网络通信--UDP
[TOC]
UDP实现收发数据
接收数据
(1)使用DatagramSocket(int port )创建一个数据包套接字，绑定到指定端口
(2)使用DataPacket(byte[] buf,int length)创建字节数组来接收数据包
(3)使用DatagramSocket类的receive()方法发送数据包
public static void main(String[] args) {
try {
//接收数据时必须指定端口
DatagramSocket socket=new DatagramSocket(8080);
byte [] array=new byte[1024];
DatagramPacket pack=new DatagramPacket(array, 1024);
socket.receive(pack);
//把接收到的数据存入数组
byte [] data=pack.getData();
//将数组转化成字符串打印输出
System.out.println(new String(data));
//System.out.println(new String(array,0,pack.getLength())); 用getLength()得到要接受或发送数据的长度
//最后一定要将流关闭
socket.close();
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}发送数据
(1)使用DatagramSocket( )创建一个数据包套接字
(2)使用DataPacket(byte[] buf,int offset,int length,InetAddress address,port)创建要发送的数据包
(3)使用DatagramSocket类的send()方法发送数据包
public static void main(String[] args) {
try {
//发送时不用指定端口
DatagramSocket send=new DatagramSocket();
String a="duyongkang";
byte[]array=a.getBytes();
//指定要发送到的主机，数据和端口号
DatagramPacket pack=new DatagramPacket(array, array.length,InetAddress.getLocalHost(),8080);
send.send(pack);//发送数据
System.out.println("已经发送数据");
send.close();//最后将流关闭
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}UDP相互交流
先运行接收,在运行发送
接收数据代码部分
//接收数据代码部分
public static void main(String[] args) {
try {
DatagramSocket socket=new DatagramSocket(8080);
DatagramPacket pack=null;
DatagramSocket send=new DatagramSocket();
Scanner input=new Scanner(System.in);
DatagramPacket pac=null;
while(true){
byte [] array=new byte[1024];
pack=new DatagramPacket(array, 1024);
socket.receive(pack);
byte [] data=pack.getData();
//System.out.println(new String(array,0,pack.getLength())); 用getLength()得到要接受或发送数据的长度
System.out.println(new String(data));
String str=input.next();
byte[]array1=str.getBytes();
pac=new DatagramPacket(array1, array1.length,InetAddress.getByName("192.168.0.31"),8081);
send.send(pac);
System.out.println("已经发送数据");
}
//socket.close();
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}发送数据代码部分
public static void main(String[] args) {
try {
DatagramSocket socket=new DatagramSocket(8081);
DatagramPacket pack=null;
DatagramSocket send=new DatagramSocket();
Scanner input=new Scanner(System.in);
DatagramPacket pac=null;
while(true){
String str=input.next();
byte[]array=str.getBytes();
//用getByName得到ip地址
pac=new DatagramPacket(array, array.length,InetAddress.getByName("192.168.0.31"),8080);
send.send(pac);
System.out.println("已经发送数据");
byte [] array1=new byte[1024];
pack=new DatagramPacket(array1, 1024);
socket.receive(pack);
byte [] data=pack.getData();
System.out.println(new String(data));
}
//send.close();//最后将流关闭
} catch (SocketException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
在界面上聊天
//**********************************************
public class MyClientRead implements Runnable{
private MyClient client;
public MyClientRead(MyClient client){
this.client=client;
}
@Override
public void run() {
while(true){
client.read();
}
}
}
//*******************************************
public class MyServerRead implements Runnable{
private MyServer server;
private Socket socket;
public MyServerRead(MyServer server,Socket socket){
this.server=server;
this.socket=socket;
}
@Override
public void run() {
while(server.isRunning()){
server.read(socket);
}
}
}
//*********************************************
public class MyClient extends JFrame {
private JPanel contentPane;
private JList list;
private JTextArea textArea;
private Socket socket;
private DefaultListModel<String> modle;
/** * Launch the application. */
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MyClient frame = new MyClient();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/** * Create the frame. */
public MyClient() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JButton btnNewButton = new JButton("发送");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
write();
}
});
btnNewButton.setBounds(314, 201, 93, 51);
contentPane.add(btnNewButton);
textArea = new JTextArea();
textArea.setBounds(41, 201, 240, 51);
contentPane.add(textArea);
list = new JList();
list.setBounds(41, 25, 240, 157);
modle=new DefaultListModel<>();
list.setModel(modle);
contentPane.add(list);
JButton btnNewButton_1 = new JButton("连接服务器");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
System.out.println("连接服务器");
socket=new Socket("localhost", 8080);
System.out.println("连接服务器成功");
Thread t=new Thread(new MyClientRead(MyClient.this));
t.start();
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
btnNewButton_1.setBounds(314, 47, 93, 42);
contentPane.add(btnNewButton_1);
}
public void write(){
try {
OutputStream os=socket.getOutputStream();
BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(os));
String words= textArea.getText();
bw.write(words+"\n");
modle.addElement(words);
textArea.setText("");
bw.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void read() {
try {
InputStream is = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String line = br.readLine();
modle.addElement(""+line);//让服务器说的话出现在客户端的JList list上
System.out.println(line);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//****************************************
public class MyServer extends JFrame {
private JPanel contentPane;
private ArrayList<Socket> sockets;
private JTextArea textArea;
private boolean isRunning = true;
private JButton btnNewButton_1;
private JList list;
private DefaultListModel<String> modle;
public boolean isRunning() {
return isRunning;
}
public void setRunning(boolean isRunning) {
this.isRunning = isRunning;
}
/** * Launch the application. */
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MyServer frame = new MyServer();//????????????????????????????????????
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/** * Create the frame. */
public MyServer() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 481, 358);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JButton btnNewButton1 = new JButton("开启服务器 ");
btnNewButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
isRunning = true;
//这个线程等待客户端链接服务器
new Thread(new Runnable() {
@Override
public void run() {
try {
ServerSocket server = new ServerSocket(8080);
System.out.println("服务器启动");
sockets = new ArrayList<>();
while (isRunning) {
Socket socket = server.accept();//等待客户端连接进来
sockets.add(socket);
//下边这个线程专门用来等待socket发送过来的信息
//????????????????
Thread t = new Thread(new MyServerRead(MyServer.this,socket));
t.start();
System.out.println("有客户端连接");
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).start();
// ;
}
});
btnNewButton1.setBounds(362, 36, 93, 45);
contentPane.add(btnNewButton1);
textArea = new JTextArea();
textArea.setBounds(39, 250, 303, 45);
contentPane.add(textArea);
btnNewButton_1 = new JButton("发送给客户");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//modle是干啥的?????????????
modle.addElement(textArea.getText());
write();
}
});
btnNewButton_1.setBounds(352, 250, 93, 45);
contentPane.add(btnNewButton_1);
modle = new DefaultListModel<>();
list = new JList();
list.setModel(modle);
list.setBounds(39, 21, 303, 219);
contentPane.add(list);
}
public void read(Socket socket) {
if (socket.isConnected()) {
try {
InputStream is = socket.getInputStream();//只能读字节
InputStreamReader isr = new InputStreamReader(is);//读字符
BufferedReader br = new BufferedReader(isr);//将字符换成一行
String line = br.readLine();
//让客户端的话出现在服务器的JList list上
modle.addElement(socket.getInetAddress().getHostName() + " " + line);
System.out.println(line);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else {
sockets.remove(socket);
}
}
/** * 这里是服务器发送消息 */
public void write() {
try {
for (Socket socket : sockets) {
OutputStream os = socket.getOutputStream();
OutputStreamWriter osw = new OutputStreamWriter(os);
BufferedWriter bw = new BufferedWriter(osw);
String words = textArea.getText();
System.out.println("服务器发送消息");
bw.write(words + "\n");
bw.flush();
}
textArea.setText("");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}