[网络协议]网络编程tcp-udp

1. tcp

public class Client {
    public static void main(String[] args) throws Exception{
        while (true){
            System.out.println("输入1查看新消息\n输入2发送消息");
            Scanner scanner = new Scanner(System.in);
            int i = scanner.nextInt();
            if(i==1){
                Socket socket = new Socket(InetAddress.getByName("10.36.140.123"),7777);
                wirteMessage(socket,null,null);
                getMessage(socket);
                socket.close();
            }
            else if(i==2){
                scanner = new Scanner(System.in);
                System.out.println("请输入要发送消息的用户ip");
                String targetIp = scanner.next();
                System.out.println("请输入发送的消息");
                String body = scanner.next();
                Socket socket2 = new Socket(InetAddress.getByName("10.36.140.123"),7777);
                wirteMessage(socket2, targetIp, body);
            }else System.out.println("请重新输入");
//        getMessage(socket2);
        }
    }

    private static void wirteMessage(Socket socket, String targetIp, String body) throws IOException {
        OutputStream outputStream = socket.getOutputStream();
        if(targetIp!=null&&body!=null)
            outputStream.write((targetIp+":"+body).getBytes());
        else outputStream.write(("null").getBytes());
        outputStream.flush();
    }

    private static void getMessage(Socket socket) throws IOException {
        InputStream inputStream = socket.getInputStream();
        byte[] bytes = new byte[1024];
        String s = new String(Arrays.copyOf(bytes,inputStream.read(bytes)));
        System.out.println(s+"end");
    }
}
//tcp模拟聊天软件功能
public class Service{
    public static void main(String[] args) throws Exception{
        ServerSocket serverSocket = new ServerSocket(7777);
        ArrayList<Message> messages = new ArrayList<>();
        while (true){
            System.out.println("等待客户端连接");
            Socket socket = serverSocket.accept();
            String ip = socket.getInetAddress().getHostAddress();
            System.out.println("访问的ip为"+ip);

            InputStream inputStream = socket.getInputStream();
//            BufferedInputStream bufferedInputStream = new BufferedInputStream(socket.getInputStream());
            byte[] bytes = new byte[1024];
            int len = inputStream.read(bytes);
//            System.out.println("111 "+len);
//            len = bufferedInputStream.read(bytes);
//            System.out.println("222"+len);
            socket.shutdownOutput();
            String s = new String(Arrays.copyOf(bytes,len));
            System.out.println(s);
            String[] split = s.split(":");
            if(split.length!=2){
                OutputStream outputStream = socket.getOutputStream();
                boolean flag = true;
                for (int i=0;i<messages.size();i++) {
                    if(messages.get(i).targetIp.equals(ip)){
                        outputStream.write((messages.get(i).ip+"新消息\n"+messages.get(i).body).getBytes());
                        messages.remove(i);
                        flag = false;
                        break;
                    }
                }
                if(flag){
                    outputStream.write("没有新消息".getBytes());
                }
                outputStream.flush();
            }
            else messages.add(new Message(socket.getInetAddress().getHostAddress(),split[0],split[1]));
            System.out.println(messages);
        }
    }
    static class Message{
        String ip;
        String targetIp;
        String body;

        public Message(String ip, String targetIp, String body) {
            this.ip = ip;
            this.targetIp = targetIp;
            this.body = body;
        }

        public Message() {
        }

        @Override
        public String toString() {
            return "Message{" +
                    "ip='" + ip + '\'' +
                    ", targetIp='" + targetIp + '\'' +
                    ", body='" + body + '\'' +
                    '}';
        }
    }
}

2. udp

public class Client {
    public static void main(String[] args) throws Exception{
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入接受方的Ip");
        String next = scanner.next();
        System.out.println("请输入发送的内容");
        String body = scanner.next();
        sendMessage(next,6666,body);
    }

    private static void sendMessage(String next, int port, String body) throws Exception{
        DatagramSocket socket = new DatagramSocket();
        DatagramPacket packet = new DatagramPacket(body.getBytes(), body.length(), InetAddress.getByName(next), port);
        socket.send(packet);
    }
}
public class Service {
    public static void main(String[] args) throws Exception{
        Message message = readPacket();
        System.out.println(message);
    }

    private static Message readPacket() throws IOException {
        DatagramSocket socket = new DatagramSocket(6666);
        byte[] bytes = new byte[1024];
        DatagramPacket packet = new DatagramPacket(bytes, bytes.length);
        socket.receive(packet);
        String s = new String(packet.getData());
        System.out.println(s);
        Message message = new Message();
        message.ip = packet.getAddress().getHostAddress();
        //规定数据格式为"ip=127.0.0.1&message=djfjkj"
        System.out.println(message);
        String[] split = s.split("=|&");
        for (int i = 0; i < split.length; i++) {
            if("ip".equals(split[i])){
                message.targetIp = split[i+++1];
            }else if("message".equals(split[i])){
                message.body = split[i++ +1];
            }
        }
        return message;
    }

    static class Message{
        String ip;
        String targetIp;
        String body;

        public Message(String ip, String targetIp, String body) {
            this.ip = ip;
            this.targetIp = targetIp;
            this.body = body;
        }

        public Message() {
        }

        @Override
        public String toString() {
            return "Message{" +
                    "ip='" + ip + '\'' +
                    ", targetIp='" + targetIp + '\'' +
                    ", body='" + body + '\'' +
                    '}';
        }
    }
}