NIO群聊系统

这里面的知识比较全面，用到了我们之前学习的三大组件，首先我先来给大家介绍本系统的功能

服务端功能

最基本的当然是注册功能，也就是将serverSocketChannel注册进Selector，Selector负责调度事件

监听、读取客户端发来的消息

收到客户端的信息后将其转发到其它客户端，完成群聊功能

客户端功能

连接服务端，注册进Selector

读写消息

以上就是群聊系统最基本的功能，我们直接上代码，每句话的含义我都标在它的顶上了

服务端源码

package com.hecl.designmodels.NIO.GroupChat;import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.Iterator;
import java.util.Set;public class GroupChatServer {//定义一个选择器对象private Selector selector;//定义一个ServerSocketChannel对象private ServerSocketChannel serverSocketChannel;//养成习惯，对于这种不变的属性我们使用static final 来定义，且单词为全大写private static final int PORT = 7000;public GroupChatServer() {try{//获取选择器selector = Selector.open();//获取ServerSocketChannelserverSocketChannel = ServerSocketChannel.open();//绑定端口serverSocketChannel.socket().bind(new InetSocketAddress(PORT));//设置为非阻塞serverSocketChannel.configureBlocking(false);//将serverSocketChannel注册进selectorserverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);}catch (Exception e){e.printStackTrace();}}//监听方法public void listen(){try{while(true){int count = selector.select();//如果count大于0就说明有事件发生if(count > 0){//selector.selectedKeys()获取一个Set<SelectionKey>集合//遍历SelectionKeyIterator<SelectionKey> iterator =  selector.selectedKeys().iterator();while (iterator.hasNext()){//获取目前遍历到的SelectionKey对象SelectionKey key = iterator.next();//有新连接创建if(key.isAcceptable()){//获取连接到服务器的SocketChannelSocketChannel socketChannel = serverSocketChannel.accept();//将该通道设置为非阻塞socketChannel.configureBlocking(false);//注册进selectorsocketChannel.register(selector,SelectionKey.OP_READ);System.out.println(socketChannel.getRemoteAddress() + ": 已登录");}//发生有数据发送过来触发读事件if(key.isReadable()){//调用读取数据的方法readMsg(key);}iterator.remove();}}}}catch (IOException e){e.printStackTrace();}}//读取数据方法public void readMsg(SelectionKey selectionKey){SocketChannel socketChannel = null;try {//通过key获取与之关联的SocketChannelsocketChannel = (SocketChannel) selectionKey.channel();//创建缓冲区去接收通道内的数据ByteBuffer byteBuffer = ByteBuffer.allocate(2048);//得到通道内的数据socketChannel.read(byteBuffer);//在控制台打印消息System.out.println("from " + socketChannel.getRemoteAddress() + "客户端 :" + new String(byteBuffer.array()));//转发消息sendMsgToOtherClients(new String(byteBuffer.array()),socketChannel);}catch (IOException e){try{System.out.println(socketChannel.getRemoteAddress() + "下线");//消毁selectionKeyselectionKey.cancel();//销毁socketChannelsocketChannel.close();}catch (Exception exception){exception.printStackTrace();}}}//向其他客户端转发消息，不包括自己public void sendMsgToOtherClients(String msg,SocketChannel socketChannel){try {//获取所有的SelectionKeyfor(SelectionKey OtherKey : selector.keys()){//获取对应的socketChannelChannel OtherChannel = OtherKey.channel();//排除自身if(OtherChannel instanceof SocketChannel && socketChannel != OtherChannel){//向下转型SocketChannel OtherSocketChannel = (SocketChannel) OtherChannel;//创建缓冲区ByteBuffer byteBuffer = ByteBuffer.wrap(msg.getBytes());//将缓冲区的数据写入通道OtherSocketChannel.write(byteBuffer);}}}catch (IOException e){e.printStackTrace();}}public static void main(String[] args) {//启动服务端GroupChatServer groupChatServer = new GroupChatServer();//调用监听方法groupChatServer.listen();}
}

客户端源码

package com.hecl.designmodels.NIO.GroupChat;import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;
import designModels.design_mode_07_BridgePattern.Pay;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;
import java.util.Set;public class GroupChatClient {//定义需要连接服务器的地址与端口号private static final String HOST = "127.0.0.1";private static final int PORT = 7000;//定义选择器对象private Selector selector;//定义SocketChannel对象private SocketChannel socketChannel;//登录名private String username;public GroupChatClient(String username){try {//获取一个SocketChannel对象，并连接服务器socketChannel = SocketChannel.open(new InetSocketAddress(HOST,PORT));//得到选择器selector = Selector.open();//设置非阻塞socketChannel.configureBlocking(false);//将通道注册进selectorsocketChannel.register(selector, SelectionKey.OP_READ);//得到登录名称this.username = username;String s = username + " 加入群聊";System.out.println(s);socketChannel.write(ByteBuffer.wrap(s.getBytes()));}catch (IOException e){e.printStackTrace();}}public void sendMsg(String msg){//数据拼接形成最终发送的消息String info = username + " say : " + msg;try{//将缓冲区内的数据写入通道socketChannel.write(ByteBuffer.wrap(info.getBytes()));System.out.println("I say : " + msg);}catch (IOException e){e.printStackTrace();}}//参照服务端读取数据代码public void readMsg(){try{int count = selector.select();if(count>0){Set<SelectionKey> selectionKeySet = selector.selectedKeys();Iterator<SelectionKey> iterator = selectionKeySet.iterator();while (iterator.hasNext()){SelectionKey selectionKey = iterator.next();if(selectionKey.isReadable()){SocketChannel socketChannel = (SocketChannel) selectionKey.channel();ByteBuffer byteBuffer = ByteBuffer.allocate(2048);socketChannel.read(byteBuffer);String msg = new String(byteBuffer.array());System.out.println(msg);}//必须要移除，要不然收不到其它客户端的消息iterator.remove();}}}catch (IOException e){e.printStackTrace();}}public static void main(String[] args) {Scanner scannerName = new Scanner(System.in);//启动服务GroupChatClient groupChatClient = new GroupChatClient(scannerName.nextLine());//新建一个线程循环调用读取数据的方法new Thread() {public void run(){while(true) {groupChatClient.readMsg();try {//休息2sThread.sleep(2000);}catch (Exception e){e.printStackTrace();}}}}.start();//获取输入消息Scanner scanner = new Scanner(System.in);while (scanner.hasNextLine()){//获取输入消息并调用sendMsg(String msg)groupChatClient.sendMsg(scanner.nextLine());}}}