Initial commit

NIOChatServ/.gitignore

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+### IntelliJ IDEA ###
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+bin/
+!**/src/main/**/bin/
+!**/src/test/**/bin/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

NIOChatServ/.idea/.gitignore

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+# 默认忽略的文件
+/shelf/
+/workspace.xml
+# 基于编辑器的 HTTP 客户端请求
+/httpRequests/
+# 依赖于环境的 Maven 主目录路径
+/mavenHomeManager.xml
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

NIOChatServ/.idea/misc.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

NIOChatServ/.idea/modules.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/NIOChatServ.iml" filepath="$PROJECT_DIR$/NIOChatServ.iml" />
+    </modules>
+  </component>
+</project>

NIOChatServ/.idea/vcs.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings" defaultProject="true" />
+</project>

NIOChatServ/NIOChatServ.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

NIOChatServ/src/client/NioChatClient.java

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+package client;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.*;
+import java.util.Iterator;
+
+public class NioChatClient extends JFrame {
+
+    // UI 组件
+    private JTextField hostField;
+    private JTextField portField;
+    private JButton connectButton;
+
+    private JTextArea messageArea;       // 显示聊天内容
+    private JTextField inputField;       // 输入框
+    private JButton sendButton;          // 发送按钮
+
+    // NIO相关
+    private volatile SocketChannel socketChannel;
+    private volatile Selector selector;
+    private volatile boolean running = false; // 用于控制读线程
+
+    private Thread readThread; // 后台读取服务器消息的线程
+
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(() -> {
+            NioChatClient client = new NioChatClient();
+            client.setVisible(true);
+        });
+    }
+
+    /**
+     * 构造UI
+     */
+    public NioChatClient() {
+        super("NIO Chat Client");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setSize(600, 400);
+
+        // 主机、端口输入区域
+        JPanel connectPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
+        connectPanel.add(new JLabel("服务器主机:"));
+        hostField = new JTextField("127.0.0.1", 10);
+        connectPanel.add(hostField);
+
+        connectPanel.add(new JLabel("端口:"));
+        portField = new JTextField("8888", 5);
+        connectPanel.add(portField);
+
+        connectButton = new JButton("连接");
+        connectPanel.add(connectButton);
+
+        // 聊天显示区域
+        messageArea = new JTextArea();
+        messageArea.setEditable(false);
+        JScrollPane scrollPane = new JScrollPane(messageArea);
+
+        // 发送消息区域
+        JPanel inputPanel = new JPanel(new BorderLayout());
+        inputField = new JTextField();
+        sendButton = new JButton("发送");
+
+        inputPanel.add(inputField, BorderLayout.CENTER);
+        inputPanel.add(sendButton, BorderLayout.EAST);
+
+        // 布局
+        getContentPane().setLayout(new BorderLayout());
+        getContentPane().add(connectPanel, BorderLayout.NORTH);
+        getContentPane().add(scrollPane, BorderLayout.CENTER);
+        getContentPane().add(inputPanel, BorderLayout.SOUTH);
+
+        // 按钮事件绑定
+        connectButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                if (!running) {
+                    connectToServer();
+                } else {
+                    disconnectFromServer();
+                }
+            }
+        });
+
+        sendButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                sendMessage(inputField.getText().trim());
+                inputField.setText("");
+            }
+        });
+    }
+
+    /**
+     * 连接到服务器
+     */
+    private void connectToServer() {
+        final String host = hostField.getText().trim();
+        final int port = Integer.parseInt(portField.getText().trim());
+
+        try {
+            // 打开Selector和SocketChannel
+            selector = Selector.open();
+            socketChannel = SocketChannel.open();
+            socketChannel.configureBlocking(false);
+            socketChannel.connect(new InetSocketAddress(host, port));
+            socketChannel.register(selector, SelectionKey.OP_CONNECT);
+
+            // 启动后台线程，处理服务器消息
+            running = true;
+            readThread = new Thread(this::readLoop, "NioClient-ReadThread");
+            readThread.start();
+
+            // 更新UI状态
+            connectButton.setText("断开");
+            appendMessage("正在连接到服务器 " + host + ":" + port + "...\n");
+        } catch (IOException e) {
+            appendMessage("连接失败: " + e.getMessage() + "\n");
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 断开与服务器的连接
+     */
+    private void disconnectFromServer() {
+        running = false;
+        try {
+            if (socketChannel != null) {
+                socketChannel.close();
+            }
+            if (selector != null) {
+                selector.wakeup();
+                selector.close();
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            socketChannel = null;
+            selector = null;
+            connectButton.setText("连接");
+            appendMessage("已断开连接。\n");
+        }
+    }
+
+    /**
+     * 发送消息给服务器
+     */
+    private void sendMessage(String msg) {
+        if (!running || socketChannel == null || !socketChannel.isOpen()) {
+            appendMessage("未连接服务器，无法发送消息。\n");
+            return;
+        }
+        if (msg.isEmpty()) {
+            return;
+        }
+        try {
+            socketChannel.write(ByteBuffer.wrap((msg + "\n").getBytes()));
+        } catch (IOException e) {
+            appendMessage("发送失败: " + e.getMessage() + "\n");
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 读取服务器消息的循环线程
+     */
+    private void readLoop() {
+        try {
+            while (running && selector != null && selector.isOpen()) {
+                // 阻塞等待事件
+                selector.select();
+
+                // 处理所有就绪事件
+                Iterator<SelectionKey> it = selector.selectedKeys().iterator();
+                while (it.hasNext()) {
+                    SelectionKey key = it.next();
+                    it.remove();
+
+                    if (!key.isValid()) {
+                        continue;
+                    }
+
+                    // 处理连接完成
+                    if (key.isConnectable()) {
+                        handleConnect(key);
+                    }
+
+                    // 处理可读
+                    if (key.isReadable()) {
+                        handleRead(key);
+                    }
+                }
+            }
+        } catch (IOException e) {
+            appendMessage("读取服务器消息时出现异常: " + e.getMessage() + "\n");
+            e.printStackTrace();
+        } finally {
+            // 读线程结束时进行清理
+            disconnectFromServer();
+        }
+    }
+
+    /**
+     * 处理连接完成
+     */
+    private void handleConnect(SelectionKey key) throws IOException {
+        SocketChannel sc = (SocketChannel) key.channel();
+        if (sc.isConnectionPending()) {
+            sc.finishConnect();
+        }
+        sc.configureBlocking(false);
+        sc.register(selector, SelectionKey.OP_READ);
+        appendMessage("已连接到服务器。\n");
+    }
+
+    /**
+     * 处理可读事件：从服务器接收数据
+     */
+    private void handleRead(SelectionKey key) throws IOException {
+        SocketChannel sc = (SocketChannel) key.channel();
+        ByteBuffer buffer = ByteBuffer.allocate(1024);
+
+        int readBytes = sc.read(buffer);
+        if (readBytes == -1) {
+            // 服务器端关闭
+            appendMessage("服务器已断开连接。\n");
+            running = false;
+            return;
+        }
+
+        if (readBytes > 0) {
+            buffer.flip();
+            // 按照简单文本协议，读到换行符即可作为一条消息
+            String msg = new String(buffer.array(), 0, buffer.limit()).trim();
+            appendMessage(msg + "\n");
+        }
+    }
+
+    /**
+     * 在UI文本框中追加消息 (线程安全)
+     */
+    private void appendMessage(String msg) {
+        SwingUtilities.invokeLater(() -> {
+            messageArea.append(msg);
+            // 自动滚动到末尾
+            messageArea.setCaretPosition(messageArea.getDocument().getLength());
+        });
+    }
+}

NIOChatServ/src/server/NioChatServer.java

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+package server;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.*;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class NioChatServer {
+
+    // 维护所有已连接的 SocketChannel
+    private static final ConcurrentHashMap<SocketChannel, String> clientMap = new ConcurrentHashMap<>();
+
+    public static void main(String[] args) {
+        // 端口可根据需要进行修改
+        int port = 8888;
+        try (Selector selector = Selector.open();
+             ServerSocketChannel serverSocketChannel = ServerSocketChannel.open()) {
+
+            // 配置为非阻塞
+            serverSocketChannel.configureBlocking(false);
+            // 绑定端口
+            serverSocketChannel.bind(new InetSocketAddress(port));
+            // 注册到 selector，监听 "接收新连接" 事件
+            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
+
+            System.out.println("服务器已启动，监听端口: " + port);
+
+            // 事件循环
+            while (true) {
+                // 阻塞等待就绪的通道
+                selector.select();
+                // 获取就绪的事件集合
+                Set<SelectionKey> selectionKeys = selector.selectedKeys();
+                Iterator<SelectionKey> iterator = selectionKeys.iterator();
+
+                while (iterator.hasNext()) {
+                    SelectionKey key = iterator.next();
+                    iterator.remove(); // 每次处理完一个事件后必须移除，避免重复处理
+
+                    try {
+                        // 处理新连接
+                        if (key.isAcceptable()) {
+                            handleAccept(key, selector);
+                        }
+                        // 处理可读事件
+                        if (key.isReadable()) {
+                            handleRead(key, selector);
+                        }
+                    } catch (IOException e) {
+                        // 发生异常时关闭连接并清理
+                        closeChannel(key);
+                    }
+                }
+            }
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 处理新客户端连接
+     */
+    private static void handleAccept(SelectionKey key, Selector selector) throws IOException {
+        ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
+        SocketChannel sc = ssc.accept();
+        if (sc == null) {
+            return;
+        }
+        // 配置为非阻塞
+        sc.configureBlocking(false);
+        // 注册到选择器中，关注读事件
+        sc.register(selector, SelectionKey.OP_READ);
+        // 将此客户端加入管理集合(如果需要，可以存储客户端的名称/ID等信息)
+        clientMap.put(sc, sc.getRemoteAddress().toString());
+        System.out.println("客户端连接: " + sc.getRemoteAddress());
+    }
+
+    /**
+     * 处理客户端发送的数据
+     */
+    private static void handleRead(SelectionKey key, Selector selector) throws IOException {
+        SocketChannel sc = (SocketChannel) key.channel();
+        ByteBuffer buffer = ByteBuffer.allocate(1024);
+
+        int readBytes = sc.read(buffer);
+        // 正常关闭或异常
+        if (readBytes == -1) {
+            closeChannel(key);
+            return;
+        }
+
+        // 如果有数据
+        if (readBytes > 0) {
+            buffer.flip();
+            String msg = new String(buffer.array(), 0, buffer.limit()).trim();
+
+            System.out.println("收到消息: " + msg + " 来自: " + clientMap.get(sc));
+
+            // 识别特殊命令
+            if ("EXIT".equalsIgnoreCase(msg)) {
+                // 关闭连接
+                System.out.println("客户端请求断开连接: " + clientMap.get(sc));
+                closeChannel(key);
+            } else if ("PING".equalsIgnoreCase(msg)) {
+                // 回复 PONG
+                String pong = "PONG\n";
+                sc.write(ByteBuffer.wrap(pong.getBytes()));
+            } else {
+                // 普通消息进行广播
+                broadcastMessage(sc, msg);
+            }
+        }
+    }
+
+    /**
+     * 向其他所有客户端广播消息
+     */
+    private static void broadcastMessage(SocketChannel sender, String msg) {
+        // 构造广播内容
+        String senderInfo = clientMap.get(sender);
+        String broadcastMsg = "[" + senderInfo + "] " + msg + "\n";
+
+        // 遍历所有连接的客户端, 写入消息
+        clientMap.forEach((channel, info) -> {
+            if (channel != sender && channel.isOpen()) {
+                try {
+                    channel.write(ByteBuffer.wrap(broadcastMsg.getBytes()));
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+    }
+
+    /**
+     * 关闭通道，清理资源
+     */
+    private static void closeChannel(SelectionKey key) {
+        try {
+            SocketChannel sc = (SocketChannel) key.channel();
+            System.out.println("连接关闭: " + clientMap.get(sc));
+            clientMap.remove(sc);
+            key.cancel();
+            sc.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}