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這篇文章主要為大家展示了“Java基于NIO如何實(shí)現(xiàn)群聊系統(tǒng)”,內(nèi)容簡而易懂,條理清晰,希望能夠幫助大家解決疑惑,下面讓小編帶領(lǐng)大家一起研究并學(xué)習(xí)一下“Java基于NIO如何實(shí)現(xiàn)群聊系統(tǒng)”這篇文章吧。
具體內(nèi)容如下
實(shí)例要求:
1.編寫一個(gè) NIO 群聊系統(tǒng),實(shí)現(xiàn)服務(wù)器端和客戶端之間的數(shù)據(jù)簡單通訊(非阻塞)
2.實(shí)現(xiàn)多人群聊
3.服務(wù)器端:可以監(jiān)測用戶上線,離線,并實(shí)現(xiàn)消息轉(zhuǎn)發(fā)功能
4.客戶端:通過 Channel 可以無阻塞發(fā)送消息給其它所有用戶,同時(shí)可以接受其它用戶發(fā)送的消息(有服務(wù)器轉(zhuǎn)發(fā)得到)
5.目的:進(jìn)一步理解 NIO 非阻塞網(wǎng)絡(luò)編程機(jī)制
6.示意圖分析和代碼
// 服務(wù)端:
package com.atguigu.nio.groupchat; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.Channel; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.util.Iterator; public class GroupChatServer { //定義屬性 private Selector selector; private ServerSocketChannel listenChannel; private static final int PORT = 6667; //構(gòu)造器 //初始化工作 public GroupChatServer() { try { //得到選擇器 selector = Selector.open(); //ServerSocketChannel listenChannel = ServerSocketChannel.open(); //綁定端口 listenChannel.socket().bind(new InetSocketAddress(PORT)); //設(shè)置非阻塞模式 listenChannel.configureBlocking(false); //將該 listenChannel 注冊到 selector listenChannel.register(selector, SelectionKey.OP_ACCEPT); } catch (IOException e) { e.printStackTrace(); } } public void listen() { try { //循環(huán)處理 while (true) { int count = selector.select(); if (count > 0) { //有事件處理 // 遍歷得到 selectionKey 集合 Iterator<SelectionKey> iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { //取出 selectionkey SelectionKey key = iterator.next(); //監(jiān)聽到 accept if (key.isAcceptable()) { SocketChannel sc = listenChannel.accept(); sc.configureBlocking(false); //將該 sc 注冊到 seletor sc.register(selector, SelectionKey.OP_READ); //提示 System.out.println(sc.getRemoteAddress() + " 上線 "); } if (key.isReadable()) {//通道發(fā)送read事件,即通道是可讀的狀態(tài) // 處理讀(專門寫方法..) readData(key); } //當(dāng)前的 key 刪除,防止重復(fù)處理 iterator.remove(); } } else { System.out.println("等待...."); } } } catch (Exception e) { e.printStackTrace(); } finally { //發(fā)生異常處理.... } } //讀取客戶端消息 public void readData(SelectionKey key) { SocketChannel channel = null; try { //得到 channel channel = (SocketChannel) key.channel(); //創(chuàng)建 buffer ByteBuffer buffer = ByteBuffer.allocate(1024); int count = channel.read(buffer); //根據(jù) count 的值做處理 if (count > 0) { //把緩存區(qū)的數(shù)據(jù)轉(zhuǎn)成字符串 String msg = new String(buffer.array()); //輸出該消息 System.out.println("form客戶端:" + msg); //向其它的客戶端轉(zhuǎn)發(fā)消息(去掉自己),專門寫一個(gè)方法來處理 sendInfoToOtherClients(msg, channel); } } catch (IOException e) { try { System.out.println(channel.getRemoteAddress() + "離線了.."); //取消注冊 key.cancel(); //關(guān)閉通道 channel.close(); } catch (IOException e2) { e2.printStackTrace(); } } } //轉(zhuǎn)發(fā)消息給其它客戶(通道) private void sendInfoToOtherClients(String msg, SocketChannel self) throws IOException { System.out.println("服務(wù)器轉(zhuǎn)發(fā)消息中..."); //遍歷所有注冊到 selector 上的 SocketChannel,并排除 self for (SelectionKey key : selector.keys()) { //通過 key 取出對應(yīng)的 SocketChannel Channel targetChannel = key.channel(); //排除自己 if (targetChannel instanceof SocketChannel && targetChannel != self) { //轉(zhuǎn)型 SocketChannel dest = (SocketChannel) targetChannel; //將 msg 存儲到 buffer ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes()); //將 buffer 的數(shù)據(jù)寫入通道 dest.write(buffer); } } } public static void main(String[] args) { //創(chuàng)建服務(wù)器對象 GroupChatServer groupChatServer = new GroupChatServer(); groupChatServer.listen(); } }
// 客戶端:
package com.atguigu.nio.groupchat; ~~import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; 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 { //定義相關(guān)的屬性 private final String HOST = "127.0.0.1";//服務(wù)器的ip private final int PORT = 6667;//服務(wù)器端口 private Selector selector; private SocketChannel socketChannel; private String username; //構(gòu)造器,完成初始化工作 public GroupChatClient() throws IOException { selector = Selector.open(); //連接服務(wù)器 socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT)); //設(shè)置非阻塞 socketChannel.configureBlocking(false); //將 channel 注冊到selector socketChannel.register(selector, SelectionKey.OP_READ); //得到 username username = socketChannel.getLocalAddress().toString().substring(1); System.out.println(username + " is ok..."); } //向服務(wù)器發(fā)送消息 public void sendInfo(String info) { info = username + " 說:" + info; try { socketChannel.write(ByteBuffer.wrap(info.getBytes())); } catch (IOException e) { e.printStackTrace(); } } //讀取從服務(wù)器端回復(fù)的消息 public void readInfo() { try { int readChannels = selector.select(); if (readChannels > 0) {//有可以用的通道 Iterator<SelectionKey> iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { SelectionKey key = iterator.next(); if (key.isReadable()) { //得到相關(guān)的通道 SocketChannel sc = (SocketChannel) key.channel(); //得到一個(gè) Buffer ByteBuffer buffer = ByteBuffer.allocate(1024); //讀取 sc.read(buffer); //把讀到的緩沖區(qū)的數(shù)據(jù)轉(zhuǎn)成字符串 String msg = new String(buffer.array()); System.out.println(msg.trim()); } } iterator.remove(); //刪除當(dāng)前的 selectionKey,防止重復(fù)操作 } else { //System.out.println("沒有可以用的通道..."); } } catch (Exception e) { e.printStackTrace(); } } public static void main(String[] args) throws Exception { //啟動(dòng)我們客戶端 GroupChatClient chatClient = new GroupChatClient(); //啟動(dòng)一個(gè)線程,每個(gè) 3 秒,讀取從服務(wù)器發(fā)送數(shù)據(jù) new Thread() { public void run() { while (true) { chatClient.readInfo(); try { Thread.currentThread().sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } } } }.start(); //發(fā)送數(shù)據(jù)給服務(wù)器端 Scanner scanner = new Scanner(System.in); while (scanner.hasNextLine()) { String s = scanner.nextLine(); chatClient.sendInfo(s); } } }
運(yùn)行結(jié)果
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