为什么我电脑的IP地址总是在变？通常是127.0.0.1……？？是物理地址？还是……？？急急急
可以参看我的一个Java多客户程序：
[code=Java][/code]
//服务器端
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class MultipleWindowsDemo extends JFrame
  implements ActionListener {
  private JTextArea jta;
  private JButton jbtShowHistogram = new JButton("Show Histogram");
  private Histogram histogram = new Histogram();

  // Create a new frame to hold the histogram panel
  private JFrame histogramFrame = new JFrame();

  public MultipleWindowsDemo() {
  // Store text area in a scroll pane
  JScrollPane scrollPane = new JScrollPane(jta = new JTextArea());
  scrollPane.setPreferredSize(new Dimension(300, 200));
  jta.setWrapStyleWord(true);
  jta.setLineWrap(true);

  // Place scroll pane and button in the frame
  getContentPane().add(scrollPane, BorderLayout.CENTER);
  getContentPane().add(jbtShowHistogram, BorderLayout.SOUTH);

  // Register listener
  jbtShowHistogram.addActionListener(this);

  // Create a new frame to hold the histogram panel
  histogramFrame.getContentPane().add(histogram);
  histogramFrame.pack();
  histogramFrame.setTitle("Histogram");
  }

  /** Handle the button action */
  public void actionPerformed(ActionEvent e) {
  // Count the letters in the text area
  int[] count = countLetters();

  // Set the letter count to histogram for display
  histogram.showHistogram(count);

  // Show the frame
  histogramFrame.setVisible(true);
  }

  /** Count the letters in the text area */
  private int[] countLetters() {
  // Count for 26 letters
  int[] count = new int[26];

  // Get contents from the text area
  String text = jta.getText();

  // Count occurrence of each letter (case insensitive)
  for (int i = 0; i < text.length(); i++) {
  char character = text.charAt(i);

  if ((character >= 'A') && (character <= 'Z')) {
  count[(int)character - 65]++; // The ASCII for 'A' is 65
  }
  else if ((character >= 'a') && (character <= 'z')) {
  count[(int)character - 97]++; // The ASCII for 'a' is 97
  }
  }

  return count; // Return the count array
  }

  public static void main(String[] args) {
  MultipleWindowsDemo frame = new MultipleWindowsDemo();
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setTitle("MultipleWindowsDemo");
  frame.pack();
  frame.setVisible(true);
  }
}

//客户端
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Client extends JFrame implements ActionListener {
  // Text field for receiving radius
  private JTextField jtf = new JTextField();

  // Text area to display contents
  private JTextArea jta = new JTextArea();

  // IO streams
  private DataOutputStream outputToServer;
  private DataInputStream inputFromServer;

  public static void main(String[] args) {
  new Client();
  }

  public Client() {
  // Panel p to hold the label and text field
  JPanel p = new JPanel();
  p.setLayout(new BorderLayout());
  p.add(new JLabel("Enter radius"), BorderLayout.WEST);