**这是两个同行之间聊天的简单代码。据我说，代码做了它应该做的，但我在解决这个 SocketException 错误时遇到了困难。在我进行最后一次修改之前，这段代码运行良好。现在我发现很难追踪错误。
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
import java.util.*;
import java.net.*;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class UDPchat extends Thread implements ActionListener
{
JFrame f;
JPanel p;
JTextField text;
JButton b;
JTextArea ta;
private final static String newline = "\n";
private final static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
int porttor=7777; // port to send/receive datagrams on
//int porttos=5555;
String remoteIPaddress= ("127.0.0.1"); // IP to send datagrams
public UDPchat() throws Exception
{
start(); // start thread to receive and display datagrams
f=new JFrame("CHAT WINDOW");
p= new JPanel();
text = new JTextField();
text.setColumns(25);
b = new JButton("SEND");
b.addActionListener(this);
ta = new JTextArea("Chat messages",20,50);
ta.setEditable(false);
f.setLayout(new FlowLayout());
p.add(text,BorderLayout.NORTH);
p.add(b,BorderLayout.SOUTH);
f.setLayout(new BorderLayout());
f.add(ta,BorderLayout.NORTH);
f.add(p,BorderLayout.SOUTH);
f.setSize(400, 400);
f.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e)
{
try
{
String s = text.getText(); // read a String
text.setText(" ");
ta.append(newline);
ta.append(s);
//System.out.println("Sending to " + remoteIPaddress + " socket " + port + " data: " + s);
byte[] data = s.getBytes(); // convert to byte array
DatagramSocket theSocket = new DatagramSocket(); // create datagram socket and the datagram
DatagramPacket theOutput = new DatagramPacket(data, data.length, InetAddress.getLocalHost(), 5555);
theSocket.send(theOutput);
}
catch(Exception et)
{
System.out.println("Error sending datagram" + et);
}
}
// thread run method, receives datagram and display contents as a string
public void run()
{
try
{
// open DatagramSocket to receive
DatagramSocket ds = new DatagramSocket(7777);
// loop forever reading datagrams from the DatagramSocket
while (true)
{
byte[] buffer = new byte[65507]; // array to put datagrams in
DatagramPacket dp = new DatagramPacket(buffer, buffer.length); // DatagramPacket to hold the datagram
try {
ds.receive(dp);
} catch (IOException e) {
// TODO Auto-generated catch block
System.err.println("chat error2 " + e);
} // wait for next datagram
String s = new String(dp.getData(),0,dp.getLength()); // get contents as a String
System.out.println("UDP datagram length " + s.length()+ " from IP " + dp.getAddress() + " received: " + s );
ta.append(newline);
ta.append(s);
}
}
catch (SocketException se)
{
System.err.println("chat error1 " + se);
}
//catch (IOException se) {System.err.println("chat error2 " + se);}
//System.exit(1); // exit on error
}
public static void main(String args[]) throws Exception
{
UDPchat c=new UDPchat();
}
}