求帮忙改改，使能运行！！！

package client;

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.AbstractButton;

public class Client extends JFrame {

private JTextField nameField1,mailField2,field;
private JRadioButton maleButton,womenButton;
private JComboBox sdept;
private ButtonGroup radioGroup;
private JButton button;
private JTextArea displayArea,displayArea2;
private DatagramSocket socket;
// set up GUI and DatagramSocket
public Client()
{ super( "客户应用" );
Container container = getContentPane();
container.setLayout(new FlowLayout());

Box box1=Box.createHorizontalBox();
JLabel label1=new JLabel("姓名:");
box1.add(label1);
nameField1= new JTextField(10);
box1.add(nameField1);
container.add(box1);

Box box2=Box.createHorizontalBox();
JLabel label2=new JLabel("性别：");
box2.add(label2);
maleButton=new JRadioButton("男",true);
box2.add(maleButton);
womenButton=new JRadioButton("女",false);
box2.add(womenButton);

radioGroup= new ButtonGroup();
radioGroup.add(maleButton);
radioGroup.add(womenButton);

container.add(box2);

JLabel label3=new JLabel("电子邮箱：");
container.add(label3);
mailField2=new JTextField(20);
container.add(mailField2);

Box box3=Box.createHorizontalBox();
JLabel label4=new JLabel("备注：");
box3.add(label4);
displayArea=new JTextArea(5,12);
box3.add(new JScrollPane( displayArea ));
button=new JButton("提交");
box3.add(button);
container.add(box3);

Box box4=Box.createHorizontalBox();

displayArea2=new JTextArea(5,13);
box4.add(displayArea2);
container.add(box4);
setSize( 300,500);
setVisible( true );

  button .addActionListener(
  new ActionListener() { 
     public void actionPerformed( ActionEvent event )
     {  // create and send packet
        try {
            // get message from textfield and convert to byte array
            String string=new String();
               string ="姓名：" +nameField1.getText() + "\n"+"性别：" +radioGroup.getElements().nextElement()+ "电子邮箱："+mailField2.getText()+"备注："+displayArea.getText();


           String message = string;
           byte data[] = message.getBytes();
            // create sendPacket
           DatagramPacket sendPacket = new DatagramPacket( data, 
              data.length, InetAddress.getLocalHost(), 5000 );
           socket.send( sendPacket ); // send packet
        }               
        catch ( IOException ioException ) {
           ioException.printStackTrace();
        }
     } // end actionPerformed
  } // end inner class

); // end call to addActionListener

// create DatagramSocket for sending and receiving packets
try {
socket = new DatagramSocket();
}
// catch problems creating DatagramSocket
catch( SocketException socketException ) {
socketException.printStackTrace();
System.exit( 1 );
}
}
// wait for packets to arrive from Server, display packet contents
private void waitForPackets()
{
while ( true ) { // loop forever

  // receive packet and display contents
  try {
     // set up packet
     byte data[] = new byte[ 100 ];
     DatagramPacket receivePacket = new DatagramPacket( 
        data, data.length );
     socket.receive( receivePacket ); // wait for packet
     // display packet contents
     displayMessage( "服务器收到的信息是："+ new String( receivePacket.getData(), 
           0, receivePacket.getLength() ) +
        "\n长度为: " + receivePacket.getLength()+ 
        "\n\n对方主机: " + receivePacket.getAddress() + 
        "\n端口号: " + receivePacket.getPort() ); 
  } 
  // process problems receiving or displaying packet
  catch( IOException exception ) {
     displayMessage( exception.toString() + "\n" );
     exception.printStackTrace();
  }

} // end while
}
// displayArea in the event-dispatch thread
private void displayMessage( final String messageToDisplay )
{
// display message from event-dispatch thread of execution
SwingUtilities.invokeLater(
new Runnable() { // inner class to ensure GUI updates properly
public void run() // updates displayArea
{ displayArea2.append( messageToDisplay );

}
} // end inner class
);
}

public static void main( String args[] )
{
Client application = new Client();
application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
application.waitForPackets();
}

}

[code="java"]
string ="姓名：" +nameField1.getText() + "\n"+"性别：" +(radioGroup.getElements().nextElement().getModel().isSelected()? "男":"女")+ " 电子邮箱："+mailField2.getText()+"备注："+displayArea.getText();

[/code]
可以了！

。。。。
这个就可以运行啊，没有错啊。

不过这个应该不全吧。你的类名是client
那么server呢？

楼主的代码有点乱，要改进！我帮你改了下，我测试是可以用的！希望对你有帮助！