.close(); bufferedReader.close(); } catch (IOException ioe) { ioe.printStackTrace(); } } }); } 

电stream输出：

 Line 1 Line 2 Line 3 Line 4 Line 5 

这是正确的输出，但是当我结束这个过程时，它只是被打印成一个大块。

有谁知道这个问题是什么？ 如果是的话，你可以帮忙向我解释为什么发生这种情况，先谢谢你。

Answer 1

在一个单独的线程中处理进程的输出stream可能有帮助。 您还希望在继续执行逻辑之前明确地等待进程结束：

 ProcessBuilder builder = new ProcessBuilder("java", textFieldMemory.getText(), "-jar", myJar); final Process process = builder.start(); final Thread ioThread = new Thread() { @Override public void run() { try { final BufferedReader reader = new BufferedReader( new InputStreamReader(process.getInputStream())); String line = null; while ((line = reader.readLine()) != null) { System.out.println(line); } reader.close(); } catch (final Exception e) { e.printStackTrace(); } } }; ioThread.start(); process.waitFor(); 

Answer 2

基本上，从几乎没有什么信息，这听起来像你执行的过程，并从事件调度线程内读取InputStream 。

任何东西阻止EDT将阻止它处理重新绘制请求，相反，你应该使用像SwingWorker这样的function，允许你从EDT更新UI。

查看Swing中的并发性以获取更多详细信息

 import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.Graphics; import java.awt.Graphics2D; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.util.List; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.SwingWorker; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; public class PBDemo { public static void main(String[] args) throws Exception { new PBDemo(); } public PBDemo() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new TestPane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class TestPane extends JPanel { public TestPane() { setLayout(new BorderLayout()); JTextArea ta = new JTextArea(); add(new JScrollPane(ta)); new ProcessWorker(ta).execute(); } @Override public Dimension getPreferredSize() { return new Dimension(200, 200); } } public interface Consumer { public void consume(String value); } public class ProcessWorker extends SwingWorker<Integer, String> implements Consumer { private JTextArea textArea; public ProcessWorker(JTextArea textArea) { this.textArea = textArea; } @Override protected void process(List<String> chunks) { for (String value : chunks) { textArea.append(value); } } @Override protected Integer doInBackground() throws Exception { // Forced delay to allow the screen to update Thread.sleep(5000); publish("Starting...\n"); int exitCode = 0; ProcessBuilder pb = new ProcessBuilder("java.exe", "-jar", "HelloWorld.jar"); pb.directory(new File("C:\\DevWork\\personal\\java\\projects\\wip\\StackOverflow\\HelloWorld\\dist")); pb.redirectError(); try { Process pro = pb.start(); InputConsumer ic = new InputConsumer(pro.getInputStream(), this); System.out.println("...Waiting"); exitCode = pro.waitFor(); ic.join(); System.out.println("Process exited with " + exitCode + "\n"); } catch (Exception e) { System.out.println("sorry" + e); } publish("Process exited with " + exitCode); return exitCode; } @Override public void consume(String value) { publish(value); } } public static class InputConsumer extends Thread { private InputStream is; private Consumer consumer; public InputConsumer(InputStream is, Consumer consumer) { this.is = is; this.consumer = consumer; start(); } @Override public void run() { try { int in = -1; while ((in = is.read()) != -1) { // System.out.print((char) in); consumer.consume(Character.toString((char)in)); } } catch (IOException exp) { exp.printStackTrace(); } } } }