这篇文章给大家分享的是有关Java怎么实现NIO聊天室的内容。小编觉得挺实用的，因此分享给大家做个参考，一起跟随小编过来看看吧。
功能介绍
功能:群聊+私发+上线提醒+下线提醒+查询在线用户
文件
Utils
需要用maven导入下面两个包
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.18</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> </dependency>package moremorechat_nio;import lombok.extern.slf4j.Slf4j;import java.io.*;@Slf4jpublic class Utils { public static Message decode(byte[] buf) throws IOException, ClassNotFoundException { ByteArrayInputStream bais = new ByteArrayInputStream(buf); ObjectInputStream ois = new ObjectInputStream(bais); return (Message) ois.readObject(); } public static byte[] encode(Message message) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(baos); oos.writeObject(message); oos.flush(); return baos.toByteArray(); }}FinalValue
package moremorechat_nio;public final class FinalValue { public static final int MSG_SYSTEM = 0; public static final int MSG_GROUP = 1; public static final int MSG_PRIVATE = 2; public static final int MSG_ONLINE = 3; public static final int MSG_NAME = 4;}Message
package moremorechat_nio;import java.io.Serializable;public class Message implements Serializable { public int type; public String message; public Message() { } public Message(String message) { this.message = message; } public Message(int type, String message) { this.type = type; this.message = message; } @Override public String toString() { return "Message{" + "type=" + type + ", message='" + message + '\'' + '}'; }}NioServer
package moremorechat_nio;import lombok.extern.slf4j.Slf4j;import java.io.*;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.*;import java.util.ArrayList;import java.util.Iterator;import java.util.Set;import java.util.concurrent.atomic.AtomicBoolean;import java.util.stream.Collectors;import static moremorechat_nio.FinalValue.*;@Slf4jpublic class NioServer { private Selector selector; private ServerSocketChannel ssc; public NioServer() { try { // 创建 selector, 管理多个 channel selector = Selector.open(); //打开ServerSocketChannel，用于监听客户端的连接，它是所有客户端连接的父通道 ssc = ServerSocketChannel.open(); ssc.bind(new InetSocketAddress(8888)); //设置连接为非堵塞模式 ssc.configureBlocking(false); // 2. 建立 selector 和 channel 的联系（注册） // SelectionKey 就是将来事件发生后，通过它可以知道事件和哪个channel的事件 //将ServerSocketChannel注册到Reactor线程的多路复用器Selector上，监听ACCEPT事件 ssc.register(selector, SelectionKey.OP_ACCEPT); } catch (IOException e) { e.printStackTrace(); } } public static void main(String[] args) { NioServer server = new NioServer(); log.debug("server启动完成，等待用户连接..."); try { server.listen(); } catch (Exception e) { log.debug("发生了一些问题"); } } private void listen() throws Exception { while (true) { // select 方法, 没有事件发生，线程阻塞，有事件，线程才会恢复运行, 通过Selector的select（）方法可以选择已经准备就绪的通道 （这些通道包含你感兴趣的的事件） //通过Selector的select（）方法可以选择已经准备就绪的通道 （这些通道包含你感兴趣的的事件） // select 在事件未处理时，它不会阻塞, 事件发生后要么处理，要么取消，不能置之不理 selector.select(); // 处理事件, selectedKeys 内部包含了所有发生的事件 Iterator<SelectionKey> iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { SelectionKey key = iterator.next(); // 处理key 时，要从 selectedKeys 集合中删除，否则下次处理就会有问题 iterator.remove(); // 区分事件类型 if (key.isAcceptable()) { ServerSocketChannel channel = (ServerSocketChannel) key.channel(); SocketChannel sc = channel.accept(); sc.configureBlocking(false); sc.register(selector, SelectionKey.OP_READ); } else if (key.isReadable()) { dealReadEvent(key); } } } } private void dealReadEvent(SelectionKey key) { SocketChannel channel = null; try { channel = (SocketChannel) key.channel(); ByteBuffer buffer = ByteBuffer.allocate(1024); int read = channel.read(buffer); // 如果是正常断开，read 的方法的返回值是 -1 if (read == -1) { //cancel 会取消注册在 selector 上的 channel，并从 keys 集合中删除 key 后续不会再监听事件 key.cancel(); } else { buffer.flip(); Message msg = Utils.decode(buffer.array()); log.debug(msg.toString()); dealMessage(msg, key, channel); } } catch (IOException | ClassNotFoundException e) { System.out.println((key.attachment() == null ? "匿名用户" : key.attachment()) + " 离线了.."); dealMessage(new Message(MSG_SYSTEM, key.attachment() + " 离线了.."), key, channel); //取消注册 key.cancel(); //关闭通道 try { channel.close(); } catch (IOException ioException) { ioException.printStackTrace(); } } } private void dealMessage(Message msg, SelectionKey key, SocketChannel channel) { switch (msg.type) { case MSG_NAME: key.attach(msg.message); log.debug("用户{}已上线", msg.message); getConnectedChannel(channel).forEach(selectionKey -> { SocketChannel sc = (SocketChannel) selectionKey.channel(); sendMsgToClient(new Message("收到一条系统消息: " + msg.message + "已上线"), sc); }); break; case MSG_GROUP: getConnectedChannel(channel).forEach(selectionKey -> { SocketChannel sc = (SocketChannel) selectionKey.channel(); sendMsgToClient(new Message(key.attachment() + "给大家发送了一条消息: " + msg.message), sc); }); break; case MSG_PRIVATE: String[] s = msg.message.split("_"); AtomicBoolean flag = new AtomicBoolean(false); getConnectedChannel(channel).stream().filter(sk -> s[0].equals(sk.attachment())).forEach(selectionKey -> { SocketChannel sc = (SocketChannel) selectionKey.channel(); sendMsgToClient(new Message(key.attachment() + "给你发送了一条消息: " + s[1]), sc); flag.set(true); }); if (!flag.get()){ sendMsgToClient(new Message(s[1]+"用户不存在,请重新输入！！！"), channel); } break; case MSG_ONLINE: ArrayList<String> onlineList = new ArrayList<>(); onlineList.add((String) key.attachment()); getConnectedChannel(channel).forEach(selectionKey -> onlineList.add((String) selectionKey.attachment())); sendMsgToClient(new Message(onlineList.toString()), channel); break; case MSG_SYSTEM: getConnectedChannel(channel).forEach(selectionKey -> { SocketChannel sc = (SocketChannel) selectionKey.channel(); sendMsgToClient(new Message("收到一条系统消息: " + msg.message), sc); }); break; default: break; } } private void sendMsgToClient(Message msg, SocketChannel sc) { try { byte[] bytes = Utils.encode(msg); sc.write(ByteBuffer.wrap(bytes)); } catch (IOException e) { log.debug("sendMsgToClient出现了一些问题"); } } private Set<SelectionKey> getConnectedChannel(SocketChannel channel) { return selector.keys().stream() .filter(item -> item.channel() instanceof SocketChannel && item.channel().isOpen() && item.channel() != channel) .collect(Collectors.toSet()); }}NioClient
package moremorechat_nio;import lombok.extern.slf4j.Slf4j;import java.io.*;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;import static moremorechat_nio.FinalValue.*;@Slf4jpublic class NioClient { private Selector selector; private SocketChannel socketChannel; private String username; private static Scanner input; public NioClient() throws IOException { selector = Selector.open(); socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 8888)); socketChannel.configureBlocking(false); socketChannel.register(selector, SelectionKey.OP_READ); log.debug("client启动完成......"); log.debug("请输入你的名字完成注册"); input = new Scanner(System.in); username = input.next(); log.debug("欢迎{}来到聊天系统", username); } public static void main(String[] args) throws IOException { System.out.println("tips: \n1. 直接发送消息会发给当前的所有用户 \n2. @用户名:消息 会私发给你要发送的用户 \n3. 输入 查询在线用户 会显示当前的在线用户"); NioClient client = new NioClient(); //启动一个子线程接受服务器发送过来的消息 new Thread(() -> { try { client.acceptMessageFromServer(); } catch (Exception e) { e.printStackTrace(); } }, "receiveClientThread").start(); //调用sendMessageToServer,发送消息到服务端 client.sendMessageToServer(); } private void sendMessageToServer() throws IOException { //先把用户名发给客户端 Message message = new Message(MSG_NAME, username); byte[] bytes = Utils.encode(message); socketChannel.write(ByteBuffer.wrap(bytes)); while (input.hasNextLine()) { String msgStr = input.next(); Message msg; boolean isPrivate = msgStr.startsWith("@"); if (isPrivate) { int idx = msgStr.indexOf(":"); String targetName = msgStr.substring(1, idx); msgStr = msgStr.substring(idx + 1); msg = new Message(MSG_PRIVATE, targetName + "_" + msgStr); } else if ("查询在线用户".equals(msgStr)) { msg = new Message(MSG_ONLINE, "请求在线人数"); } else { msg = new Message(MSG_GROUP, msgStr); } byte[] bytes1 = Utils.encode(msg); socketChannel.write(ByteBuffer.wrap(bytes1)); } } private void acceptMessageFromServer() throws Exception { while (selector.select() > 0) { Iterator<SelectionKey> iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { SelectionKey key = iterator.next(); iterator.remove(); if (key.isReadable()) { SocketChannel sc = (SocketChannel) key.channel(); ByteBuffer buffer = ByteBuffer.allocate(1024); sc.read(buffer); Message message = Utils.decode(buffer.array()); log.debug(String.valueOf(message.message)); } } } }}java基本数据类型有哪些
Java的基本数据类型分为：1、整数类型，用来表示整数的数据类型。2、浮点类型，用来表示小数的数据类型。3、字符类型，字符类型的关键字是“char”。4、布尔类型，是表示逻辑值的基本数据类型。
感谢各位的阅读！关于“Java怎么实现NIO聊天室”这篇文章就分享到这里了，希望以上内容可以对大家有一定的帮助，让大家可以学到更多知识，如果觉得文章不错，可以把它分享出去让更多的人看到吧！
