Netty学习(3) 使用NIO实现群聊客户端和服务端

NIO编写的和客户端和服务端示例

服务端：

package com.nettyStudy.nio.groupChat;

import org.omg.Messaging.SyncScopeHelper;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.Iterator;

public class GroupChatServer {
    private Selector selector;
    private ServerSocketChannel serverSocketChannel;
    private static final int port = 5555;

    public GroupChatServer(){
        try{
            selector = Selector.open();
            serverSocketChannel = ServerSocketChannel.open();
            serverSocketChannel.configureBlocking(false);
            serverSocketChannel.socket().bind(new InetSocketAddress(port));
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

        }catch (Exception e){
            e.printStackTrace();
        }

    }

    private void listen(){
        try {
            while (true){
                int count = selector.select(2000);
                if(count >  0){
                    Iterator<SelectionKey> sks = selector.selectedKeys().iterator();
                    while (sks.hasNext()){
                        SelectionKey selectionKey = sks.next();
                        //监听到客户端accept事件，客户端连接上线
                        if (selectionKey.isAcceptable()){
                            SocketChannel socketChannel = serverSocketChannel.accept();
                            socketChannel.configureBlocking(false);
                            socketChannel.register(selector,SelectionKey.OP_READ);
                            System.out.println(socketChannel.getRemoteAddress() + " 上线");
                        }
                        //通道发送读事件，为可读状态，读取客户端数据
                        if(selectionKey.isReadable()){

                            readMsg(selectionKey);
                        }
                        sks.remove();
                    }
                }else {
                    //System.out.println("等待...");
                }

            }

        }catch (Exception e){
            e.printStackTrace();
        }
    }

    private void readMsg(SelectionKey selectionKey){
        SocketChannel socketChannel = null;
        try {
            socketChannel = (SocketChannel) selectionKey.channel();
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
            int read = socketChannel.read(byteBuffer);
            if(read > 0){
                String msg = new String(byteBuffer.array());
                System.out.println("收到客户端"+socketChannel.getRemoteAddress() + "消息："+msg);
                //向其他客户端转发消息
                redirectMsg(msg,socketChannel);
            }
        }catch (Exception e){
            //离线了，断开
            try {
                System.out.println("客户端"+socketChannel.getRemoteAddress() + "离线了");
                selectionKey.cancel();
                socketChannel.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

    private void redirectMsg(String msg,SocketChannel self) throws IOException {
        System.out.println("服务器转发消息：form:"+ self.getRemoteAddress() + ", msg:"+msg);
        for(SelectionKey key: selector.keys()){
            Channel targetChannel = key.channel();
            if(targetChannel instanceof SocketChannel && targetChannel != self){
                //发送消息到客户端
                ((SocketChannel) targetChannel).write(ByteBuffer.wrap(msg.getBytes()));
            }
        }
    }

    public static void main(String[] args) {
         new GroupChatServer().listen();
    }
}

客户端：

package com.nettyStudy.nio.groupChat;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;

public class GroupChatClient {
    public static void main(String[] args) throws Exception {

        //启动我们客户端
        GroupChatClient chatClient = new GroupChatClient();

        //启动一个线程, 每个3秒，读取从服务器发送数据
        new Thread() {
            public void run() {

                while (true) {
                    chatClient.readInfo();
                    try {
                        Thread.currentThread().sleep(3000);
                    }catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();

        //发送数据给服务器端
        Scanner scanner = new Scanner(System.in);

        while (scanner.hasNextLine()) {
            String s = scanner.nextLine();
            chatClient.sendInfo(s);
        }
    }


    private Selector selector;
    private SocketChannel socketChannel;
    private String userName;
    public GroupChatClient(){
        try {
            selector = Selector.open();
            socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1",5555));

            socketChannel.configureBlocking(false);
            socketChannel.register(selector,SelectionKey.OP_READ);
            userName = socketChannel.getLocalAddress().toString();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void sendInfo(String info){
        info = userName + " 说：" + info;
        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    private void readInfo(){
        try {

            int select = selector.select(1000);

            if(select > 0){

                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()){
                    SelectionKey selectionKey = iterator.next();
                    if(selectionKey.isReadable()){
                        SocketChannel channel = (SocketChannel) selectionKey.channel();
                        ByteBuffer byteBuffer  = ByteBuffer.allocate(1024);
                        channel.read(byteBuffer);
                        String msg = new String(byteBuffer.array());
                        System.out.println(msg.trim());
                    }
                }
                iterator.remove();
            }else{
                //System.out.println("客户端没有可以用的通道");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}