Java群聊系统
Java硬件工程师 人气:0实例要求:
1.编写一个 NIO 群聊系统,实现服务器端和客户端之间的数据简单通讯(非阻塞)
2.实现多人群聊
3.服务器端:可以监测用户上线,离线,并实现消息转发功能
4.客户端:通过 Channel 可以无阻塞发送消息给其它所有用户,同时可以接受其它用户发送的消息(有服务器转发得到)
5.目的:进一步理解 NIO 非阻塞网络编程机制
6.示意图分析和代码
// 服务端:
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 { //定义属性 private Selector selector; private ServerSocketChannel listenChannel; private static final int PORT = 6667; //构造器 //初始化工作 public GroupChatServer() { try { //得到选择器 selector = Selector.open(); //ServerSocketChannel listenChannel = ServerSocketChannel.open(); //绑定端口 listenChannel.socket().bind(new InetSocketAddress(PORT)); //设置非阻塞模式 listenChannel.configureBlocking(false); //将该 listenChannel 注册到 selector listenChannel.register(selector, SelectionKey.OP_ACCEPT); } catch (IOException e) { e.printStackTrace(); } } public void listen() { try { //循环处理 while (true) { int count = selector.select(); if (count > 0) { //有事件处理 // 遍历得到 selectionKey 集合 Iterator<SelectionKey> iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { //取出 selectionkey SelectionKey key = iterator.next(); //监听到 accept if (key.isAcceptable()) { SocketChannel sc = listenChannel.accept(); sc.configureBlocking(false); //将该 sc 注册到 seletor sc.register(selector, SelectionKey.OP_READ); //提示 System.out.println(sc.getRemoteAddress() + " 上线 "); } if (key.isReadable()) {//通道发送read事件,即通道是可读的状态 // 处理读(专门写方法..) readData(key); } //当前的 key 删除,防止重复处理 iterator.remove(); } } else { System.out.println("等待...."); } } } catch (Exception e) { e.printStackTrace(); } finally { //发生异常处理.... } } //读取客户端消息 public void readData(SelectionKey key) { SocketChannel channel = null; try { //得到 channel channel = (SocketChannel) key.channel(); //创建 buffer ByteBuffer buffer = ByteBuffer.allocate(1024); int count = channel.read(buffer); //根据 count 的值做处理 if (count > 0) { //把缓存区的数据转成字符串 String msg = new String(buffer.array()); //输出该消息 System.out.println("form客户端:" + msg); //向其它的客户端转发消息(去掉自己),专门写一个方法来处理 sendInfoToOtherClients(msg, channel); } } catch (IOException e) { try { System.out.println(channel.getRemoteAddress() + "离线了.."); //取消注册 key.cancel(); //关闭通道 channel.close(); } catch (IOException e2) { e2.printStackTrace(); } } } //转发消息给其它客户(通道) private void sendInfoToOtherClients(String msg, SocketChannel self) throws IOException { System.out.println("服务器转发消息中..."); //遍历所有注册到 selector 上的 SocketChannel,并排除 self for (SelectionKey key : selector.keys()) { //通过 key 取出对应的 SocketChannel Channel targetChannel = key.channel(); //排除自己 if (targetChannel instanceof SocketChannel && targetChannel != self) { //转型 SocketChannel dest = (SocketChannel) targetChannel; //将 msg 存储到 buffer ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes()); //将 buffer 的数据写入通道 dest.write(buffer); } } } public static void main(String[] args) { //创建服务器对象 GroupChatServer groupChatServer = new GroupChatServer(); groupChatServer.listen(); } }
// 客户端:
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 { //定义相关的属性 private final String HOST = "127.0.0.1";//服务器的ip private final int PORT = 6667;//服务器端口 private Selector selector; private SocketChannel socketChannel; private String username; //构造器,完成初始化工作 public GroupChatClient() throws IOException { selector = Selector.open(); //连接服务器 socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT)); //设置非阻塞 socketChannel.configureBlocking(false); //将 channel 注册到selector socketChannel.register(selector, SelectionKey.OP_READ); //得到 username username = socketChannel.getLocalAddress().toString().substring(1); System.out.println(username + " is ok..."); } //向服务器发送消息 public void sendInfo(String info) { info = username + " 说:" + info; try { socketChannel.write(ByteBuffer.wrap(info.getBytes())); } catch (IOException e) { e.printStackTrace(); } } //读取从服务器端回复的消息 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()) { //得到相关的通道 SocketChannel sc = (SocketChannel) key.channel(); //得到一个 Buffer ByteBuffer buffer = ByteBuffer.allocate(1024); //读取 sc.read(buffer); //把读到的缓冲区的数据转成字符串 String msg = new String(buffer.array()); System.out.println(msg.trim()); } } iterator.remove(); //删除当前的 selectionKey,防止重复操作 } else { //System.out.println("没有可以用的通道..."); } } catch (Exception e) { e.printStackTrace(); } } 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); } } }
运行结果
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