java实现p2p聊天通信

以下是Java实现P2P聊天通信的步骤：

1. 创建一个服务器，用于客户端之间的通信。服务器需要监听客户端的连接请求，并将客户端的信息存储在一个列表中。

2. 创建一个客户端，用于与其他客户端进行通信。客户端需要向服务器注册自己的信息，包括唯一主键、IP地址和端口号。

3. 当客户端想要与其他客户端进行通信时，它需要向服务器查询目标客户端的信息，包括IP地址和端口号。

4. 客户端通过目标客户端的IP地址和端口号连接到目标客户端，建立通信连接。

5. 一旦连接建立成功，客户端之间就可以通过套接字进行通信，发送和接收消息、图片、音频和视频等文件。

以下是Java实现P2P聊天通信的代码示例：

1. 服务器代码

import java.io.*;
import java.net.*;
import java.util.*;

public class Server {
    private static List<ClientInfo> clients = new ArrayList<ClientInfo>();

    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(8888);
            System.out.println("Server started.");

            while (true) {
                Socket socket = serverSocket.accept();
                System.out.println("New client connected: " + socket.getInetAddress().getHostAddress());

                ClientInfo clientInfo = new ClientInfo(socket);
                clients.add(clientInfo);

                Thread thread = new Thread(new ServerHandler(clientInfo, clients));
                thread.start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class ServerHandler implements Runnable {
    private ClientInfo clientInfo;
    private List<ClientInfo> clients;

    public ServerHandler(ClientInfo clientInfo, List<ClientInfo> clients) {
        this.clientInfo = clientInfo;
        this.clients = clients;
    }

    public void run() {
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(clientInfo.getSocket().getInputStream()));

            while (true) {
                String message = reader.readLine();
                System.out.println("Received message from " + clientInfo.getId() + ": " + message);

                if (message.startsWith("REGISTER")) {
                    String[] parts = message.split(" ");
                    clientInfo.setId(parts[1]);
                    clientInfo.setIp(clientInfo.getSocket().getInetAddress().getHostAddress());
                    clientInfo.setPort(Integer.parseInt(parts[2]));
                    System.out.println("Registered client " + clientInfo.getId() + " at " + clientInfo.getIp() + ":" + clientInfo.getPort());
                } else if (message.startsWith("QUERY")) {
                    String[] parts = message.split(" ");
                    String targetId = parts[1];
                    ClientInfo targetClient = null;

                    for (ClientInfo client : clients) {
                        if (client.getId().equals(targetId)) {
                            targetClient = client;
                            break;
                        }
                    }

                    if (targetClient != null) {
                        String response = "CONNECT " + targetClient.getIp() + " " + targetClient.getPort();
                        PrintWriter writer = new PrintWriter(clientInfo.getSocket().getOutputStream());
                        writer.println(response);
                        writer.flush();
                        System.out.println("Sent response to " + clientInfo.getId() + ": " + response);
                    } else {
                        String response = "ERROR Target client not found.";
                        PrintWriter writer = new PrintWriter(clientInfo.getSocket().getOutputStream());
                        writer.println(response);
                        writer.flush();
                        System.out.println("Sent response to " + clientInfo.getId() + ": " + response);
                    }
                } else {
                    // Forward message to target client
                    String[] parts = message.split(" ");
                    String targetId = parts[0];
                    ClientInfo targetClient = null;

                    for (ClientInfo client : clients) {
                        if (client.getId().equals(targetId)) {
                            targetClient = client;
                            break;
                        }
                    }

                    if (targetClient != null) {
                        PrintWriter writer = new PrintWriter(targetClient.getSocket().getOutputStream());
                        writer.println(message);
                        writer.flush();
                        System.out.println("Forwarded message from " + clientInfo.getId() + " to " + targetClient.getId() + ": " + message);
                    } else {
                        String response = "ERROR Target client not found.";
                        PrintWriter writer = new PrintWriter(clientInfo.getSocket().getOutputStream());
                        writer.println(response);
                        writer.flush();
                        System.out.println("Sent response to " + clientInfo.getId() + ": " + response);
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class ClientInfo {
    private String id;
    private String ip;
    private int port;
    private Socket socket;

    public ClientInfo(Socket socket) {
        this.socket = socket;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getIp() {
        return ip;
    }

    public void setIp(String ip) {
        this.ip = ip;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    public Socket getSocket() {
        return socket;
    }
}

2. 客户端代码

import java.io.*;
import java.net.*;

public class Client {
    private static String id;
    private static String ip;
    private static int port;

    public static void main(String[] args) {
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            System.out.print("Enter your ID: ");
            id = reader.readLine();

            Socket socket = new Socket("localhost", 8888);
            System.out.println("Connected to server.");

            PrintWriter writer = new PrintWriter(socket.getOutputStream());
            writer.println("REGISTER " + id + " 0");
            writer.flush();

            BufferedReader serverReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            String response = serverReader.readLine();
            System.out.println("Received response from server: " + response);

            if (response.startsWith("CONNECT")) {
                String[] parts = response.split(" ");
                ip = parts[1];
                port = Integer.parseInt(parts[2]);
                System.out.println("Connected to client " + id + " at " + ip + ":" + port);

                Thread thread = new Thread(new ClientHandler(socket));
                thread.start();

                while (true) {
                    String message = reader.readLine();
                    Socket targetSocket = new Socket(ip, port);
                    PrintWriter targetWriter = new PrintWriter(targetSocket.getOutputStream());
                    targetWriter.println(id + " " + message);
                    targetWriter.flush();
                    targetSocket.close();
                }
            } else {
                System.out.println("Failed to connect to client " + id);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

class ClientHandler implements Runnable {
    private Socket socket;

    public ClientHandler(Socket socket) {
        this.socket = socket;
    }

    public void run() {
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            while (true) {
                String message = reader.readLine();
                System.out.println("Received message: " + message);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}