数据报形式的无连接客户/服务器交互

package dataGram;

import java.awt.BorderLayout;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;

//服务器类
public class Server extends JFrame {
private static final long serialVersionUID = 1L;

private JTextArea displayArea;
private DatagramSocket socket;//用于发送分组

public Server() {
super("Server");

displayArea = new JTextArea();
getContentPane().add(new JScrollPane(displayArea), BorderLayout.CENTER);

setSize(400, 300);
setVisible(true);

try {
socket = new DatagramSocket(5000);//指定端口
} catch (SocketException socketException) {
// TODO: handle exception
socketException.printStackTrace();
System.exit(1);
}
}

private void waitForPackets() {
while (true) {
try {
byte data[] = new byte[100];
DatagramPacket receivePacket = new DatagramPacket(data,
data.length);//用于存储接收到的信息分组

socket.receive(receivePacket);//等待分组到达服务器,到达后，将信息存入参数中

displayMessage("/nPacket received:"
+ "/nFrom host: "
+ receivePacket.getAddress()
+ "/nHost port: "
+ receivePacket.getPort()
+ "/nLength: "
+ receivePacket.getLength()
+ "/nContaining:/n/t"
+ new String(receivePacket.getData(), 0, receivePacket
.getLength()));

sendPacketToClient(receivePacket);
} catch (IOException ioException) {
// TODO: handle exception
ioException.printStackTrace();
}
}
}

private void sendPacketToClient(DatagramPacket receivePacket)
throws IOException {//将信息返回给客户
displayMessage("/n/nEcho data to client...");

DatagramPacket sendPacet = new DatagramPacket(receivePacket.getData(),
receivePacket.getLength(), receivePacket.getAddress(),
receivePacket.getPort());

socket.send(sendPacet);//发送分组
displayMessage("Packet sent/n");
}

private void displayMessage(final String messageToDisplay) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
displayArea.append(messageToDisplay);
displayArea.setCaretPosition(displayArea.getText().length());
}
});
}

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Server applicaton=new Server();
applicaton.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
applicaton.waitForPackets();
}

}

package dataGram;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

//客户类
public class Client extends JFrame {
private static final long serialVersionUID = 1L;

private JTextField enterField;
private JTextArea displayArea;
private DatagramSocket socket;

public Client() {
super("Client");

Container container = getContentPane();

enterField = new JTextField("Type message here");
enterField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
try {
displayArea.append("/nSending packet containing: "
+ event.getActionCommand() + "/n");

String message = event.getActionCommand();
byte data[] = message.getBytes();//将用户输入的内容进行分组

DatagramPacket sendPacket = new DatagramPacket(data,
data.length, InetAddress.getLocalHost(), 5000);

socket.send(sendPacket);
displayArea.append("Packet sent/n");
displayArea
.setCaretPosition(displayArea.getText().length());
} catch (IOException ioException) {
// TODO: handle exception
displayMessage(ioException.toString() + "/n");
ioException.printStackTrace();
}
}
});

container.add(enterField, BorderLayout.NORTH);

displayArea = new JTextArea();
container.add(new JScrollPane(displayArea), BorderLayout.CENTER);

setSize(400, 300);
setVisible(true);

try {
socket = new DatagramSocket();
} catch (SocketException socketException) {
// TODO: handle exception
System.exit(1);
}
}

private void waitForPackets() {
while (true) {
try {
byte data[] = new byte[100];
DatagramPacket receivePacket = new DatagramPacket(data,
data.length);

socket.receive(receivePacket);

displayMessage("/nPacket received: "
+ "/nFrom host: "
+ receivePacket.getAddress()
+ "/nHost port: "
+ receivePacket.getPort()
+ "/nLength: "
+ receivePacket.getLength()
+ "/nContaiing:/n/t"
+ new String(receivePacket.getData(), 0, receivePacket
.getLength()));
} catch (IOException ioException) {
// TODO: handle exception
displayMessage(ioException.toString()+"/n");
ioException.printStackTrace();
}
}
}

private void displayMessage(final String messageToDisplay) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
displayArea.append(messageToDisplay);
displayArea.setCaretPosition(displayArea.getText().length());
}
});
}

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Client application=new Client();
application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
application.waitForPackets();
}

}