public class ChatServer {public static void main(String[] args) {try {ServerSocket serverSocket=new ServerSocket(44432);Socket socket=serverSocket.accept();//获取客户端的连接信息BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(socket.getInputStream()));//client 的输入内容PrintWriter printWriter =new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));//往client输出内容System.out.println("client say:"+bufferedReader.readLine());Scanner bufferedReader1=new Scanner(System.in);//控制台输入内容String message=bufferedReader1.next();while(!message.equals("end")) {printWriter.println(message);//send message to client
                printWriter.flush();System.out.println("client say:"+bufferedReader.readLine());// get message from clientmessage=bufferedReader1.next();}bufferedReader.close();printWriter.close();bufferedReader1.close();} catch (IOException e) {e.printStackTrace();}}
}

public class ChatClient {public static void main(String[] args) {try {Socket socket=new Socket("127.0.0.1",44432);//获取服务端的唯一标识PrintWriter printWriter=new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));//BufferedWriter流也可以BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(socket.getInputStream()));BufferedReader bufferedReader1=new BufferedReader(new InputStreamReader(System.in));String message=bufferedReader1.readLine();while (!message.equals("end")){printWriter.write(message+"\r\n");//加\r\n,因为读取时是用readLine方式 ，等同于println方式printWriter.flush();//必须flush,不然另一端读不到。。。System.out.println("server say:"+bufferedReader.readLine());message=bufferedReader1.readLine();}bufferedReader.close();bufferedReader1.close();} catch (IOException e) {e.printStackTrace();}}
}

public class UdpServer {public static void main(String[] args) {byte[] buf=new byte[1024];//存储接受数据报的容器DatagramPacket datagramPacket=new DatagramPacket(buf,buf.length);//数据报内容写入容器try {DatagramSocket datagramSocket=new DatagramSocket(44423);while (true){datagramSocket.receive(datagramPacket);//接收发送方的数据报ByteArrayInputStream byteArrayInputStream=new ByteArrayInputStream(buf);DataInputStream dataInputStream=new DataInputStream(byteArrayInputStream);System.out.println("clint say:"+dataInputStream.readDouble());}} catch (Exception e) {e.printStackTrace();}}
}

public class UdpClient {public static void main(String[] args) {double n=10000.00;try {ByteArrayOutputStream byteArrayOutputStream=new ByteArrayOutputStream();DataOutputStream dataOutputStream=new DataOutputStream(byteArrayOutputStream);dataOutputStream.writeDouble(n);//创建代有数据报内容和目的地址DatagramPacket datagramPacket=new DatagramPacket(byteArrayOutputStream.toByteArray(),byteArrayOutputStream.toByteArray().length,new InetSocketAddress("127.0.0.1",44423));DatagramSocket datagramSocket=new DatagramSocket(53421);//指定发送的端口
            datagramSocket.send(datagramPacket);} catch (Exception e) {e.printStackTrace();}}
}