Question

我的代码应该捕获网络流量并将其显示在textarea上，但它没有这样做。请查看代码并检查是否有任何更正。

public class NewClass {

    public static JTextArea textarea = new JTextArea();

    NewClass() throws IOException{

        JButton capture = new JButton("Capture");
        JFrame frame = new JFrame();        
        JScrollPane scroll;
        NetworkInterface[] NI= JpcapCaptor.getDeviceList();
        int INDEX=0;
        JpcapCaptor JPCAP = JpcapCaptor.openDevice(NI[INDEX], 65536, false, 20);

        frame.setSize(700,500);
        frame.setLocation(200,200);
        frame.getContentPane().setLayout(null);
        frame.setBackground(Color.yellow);        

        textarea.setEditable(false);
        textarea.setFont(new Font("Tahoma",0,14));
        textarea.setForeground(Color.RED);
        textarea.setLineWrap(true);
        //textarea.setBackground(Color.WHITE);

        scroll = new JScrollPane();
        scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        scroll.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        scroll.setViewportView(textarea);

        frame.getContentPane().add(scroll);
        scroll.setBounds(10,16,740,290);

        capture.setBackground(Color.RED);
        capture.setForeground(Color.GREEN);
        frame.getContentPane().add(capture);

        handler ob = new handler();
        capture.addActionListener(ob);
        capture.setBounds(100, 400, 90, 25);

        frame.setVisible(true);
    }

    public class handler implements ActionListener{
        public void actionPerformed(ActionEvent Event){

            class Print implements PacketReceiver{
                public void receivePacket(Packet packet){
                    String info = packet.toString();
                    textarea.append(info);
                    //System.out.println(packet.toString());
                }                    
            }
    }
}

Answer 1

我的代码应该捕获网络流量并将其显示在textarea上，但它没有这样做。请查看代码并检查是否有任何更正。

好吧，你的处理程序的actionPerformed方法并没有真正做任何事情。它定义了一个内部类，但没有创建该类的对象，也没有对它做任何事情：

public class handler implements ActionListener {
  public void actionPerformed(ActionEvent Event) {
     class Print implements PacketReceiver {
        public void receivePacket(Packet packet) {
           String info = packet.toString();
           textarea.append(info); // System.out.println(packet.toString());
        }
     }
  }
}

考虑创建一个Print类的对象（一个类的可怕名称，因为已经存在一个属于核心Java库的Print类）并且让这个Print对象做一些有用的东西，也许接收数据包（不过它应该是要做到这一点）。注意不要在主Swing线程，EDT中执行长时间运行的进程，否则你将冻结你的Swing GUI。

修改
如，

// note that class names such as "Handler" should begin with a capital letter. public class Handler implements ActionListener { public void actionPerformed(ActionEvent Event) { class Print implements PacketReceiver { public void receivePacket(Packet packet) { String info = packet.toString(); textarea.append(info); // System.out.println(packet.toString()); } } // create a Print instance so that it can do something: final Print myPrint = new Print(); // do something with myPrint here so that it gets packets and displays them // I suspect that you'll likely want to do this in a background thread // using a SwingWorker } }

Answer 2

因为气垫船说你除了定义一个内部阶级之外别无所求。你在这里缺少的是从JPCAP类调用processPacket（）或loopPacket（）。所以我所说的是以下内容：

public class handler implements ActionListener{
  public void actionPerformed(ActionEvent Event){

    class Print implements PacketReceiver{
        public void receivePacket(Packet packet){
            String info = packet.toString();
            textarea.append(info);                                            
        }

    }

    // this captures 10 packets .
    JPCAP.processPacket(10,new Print());
  }
}

JButton不工作[捕获网络流量]

2 个答案: