JFrame 中的 Java 多线程

Question

我希望这段代码在扫描器工作时与更新 JProgressBar 和 JTextArea 一起工作，但我不知道如何实现线程。可能吗？

这是我的代码:

更新:它现在是一个工作版本，具有“停止”功能。我添加了一个“breakPoint”变量以从 for 循环中跳出。

package main;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import javax.swing.JOptionPane;
import javax.swing.SwingWorker;

public class PortScanner extends javax.swing.JFrame {

    private doSomeStuff taskPortScanner;
    private boolean breakPoint;

    public PortScanner() {
        initComponents();
    }

    private void portScan() {

        int currentPort = 1;

        try {

            String hostname = hostNameTextField.getText();
            int timeOut = (Integer) timeOutSpinner.getValue();
            int minPort = Integer.parseInt(portMinTextField.getText());
            int maxPort = Integer.parseInt(portMaxTextField.getText());

            //set min and max value of progress bar
            jProgressBar1.setMinimum(minPort);
            jProgressBar1.setMaximum(maxPort);

            //print out the address
            InetAddress theAddress = InetAddress.getByName(hostname);
            resultTextArea.append("IP adress: " + theAddress + "\n\n");

            //check if port is open
            for (currentPort = minPort; currentPort <= maxPort; currentPort++) {

                //stop for loop
                if (breakPoint == true) {
                    System.out.println("Portscanning stopped.");
                    break;
                }

                try {

                    Socket socket = new Socket();
                    socket.connect(new InetSocketAddress(hostname, currentPort), timeOut);

                    //update textarea
                    resultTextArea.append("Service running on port " + currentPort + "\n");
                    socket.close();

                } catch (Exception ex) {
                    System.out.println(currentPort);
                }

                //update progressbar
                jProgressBar1.setValue(currentPort);
                jProgressBar1.repaint();
            }

        } catch (UnknownHostException ex) {
            JOptionPane.showMessageDialog(PortScanner.this, "Unknown hostname: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
        } catch (NumberFormatException ex) {
            JOptionPane.showMessageDialog(PortScanner.this, "Invalid format. " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
        } catch (Exception ex) {
            JOptionPane.showMessageDialog(PortScanner.this, "Error: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
        }
    }

    private class doSomeStuff extends SwingWorker<Void, Void> {

        @Override
        public Void doInBackground() throws Exception {
            portScan();
            return null;
        }

        @Override
        public void done() {
            //if thread is done enable start and clear buttons
            clearButton.setEnabled(true);
            startButton.setEnabled(true);
        }

    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        hostNameTextField = new javax.swing.JTextField();
        portMinTextField = new javax.swing.JTextField();
        jScrollPane1 = new javax.swing.JScrollPane();
        resultTextArea = new javax.swing.JTextArea();
        startButton = new javax.swing.JButton();
        clearButton = new javax.swing.JButton();
        portMaxTextField = new javax.swing.JTextField();
        jProgressBar1 = new javax.swing.JProgressBar();
        timeOutSpinner = new javax.swing.JSpinner();
        jLabel4 = new javax.swing.JLabel();
        stopButton = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setTitle("Simple port scanner");
        setResizable(false);

        jLabel1.setText("Hostname");

        jLabel2.setText("Timeout");

        jLabel3.setText("Port range");

        hostNameTextField.setToolTipText("Type a hostname like www.google.com");

        portMinTextField.setText("1");

        resultTextArea.setColumns(20);
        resultTextArea.setRows(5);
        jScrollPane1.setViewportView(resultTextArea);

        startButton.setText("Scan");
        startButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                startButtonActionPerformed(evt);
            }
        });

        clearButton.setText("Clear");
        clearButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                clearButtonActionPerformed(evt);
            }
        });

        portMaxTextField.setText("1000");

        jProgressBar1.setStringPainted(true);

        timeOutSpinner.setModel(new javax.swing.SpinnerNumberModel(15, 0, 999999, 1));

        jLabel4.setText("-");

        stopButton.setText("Stop");
        stopButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                stopButtonActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addContainerGap()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addComponent(jLabel2)
                                    .addComponent(jLabel1))
                                .addGap(21, 21, 21)
                                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                                    .addComponent(hostNameTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 112, javax.swing.GroupLayout.PREFERRED_SIZE)
                                    .addGroup(layout.createSequentialGroup()
                                        .addComponent(timeOutSpinner)
                                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))
                            .addGroup(layout.createSequentialGroup()
                                .addComponent(jLabel3)
                                .addGap(18, 18, 18)
                                .addComponent(portMinTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 62, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(jLabel4)
                                .addGap(12, 12, 12)
                                .addComponent(portMaxTextField, javax.swing.GroupLayout.PREFERRED_SIZE, 62, javax.swing.GroupLayout.PREFERRED_SIZE)))
                        .addGap(0, 0, Short.MAX_VALUE))
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jProgressBar1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap())
            .addGroup(layout.createSequentialGroup()
                .addGap(30, 30, 30)
                .addComponent(startButton)
                .addGap(18, 18, 18)
                .addComponent(stopButton)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 46, Short.MAX_VALUE)
                .addComponent(clearButton)
                .addGap(32, 32, 32))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(hostNameTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(timeOutSpinner, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel3)
                    .addComponent(portMinTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(portMaxTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel4))
                .addGap(18, 18, 18)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 157, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 23, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(startButton)
                    .addComponent(clearButton)
                    .addComponent(stopButton))
                .addContainerGap())
        );

        pack();
    }// </editor-fold>                        

    private void startButtonActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
        breakPoint = false;
        taskPortScanner = new doSomeStuff();
        taskPortScanner.execute();
        startButton.setEnabled(false);
        clearButton.setEnabled(false);
        System.out.println("Starting portscanner...");

    }                                           

    private void clearButtonActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:
        resultTextArea.setText(null);
        jProgressBar1.setValue(0);
        System.out.println("Clearing results...");
    }                                           

    private void stopButtonActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        breakPoint = true;
        startButton.setEnabled(true);
        clearButton.setEnabled(true);
    }                                          

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(PortScanner.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(PortScanner.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(PortScanner.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(PortScanner.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new PortScanner().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton clearButton;
    private javax.swing.JTextField hostNameTextField;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JProgressBar jProgressBar1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextField portMaxTextField;
    private javax.swing.JTextField portMinTextField;
    private javax.swing.JTextArea resultTextArea;
    private javax.swing.JButton startButton;
    private javax.swing.JButton stopButton;
    private javax.swing.JSpinner timeOutSpinner;
    // End of variables declaration                   
}

Answer 1

您需要考虑将长时间运行的扫描任务移出事件调度线程，以保持 UI 响应。看看使用 Swing Worker 来实现这一点。

http://en.wikipedia.org/wiki/SwingWorker#The_event_dispatching_thread_problem

http://docs.oracle.com/javase/tutorial/uiswing/concurrency/worker.html