Java?NIO怎么實(shí)現(xiàn)聊天室功能

這篇文章主要介紹了Java NIO怎么實(shí)現(xiàn)聊天室功能，具有一定借鑒價(jià)值，感興趣的朋友可以參考下，希望大家閱讀完這篇文章之后大有收獲，下面讓小編帶著大家一起了解一下。

具體內(nèi)容如下

代碼里面已經(jīng)包含了必要的注釋，這里不詳述了。實(shí)現(xiàn)了基本的聊天室功能。

常量類：

public class Constant {
    public static final int serverPort = 44444;
}

服務(wù)端：

package server;
 
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;
 
import constant.Constant;
 
public class SocketServer {
    private Charset charset = Charset.forName("UTF-8");
    private ServerSocketChannel serverSocketChannel;
    private Selector serverSocketSelector;
    private SelectionKey serverRegisterKey;
    private ByteBuffer buffer = ByteBuffer.allocate(1024);
 
    public static void main(String[] args) throws IOException {
        new SocketServer().openServer(new InetSocketAddress(Constant.serverPort));
    }
 
    public void openServer(SocketAddress address) throws IOException {
        init(address);
        handle();
    }
 
    private void init(SocketAddress address) throws IOException {
        serverSocketSelector = Selector.open();
 
        serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.configureBlocking(false);
        serverRegisterKey = serverSocketChannel.register(serverSocketSelector, SelectionKey.OP_ACCEPT);
 
        serverSocketChannel.socket().bind(address);
    }
 
    private void handle() throws IOException {
        System.out.println("服務(wù)端open");
        while (serverSocketSelector.select() > 0) {
            Iterator<SelectionKey> iterator = serverSocketSelector.selectedKeys().iterator();
 
            // 為什么這里要用迭代器，而不用增強(qiáng)for循環(huán)之類的呢？是因?yàn)檫@里獲得一個(gè)key之后，要對(duì)其進(jìn)行移除，避免二次處理，造成影響
            while (iterator.hasNext()) {
                dispatch(iterator.next());
                iterator.remove();
            }
        }
    }
 
    private void dispatch(SelectionKey key) throws IOException {
        if (key.isAcceptable()) {
            accept(key);
        } else if (key.isReadable()) {
            readMessage(key);
        } else if (key.isValid() && key.isWritable()) {
            writeMessage(key);
        }
    }
 
    private void accept(SelectionKey key) throws IOException, ClosedChannelException {
        // 主要的是，接收事件是發(fā)生在服務(wù)器這邊的，所以這邊的通道要強(qiáng)轉(zhuǎn)為ServerSocketChannel
        ServerSocketChannel server = (ServerSocketChannel) key.channel();
        SocketChannel client = server.accept();
        client.configureBlocking(false);
        // 同時(shí)再給該通道注冊(cè)選擇器，監(jiān)聽的內(nèi)容的讀取
        client.register(serverSocketSelector, SelectionKey.OP_READ);
    }
 
    private void readMessage(SelectionKey key) throws IOException {
        SocketChannel client = (SocketChannel) key.channel();
        client.read(buffer);
        // 調(diào)整為讀取模式
        buffer.flip();
        String content = charset.decode(buffer).toString();
        // 壓縮空間，即拋棄已經(jīng)讀取的內(nèi)容（實(shí)際上還在里面，只是處于等待被覆蓋狀態(tài)）
        buffer.compact();
        // 這里可以根據(jù)業(yè)務(wù)邏輯，設(shè)置不設(shè)置都可以，但是這里想接受到消息后立馬回復(fù)一條消息，所以設(shè)置下一次感興趣的（監(jiān)聽）事件為寫
        key.interestOps(SelectionKey.OP_WRITE);
        // 設(shè)置系統(tǒng)回復(fù)信息
        key.attach("系統(tǒng)已經(jīng)收到你的消息\n");
        // 開始廣播這個(gè)客戶端的內(nèi)容到其他客戶端
        broadcast(key, content);
    }
 
    private void broadcast(SelectionKey self, String content) throws IOException {
        Set<SelectionKey> selectedKeys = self.selector().keys();
        for (SelectionKey key : selectedKeys) {
 
            // 不能發(fā)送給自己,也不要服務(wù)器自己本身對(duì)這個(gè)有反應(yīng)
            if (key != self && key != serverRegisterKey) {
                String oldMessage = (String) key.attach(null);
                // 如果有舊消息的話，在下一次發(fā)送時(shí)，連同舊消息一起發(fā)送
                key.attach(oldMessage != null ? oldMessage + content : content);
                key.interestOps(key.interestOps() | SelectionKey.OP_WRITE);
            }
        }
    }
 
    private void writeMessage(SelectionKey key) throws IOException {
        SocketChannel client = (SocketChannel) key.channel();
        // 獲取發(fā)給這個(gè)客戶端的消息，并清空消息
        client.write(charset.encode((String) key.attach(null)));
        key.interestOps(SelectionKey.OP_READ);
    }
}

客戶端（包含了Socket版本和SocketChannel版本）：

package client;
 
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Scanner;
 
import constant.Constant;
 
public class SocketClient {
 
    public static void main(String[] args) throws IOException {
        nioVersion();
        // ioVersion();
    }
 
    private static void ioVersion() throws UnknownHostException, IOException {
        System.out.println("客戶端");
        final Socket socket = new Socket();
        socket.connect(new InetSocketAddress(Constant.serverPort));
 
        new Thread() {
            @Override
            public void run() {
                Scanner scanner = new Scanner(System.in);
 
                while (scanner.hasNext()) {
                    String line = scanner.nextLine();
                    try {
                        socket.getOutputStream().write((line + "\n").getBytes("UTF-8"));
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                scanner.close();
                try {
                    socket.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            };
        }.start();
 
        new Thread() {
            @Override
            public void run() {
                try {
                    Scanner scanner = new Scanner(socket.getInputStream(), "utf-8");
                    while (scanner.hasNext()) {
                        String line = scanner.nextLine();
                        System.out.println("收到消息：" + line);
                    }
                    scanner.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
 
            }
        }.start();
    }
 
    private static void nioVersion() throws IOException {
        Charset charset = Charset.forName("UTF-8");
 
        System.out.println("客戶端");
        SocketChannel socketChannel = SocketChannel.open();
        // 設(shè)置為非阻塞模式
        socketChannel.configureBlocking(false);
        socketChannel.connect(new InetSocketAddress(Constant.serverPort));
 
        while (true) {
            if (socketChannel.finishConnect()) {
                new Thread() {
                    @Override
                    public void run() {
                        Scanner scanner = new Scanner(System.in);
                        while (scanner.hasNext()) {
                            String input = scanner.nextLine();
 
                            try {
                                socketChannel.write(charset.encode(input));
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
 
                        }
                        scanner.close();
                    }
                }.start();
 
                new Thread() {
                    ByteBuffer dst = ByteBuffer.allocate(1024);
 
                    @Override
                    public void run() {
                        while (true) {
                            try {
                                int len = socketChannel.read(dst);
                                if (len > 0) {
                                    dst.flip();
                                    System.out.println("收到消息：" + charset.decode(dst));
                                    dst.compact();
                                }
                            } catch (IOException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                        }
                    }
                }.start();
                return;
            }
        }
    }
 
}

感謝你能夠認(rèn)真閱讀完這篇文章，希望小編分享的“Java NIO怎么實(shí)現(xiàn)聊天室功能”這篇文章對(duì)大家有幫助，同時(shí)也希望大家多多支持億速云，關(guān)注億速云行業(yè)資訊頻道，更多相關(guān)知識(shí)等著你來學(xué)習(xí)!