区块链中的消息传播离不p2p通信 

java实现一个简单的p2p通信demo

工具：   idea   jdk1.8   maven

1  ：  idea新建maven项目，导入p2p所需要的jar包

    <dependency>
      <groupId>org.java-websocket</groupId>
      <artifactId>Java-WebSocket</artifactId>
      <version>1.3.4</version>

2   :   编写client

import org.java_websocket.WebSocket;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by jack on 2018/4/1.
 */
public class Client {


    private List<WebSocket> sockets = new ArrayList<WebSocket>();

    public List<WebSocket> getSockets() {
        return sockets;
    }

    public void connectToPeer(String peer) {
        try {
            final WebSocketClient socketClient = new WebSocketClient(new URI(peer)) {
                @Override
                public void onOpen(ServerHandshake serverHandshake) {
                    write(this, "客户端连接成功");
                    sockets.add(this);
                }

                @Override
                public void onMessage(String msg) {
                    System.out.println("收到服务端发送的消息:" + msg);
                }

                @Override
                public void onClose(int i, String msg, boolean b) {
                    System.out.println("connection failed");
                    sockets.remove(this);
                }

                @Override
                public void onError(Exception e) {
                    System.out.println("connection failed");
                    sockets.remove(this);
                }
            };
            socketClient.connect();
        } catch (URISyntaxException e) {
            System.out.println("p2p connect is error:" + e.getMessage());
        }
    }

    public void write(WebSocket ws, String message) {
        System.out.println("发送给" + ws.getRemoteSocketAddress().getPort() + "的p2p消息:" + message);
        ws.send(message);
    }

    public void broatcast(String message) {
        if (sockets.size() == 0) {
            return;
        }
        System.out.println("======广播消息开始：");
        for (WebSocket socket : sockets) {
            this.write(socket, message);
        }
        System.out.println("======广播消息结束");
    }
}

3  : 编写server

import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by jack on 2018/4/1.
 */
public class Server {



    private List<WebSocket> sockets = new ArrayList<WebSocket>();

    public List<WebSocket> getSockets() {
        return sockets;
    }

    public void initP2PServer(int port) {
        final WebSocketServer socketServer = new WebSocketServer(new InetSocketAddress(port)) {
            public void onOpen(WebSocket webSocket, ClientHandshake clientHandshake) {
                write(webSocket, "服务端连接成功");
                sockets.add(webSocket);
            }

            public void onClose(WebSocket webSocket, int i, String s, boolean b) {
                System.out.println("connection failed to peer:" + webSocket.getRemoteSocketAddress());
                sockets.remove(webSocket);
            }

            public void onMessage(WebSocket webSocket, String msg) {
                System.out.println("接收到客户端消息：" + msg);
                write(webSocket, "服务器收到消息");
                //broatcast("服务器收到消息:" + msg);
            }

            public void onError(WebSocket webSocket, Exception e) {
                System.out.println("connection failed to peer:" + webSocket.getRemoteSocketAddress());
                sockets.remove(webSocket);
            }

            public void onStart() {

            }
        };
        socketServer.start();
        System.out.println("listening websocket p2p port on: " + port);
    }

    public void write(WebSocket ws, String message) {
        System.out.println("发送给" + ws.getRemoteSocketAddress().getPort() + "的p2p消息:" + message);
        ws.send(message);
    }

    public void broatcast(String message) {
        if (sockets.size() == 0) {
            return;
        }
        System.out.println("======广播消息开始：");
        for (WebSocket socket : sockets) {
            this.write(socket, message);
        }
        System.out.println("======广播消息结束");
    }
}

4  ： 编写main测试主入口

/**
 * Created by jack on 2018/4/1.
 */
public class Main {

    public static void main(String[] args) {
        Server p2pServer = new Server();
        Client p2pClient = new Client();
        int p2pPort = Integer.valueOf(args[0]);
        // 启动p2p服务端
        p2pServer.initP2PServer(p2pPort);
        if (args.length == 2 && args[1] != null) {
            // 作为p2p客户端连接p2p服务端
            p2pClient.connectToPeer(args[1]);
        }
    }
}

5： 进行配置

单机 main 方法  ---选择  run ----选择  eidt conFigurations----左上角"+"号-----选择application  

6  ： 进行测试

          先执行main  当作第一个服务器，  再执行main2 ，当作第二个服务器

得到结果如下