tmp

week9/src/main/java/com/learn/Week9Application.java

@@ -0,0 +1,11 @@
+package com.learn;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Week9Application {
+    public static void main(String[] args) {
+        SpringApplication.run(Week9Application.class, args);
+    }
+}

week9/src/main/java/com/learn/config/AIConfig.java

@@ -0,0 +1,80 @@
+package com.learn.config;
+
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.ai.chat.client.advisor.MessageChatMemoryAdvisor;
+import org.springframework.ai.chat.memory.ChatMemory;
+import org.springframework.ai.chat.memory.InMemoryChatMemoryRepository;
+import org.springframework.ai.chat.memory.MessageWindowChatMemory;
+import org.springframework.ai.chat.model.ChatModel;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Spring AI 配置类（手动装配，便于理解各组件的关系）
+ *
+ * 架构:
+ *   ChatModel (OpenAiChatModel)    ← 底层 HTTP 通信，由 application.yml 自动配置
+ *       ↓ 包装
+ *   ChatClient                     ← 高级 Fluent API，我们手动创建
+ *       ↓ 拦截
+ *   MessageChatMemoryAdvisor       ← 自动注入对话历史（多轮对话）
+ *       ↓ 写入 / 读取
+ *   ChatMemory (MessageWindowChatMemory)  ← 滑动窗口记忆（默认保留最近 20 条）
+ *       ↓ 存储
+ *   ChatMemoryRepository (InMemoryChatMemoryRepository) ← ConcurrentHashMap 存储
+ *
+ * Spring AI 1.0.6 的架构变化：
+ *   - 旧版 InMemoryChatMemory 被拆分为两个角色：
+ *     ChatMemory（记忆策略）+ ChatMemoryRepository（存储实现）
+ *   - MessageChatMemoryAdvisor 构造函数私有化，必须用 Builder 创建
+ *   - 会话 ID 常量从 AbstractChatMemoryAdvisor 迁移到 ChatMemory 接口
+ */
+@Configuration
+public class AIConfig {
+
+    /**
+     * 对话记忆存储（内存实现，重启丢失）。
+     *
+     * InMemoryChatMemoryRepository = ConcurrentHashMap 包装
+     * MessageWindowChatMemory      = 滑动窗口策略（只保留最近 N 条消息）
+     *
+     * 生产环境可替换为 JdbcChatMemoryRepository 实现持久化。
+     */
+    @Bean
+    public ChatMemory chatMemory() {
+        var repository = new InMemoryChatMemoryRepository();
+        return MessageWindowChatMemory.builder()
+                .chatMemoryRepository(repository)
+                .maxMessages(20)   // 每个会话最多保留 20 条历史消息
+                .build();
+    }
+
+    /**
+     * ChatClient —— Spring AI 的推荐入口
+     *
+     * 构建步骤：
+     * 1. ChatClient.builder(chatModel)   —— 绑定底层的 ChatModel 实现
+     * 2. .defaultSystem(...)             —— 设置系统级角色 Prompt
+     * 3. .defaultAdvisors(...)           —— 注册 Advisor 拦截器链（如记忆管理）
+     * 4. .build()                        —— 创建不可变实例
+     *
+     * 关键点说明：
+     * - ChatClient 是线程安全的，整个应用共用一个单例
+     * - .defaultSystem() 对所有通过此 ChatClient 的请求生效
+     * - MessageChatMemoryAdvisor 会在每次请求前自动注入历史消息
+     * - 单次请求可通过 .system() 覆盖默认 System Prompt
+     */
+    @Bean
+    public ChatClient chatClient(ChatModel chatModel, ChatMemory chatMemory) {
+        return ChatClient.builder(chatModel)
+                .defaultSystem("""
+                        你是一个友好的 AI 助手，名字叫"小智"。
+                        请用中文回答用户的问题。
+                        如果你不知道答案，诚实地告诉用户，不要编造信息。
+                        """)
+                .defaultAdvisors(
+                        MessageChatMemoryAdvisor.builder(chatMemory).build()
+                )
+                .build();
+    }
+}

week9/src/main/java/com/learn/controller/ChatController.java

@@ -0,0 +1,93 @@
+package com.learn.controller;
+
+import com.learn.dto.ApiResponse;
+import com.learn.dto.ChatRequest;
+import com.learn.service.ChatService;
+import jakarta.validation.Valid;
+import org.springframework.http.MediaType;
+import org.springframework.http.codec.ServerSentEvent;
+import org.springframework.web.bind.annotation.*;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.util.Map;
+
+@RestController
+@RequestMapping("/api/chat")
+public class ChatController {
+
+    private final ChatService chatService;
+
+    public ChatController(ChatService chatService) {
+        this.chatService = chatService;
+    }
+
+    // ==================== Day 5: 同步对话 ====================
+
+    /**
+     * 同步聊天 —— 发送完整消息，等待完整回复。
+     *
+     * 请求: POST /api/chat
+     * Body: {"message": "你好", "conversationId": "会话ID（可选）"}
+     * 响应: {"code": 200, "data": {"reply": "你好！有什么可以帮你的？", "conversationId": "xxx"}}
+     */
+    @PostMapping
+    public ApiResponse<Map<String, String>> chat(@Valid @RequestBody ChatRequest request) {
+        String conversationId = request.getConversationId() != null
+                ? request.getConversationId() : "default";
+        String reply = chatService.chat(request.getMessage(), conversationId);
+        return ApiResponse.success(Map.of(
+                "reply", reply,
+                "conversationId", conversationId
+        ));
+    }
+
+    // ==================== Day 6: 流式对话 (SSE) ====================
+
+    /**
+     * 流式聊天 —— 逐 token 返回，打字机效果。
+     *
+     * 请求: POST /api/chat/stream
+     * Body: 同 /api/chat
+     * 响应: text/event-stream
+     *   data: 你
+     *   data: 好
+     *   data: ！
+     *   event: done
+     *   data: [DONE]
+     */
+    @PostMapping(value = "/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
+    public Flux<ServerSentEvent<String>> chatStream(@Valid @RequestBody ChatRequest request) {
+        return chatService.chatStream(request.getMessage(), request.getConversationId())
+                .map(token -> ServerSentEvent.<String>builder()
+                        .data(token)
+                        .build())
+                .concatWith(Mono.just(ServerSentEvent.<String>builder()
+                        .event("done")
+                        .data("[DONE]")
+                        .build()));
+    }
+
+    // ==================== Day 7: 历史管理 ====================
+
+    /**
+     * 查询某个会话的历史消息。
+     *
+     * GET /api/chat/history?conversationId=xxx
+     */
+    @GetMapping("/history")
+    public ApiResponse<?> getHistory(@RequestParam(defaultValue = "default") String conversationId) {
+        return ApiResponse.success(chatService.getHistory(conversationId));
+    }
+
+    /**
+     * 清除某个会话的历史。
+     *
+     * DELETE /api/chat/history?conversationId=xxx
+     */
+    @DeleteMapping("/history")
+    public ApiResponse<?> clearHistory(@RequestParam(defaultValue = "default") String conversationId) {
+        chatService.clearHistory(conversationId);
+        return ApiResponse.success("已清除会话: " + conversationId);
+    }
+}

week9/src/main/java/com/learn/dto/ApiResponse.java

@@ -0,0 +1,61 @@
+package com.learn.dto;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ApiResponse<T> {
+
+    private int code;
+    private String message;
+    private T data;
+    private Map<String, Object> extra;
+
+    public ApiResponse() {}
+
+    public ApiResponse(int code, String message, T data) {
+        this.code = code;
+        this.message = message;
+        this.data = data;
+    }
+
+    public static <T> ApiResponse<T> success(T data) {
+        return new ApiResponse<>(200, "success", data);
+    }
+
+    public static <T> ApiResponse<T> success(String message, T data) {
+        return new ApiResponse<>(200, message, data);
+    }
+
+    public static <T> ApiResponse<T> created(T data) {
+        return new ApiResponse<>(201, "created", data);
+    }
+
+    public static <T> ApiResponse<T> error(int code, String message) {
+        return new ApiResponse<>(code, message, null);
+    }
+
+    public static <T> ApiResponse<T> notFound(String message) {
+        return new ApiResponse<>(404, message, null);
+    }
+
+    public static <T> ApiResponse<T> badRequest(String message) {
+        return new ApiResponse<>(400, message, null);
+    }
+
+    public ApiResponse<T> put(String key, Object value) {
+        if (this.extra == null) {
+            this.extra = new HashMap<>();
+        }
+        this.extra.put(key, value);
+        return this;
+    }
+
+    public int getCode() { return code; }
+    public void setCode(int code) { this.code = code; }
+    public String getMessage() { return message; }
+    public void setMessage(String message) { this.message = message; }
+    public T getData() { return data; }
+    public void setData(T data) { this.data = data; }
+    public Map<String, Object> getExtra() { return extra; }
+    public void setExtra(Map<String, Object> extra) { this.extra = extra; }
+}

week9/src/main/java/com/learn/dto/ChatHistoryVo.java

@@ -0,0 +1,18 @@
+package com.learn.dto;
+
+import java.util.List;
+import java.util.Map;
+
+public class ChatHistoryVo {
+
+    private String conversationId;
+    private int messageCount;
+    private List<Map<String, Object>> messages;
+
+    public String getConversationId() { return conversationId; }
+    public void setConversationId(String conversationId) { this.conversationId = conversationId; }
+    public int getMessageCount() { return messageCount; }
+    public void setMessageCount(int messageCount) { this.messageCount = messageCount; }
+    public List<Map<String, Object>> getMessages() { return messages; }
+    public void setMessages(List<Map<String, Object>> messages) { this.messages = messages; }
+}

week9/src/main/java/com/learn/dto/ChatRequest.java

@@ -0,0 +1,16 @@
+package com.learn.dto;
+
+import jakarta.validation.constraints.NotBlank;
+
+public class ChatRequest {
+
+    @NotBlank(message = "消息不能为空")
+    private String message;
+
+    private String conversationId;
+
+    public String getMessage() { return message; }
+    public void setMessage(String message) { this.message = message; }
+    public String getConversationId() { return conversationId; }
+    public void setConversationId(String conversationId) { this.conversationId = conversationId; }
+}

week9/src/main/java/com/learn/exception/GlobalExceptionHandler.java

@@ -0,0 +1,39 @@
+package com.learn.exception;
+
+import com.learn.dto.ApiResponse;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<ApiResponse<?>> handleValidation(MethodArgumentNotValidException ex) {
+        var errors = new StringBuilder();
+        for (var error : ex.getBindingResult().getFieldErrors()) {
+            if (!errors.isEmpty()) errors.append("; ");
+            errors.append(error.getField()).append(": ").append(error.getDefaultMessage());
+        }
+        return ResponseEntity.badRequest()
+                .body(ApiResponse.badRequest("参数校验失败: " + errors));
+    }
+
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ResponseEntity<ApiResponse<?>> handleIllegalArgument(IllegalArgumentException ex) {
+        return ResponseEntity.badRequest()
+                .body(ApiResponse.badRequest(ex.getMessage()));
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ApiResponse<?>> handleAll(Exception ex) {
+        log.error("Unexpected error", ex);
+        return ResponseEntity.status(500)
+                .body(ApiResponse.error(500, "服务器内部错误: " + ex.getMessage()));
+    }
+}

week9/src/main/java/com/learn/service/ChatService.java

@@ -0,0 +1,118 @@
+package com.learn.service;
+
+import com.learn.dto.ChatHistoryVo;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.ai.chat.memory.ChatMemory;
+import org.springframework.stereotype.Service;
+import reactor.core.publisher.Flux;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.springframework.ai.chat.memory.ChatMemory.CONVERSATION_ID;
+
+@Service
+public class ChatService {
+
+    private static final Logger log = LoggerFactory.getLogger(ChatService.class);
+
+    private final ChatClient chatClient;
+    private final ChatMemory chatMemory;
+
+    public ChatService(ChatClient chatClient, ChatMemory chatMemory) {
+        this.chatClient = chatClient;
+        this.chatMemory = chatMemory;
+    }
+
+    // ==================== Day 5: 同步对话 ====================
+
+    /**
+     * 一问一答，等待完整回复后返回。
+     */
+    public String chat(String message) {
+        return chatClient.prompt()
+                .user(message)
+                .call()
+                .content();
+    }
+
+    // ==================== Day 6: 流式对话 ====================
+
+    /**
+     * 流式对话，逐 token 返回，实现"打字机效果"。
+     *
+     * @param message        用户消息
+     * @param conversationId 会话 ID（默认 "default"）
+     * @return Flux<String> 逐 token 流
+     */
+    public Flux<String> chatStream(String message, String conversationId) {
+        String convId = defaultIfNull(conversationId);
+        log.debug("Streaming chat for conversation: {}", convId);
+        return chatClient.prompt()
+                .user(message)
+                .advisors(a -> a.param(CONVERSATION_ID, convId))
+                .stream()
+                .content();
+    }
+
+    // ==================== Day 7: 多轮对话 ====================
+
+    /**
+     * 带上下文的多轮对话（非流式版）。
+     */
+    public String chat(String message, String conversationId) {
+        String convId = defaultIfNull(conversationId);
+        log.debug("Chat with memory, conversation: {}", convId);
+        return chatClient.prompt()
+                .user(message)
+                .advisors(a -> a.param(CONVERSATION_ID, convId))
+                .call()
+                .content();
+    }
+
+    /**
+     * 查询某个会话的历史消息。
+     */
+    public ChatHistoryVo getHistory(String conversationId) {
+        String convId = defaultIfNull(conversationId);
+        var messages = chatMemory.get(convId);
+        var list = new ArrayList<Map<String, Object>>();
+        for (var msg : messages) {
+            var item = new HashMap<String, Object>();
+            item.put("role", msg.getMessageType().name().toLowerCase());
+            item.put("content", msg.getText());
+            list.add(item);
+        }
+        ChatHistoryVo vo = new ChatHistoryVo();
+        vo.setConversationId(convId);
+        vo.setMessageCount(list.size());
+        vo.setMessages(list);
+        return vo;
+    }
+
+    /**
+     * 清除某个会话的所有历史。
+     */
+    public void clearHistory(String conversationId) {
+        String convId = defaultIfNull(conversationId);
+        chatMemory.clear(convId);
+        log.debug("Cleared history for conversation: {}", convId);
+    }
+
+    /**
+     * 获取所有会话 ID 列表。
+     */
+    public List<String> listConversations() {
+        // InMemoryChatMemory 没有直接列出所有 key 的方法
+        // 这里用一个简化方案：客户端自行管理会话 ID
+        return List.of();
+    }
+
+    private String defaultIfNull(String id) {
+        return (id == null || id.isBlank()) ? "default" : id;
+    }
+}

week9/src/main/resources/application.yml

@@ -0,0 +1,38 @@
+spring:
+  application:
+    name: week9-ai-chat
+
+  # =============================================================
+  # AI Provider Configuration (Spring AI)
+  # =============================================================
+  # 更换模型只需改两个地方:
+  #   1. base-url    → 服务商的 API 地址
+  #   2. model       → 模型名称
+  #
+  # 国内推荐 DeepSeek (注册送免费额度):
+  #   注册地址: https://platform.deepseek.com
+  #   API Key 获取: 登录后 → API Keys → 创建
+  #
+  # 备选: 阿里云百炼 Qwen (通义千问)
+  #   注册地址: https://bailian.console.aliyun.com
+  #
+  # 本地运行 (无需网络, 无需 API Key):
+  #   安装 Ollama: https://ollama.com
+  #   拉取模型: ollama pull qwen2.5:7b
+  # =============================================================
+  ai:
+    openai:
+      api-key: ${AI_API_KEY:sk-fe4d2f26eda04a659b9ff3408ce5024b}
+      base-url: ${AI_BASE_URL:https://api.deepseek.com}
+      chat:
+        options:
+          model: deepseek-chat
+          temperature: 0.7
+
+server:
+  port: 8080
+
+logging:
+  level:
+    com.learn: DEBUG
+    org.springframework.ai.chat.client.advisor: DEBUG

week9/src/main/resources/static/chat.html

@@ -0,0 +1,70 @@
+<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>AI 聊天机器人 - Week 9</title>
+    <link rel="stylesheet" href="/css/chat.css">
+</head>
+<body>
+
+<div class="app">
+    <!-- 侧边栏（Day 7） -->
+    <aside class="sidebar" id="sidebar">
+        <div class="sidebar-header">
+            <h2>对话列表</h2>
+        </div>
+        <button class="btn-new-chat" onclick="newConversation()">+ 新建对话</button>
+        <div class="conversation-list" id="conversation-list">
+            <div class="conv-item active" data-id="default" onclick="switchConversation('default')">
+                <span class="conv-title">默认对话</span>
+                <button class="conv-delete" onclick="event.stopPropagation(); deleteConversation('default')" title="删除">×</button>
+            </div>
+        </div>
+        <div class="sidebar-footer">
+            <select id="model-select" onchange="onModelChange()">
+                <option value="deepseek-chat">DeepSeek-Chat</option>
+                <option value="gpt-4o-mini">GPT-4o-mini</option>
+                <option value="qwen-turbo">Qwen-Turbo</option>
+            </select>
+        </div>
+    </aside>
+
+    <!-- 主聊天区 -->
+    <main class="chat-area">
+        <header class="chat-header">
+            <button class="btn-toggle-sidebar" onclick="toggleSidebar()" title="切换侧边栏">☰</button>
+            <h1>AI 聊天机器人</h1>
+            <span class="subtitle">Week 9 — Spring AI</span>
+        </header>
+
+        <div class="messages" id="messages">
+            <div class="welcome-msg">
+                <div class="welcome-icon">🤖</div>
+                <h3>你好！我是小智</h3>
+                <p>我是你的 AI 助手，有什么可以帮你的？</p>
+            </div>
+        </div>
+
+        <div class="input-area">
+            <div class="input-toolbar">
+                <label class="toggle-label">
+                    <input type="checkbox" id="stream-mode" checked>
+                    <span>流式输出</span>
+                </label>
+                <button class="btn-clear" onclick="clearCurrentHistory()">清除历史</button>
+            </div>
+            <div class="input-row">
+                <textarea id="user-input"
+                          placeholder="输入消息，按 Enter 发送，Shift+Enter 换行..."
+                          rows="1"
+                          onkeydown="handleKeyDown(event)"></textarea>
+                <button class="btn-send" id="send-btn" onclick="sendMessage()">发送</button>
+            </div>
+        </div>
+    </main>
+</div>
+
+<script src="/js/chat.js"></script>
+</body>
+</html>

week9/src/main/resources/static/css/chat.css

@@ -0,0 +1,277 @@
+/* ============================================================
+   Week 9 Chat UI — AI 聊天机器人样式
+   ============================================================ */
+
+* { margin: 0; padding: 0; box-sizing: border-box; }
+
+body {
+    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
+    background: #f0f2f5;
+    height: 100vh;
+    overflow: hidden;
+}
+
+/* ---- Layout ---- */
+.app {
+    display: flex;
+    height: 100vh;
+}
+
+/* ---- Sidebar ---- */
+.sidebar {
+    width: 260px;
+    background: #1e293b;
+    color: #cbd5e1;
+    display: flex;
+    flex-direction: column;
+    transition: transform 0.3s;
+}
+.sidebar.collapsed {
+    transform: translateX(-260px);
+    position: absolute;
+    z-index: 100;
+    height: 100%;
+}
+.sidebar-header {
+    padding: 20px 16px 12px;
+    border-bottom: 1px solid #334155;
+}
+.sidebar-header h2 { font-size: 16px; color: #f1f5f9; }
+
+.btn-new-chat {
+    margin: 12px 16px;
+    padding: 10px;
+    background: #3b82f6;
+    color: #fff;
+    border: none;
+    border-radius: 8px;
+    font-size: 14px;
+    cursor: pointer;
+    transition: background 0.2s;
+}
+.btn-new-chat:hover { background: #2563eb; }
+
+.conversation-list {
+    flex: 1;
+    overflow-y: auto;
+    padding: 0 8px;
+}
+.conv-item {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 10px 12px;
+    margin: 2px 0;
+    border-radius: 8px;
+    cursor: pointer;
+    font-size: 14px;
+    transition: background 0.15s;
+}
+.conv-item:hover { background: #334155; }
+.conv-item.active { background: #3b82f6; color: #fff; }
+.conv-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.conv-delete {
+    background: none;
+    border: none;
+    color: inherit;
+    font-size: 18px;
+    cursor: pointer;
+    opacity: 0;
+    transition: opacity 0.15s;
+    padding: 0 4px;
+}
+.conv-item:hover .conv-delete { opacity: 0.6; }
+.conv-delete:hover { opacity: 1 !important; }
+
+.sidebar-footer { padding: 12px 16px; border-top: 1px solid #334155; }
+.sidebar-footer select {
+    width: 100%;
+    padding: 8px;
+    background: #334155;
+    color: #f1f5f9;
+    border: 1px solid #475569;
+    border-radius: 6px;
+    font-size: 13px;
+}
+
+/* ---- Chat Area ---- */
+.chat-area {
+    flex: 1;
+    display: flex;
+    flex-direction: column;
+    background: #fff;
+    min-width: 0;
+}
+
+.chat-header {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    padding: 14px 20px;
+    border-bottom: 1px solid #e5e7eb;
+    background: #fafbfc;
+}
+.chat-header h1 { font-size: 18px; color: #1e293b; }
+.chat-header .subtitle { font-size: 13px; color: #94a3b8; }
+.btn-toggle-sidebar {
+    background: none;
+    border: none;
+    font-size: 20px;
+    cursor: pointer;
+    padding: 4px 8px;
+    border-radius: 4px;
+    color: #64748b;
+}
+.btn-toggle-sidebar:hover { background: #e2e8f0; }
+
+/* ---- Messages ---- */
+.messages {
+    flex: 1;
+    overflow-y: auto;
+    padding: 20px 24px;
+    display: flex;
+    flex-direction: column;
+    gap: 16px;
+}
+
+.welcome-msg {
+    text-align: center;
+    margin: auto;
+    color: #94a3b8;
+}
+.welcome-icon { font-size: 48px; margin-bottom: 12px; }
+.welcome-msg h3 { font-size: 20px; color: #475569; margin-bottom: 6px; }
+.welcome-msg p { font-size: 14px; }
+
+/* ---- Message Bubbles ---- */
+.msg {
+    display: flex;
+    gap: 10px;
+    max-width: 80%;
+    animation: fadeIn 0.3s ease;
+}
+@keyframes fadeIn {
+    from { opacity: 0; transform: translateY(8px); }
+    to { opacity: 1; transform: translateY(0); }
+}
+
+.msg.user {
+    align-self: flex-end;
+    flex-direction: row-reverse;
+}
+
+.msg .avatar {
+    width: 36px;
+    height: 36px;
+    border-radius: 50%;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    font-size: 16px;
+    flex-shrink: 0;
+}
+.msg.assistant .avatar { background: #e0e7ff; }
+.msg.user .avatar { background: #dbeafe; }
+
+.msg .bubble {
+    padding: 10px 14px;
+    border-radius: 12px;
+    font-size: 14px;
+    line-height: 1.6;
+    white-space: pre-wrap;
+    word-break: break-word;
+}
+.msg.assistant .bubble {
+    background: #f1f5f9;
+    color: #1e293b;
+    border-bottom-left-radius: 4px;
+}
+.msg.user .bubble {
+    background: #3b82f6;
+    color: #fff;
+    border-bottom-right-radius: 4px;
+}
+
+/* Streaming cursor */
+.msg.streaming .bubble::after {
+    content: '▊';
+    animation: blink 1s infinite;
+    color: #3b82f6;
+}
+.msg.streaming.user .bubble::after { color: #fff; }
+@keyframes blink {
+    0%, 50% { opacity: 1; }
+    51%, 100% { opacity: 0; }
+}
+
+/* ---- Input Area ---- */
+.input-area {
+    padding: 12px 20px 16px;
+    border-top: 1px solid #e5e7eb;
+    background: #fafbfc;
+}
+.input-toolbar {
+    display: flex;
+    align-items: center;
+    gap: 16px;
+    margin-bottom: 8px;
+}
+.toggle-label {
+    display: flex;
+    align-items: center;
+    gap: 6px;
+    font-size: 13px;
+    color: #64748b;
+    cursor: pointer;
+}
+.btn-clear {
+    background: none;
+    border: none;
+    color: #94a3b8;
+    font-size: 12px;
+    cursor: pointer;
+    padding: 4px 0;
+}
+.btn-clear:hover { color: #ef4444; }
+
+.input-row {
+    display: flex;
+    gap: 10px;
+    align-items: flex-end;
+}
+#user-input {
+    flex: 1;
+    padding: 10px 14px;
+    border: 1px solid #d1d5db;
+    border-radius: 10px;
+    font-size: 14px;
+    font-family: inherit;
+    resize: none;
+    outline: none;
+    transition: border-color 0.2s;
+    max-height: 120px;
+}
+#user-input:focus { border-color: #3b82f6; }
+
+.btn-send {
+    padding: 10px 20px;
+    background: #3b82f6;
+    color: #fff;
+    border: none;
+    border-radius: 10px;
+    font-size: 14px;
+    cursor: pointer;
+    transition: background 0.2s;
+    flex-shrink: 0;
+}
+.btn-send:hover { background: #2563eb; }
+.btn-send:disabled {
+    background: #93c5fd;
+    cursor: not-allowed;
+}
+
+/* ---- Responsive ---- */
+@media (max-width: 640px) {
+    .sidebar { display: none; }
+    .msg { max-width: 90%; }
+}

week9/src/main/resources/static/js/chat.js

@@ -0,0 +1,272 @@
+/**
+ * Week 9 Chat JS — AI 聊天机器人前端逻辑
+ *
+ * 涵盖 Day 5 (同步), Day 6 (SSE 流式), Day 7 (多轮对话管理)
+ */
+
+// ---- 全局状态 ----
+let currentConversationId = 'default';
+const conversations = new Map(); // id -> { title, lastTime }
+conversations.set('default', { title: '默认对话', lastTime: Date.now() });
+
+// ---- DOM 引用 ----
+const messagesEl = document.getElementById('messages');
+const inputEl = document.getElementById('user-input');
+const sendBtn = document.getElementById('send-btn');
+const streamToggle = document.getElementById('stream-mode');
+const convListEl = document.getElementById('conversation-list');
+
+// ---- 工具函数 ----
+function generateId() {
+    return 'conv_' + Date.now() + '_' + Math.random().toString(36).substring(2, 8);
+}
+
+function escapeHtml(text) {
+    const div = document.createElement('div');
+    div.textContent = text;
+    return div.innerHTML;
+}
+
+// ---- UI 渲染 ----
+function removeWelcome() {
+    const welcome = messagesEl.querySelector('.welcome-msg');
+    if (welcome) welcome.remove();
+}
+
+function createMsgElement(role) {
+    const div = document.createElement('div');
+    div.className = 'msg ' + role;
+    const avatar = document.createElement('div');
+    avatar.className = 'avatar';
+    avatar.textContent = role === 'user' ? '👤' : '🤖';
+    const bubble = document.createElement('div');
+    bubble.className = 'bubble';
+    div.appendChild(avatar);
+    div.appendChild(bubble);
+    messagesEl.appendChild(div);
+    return div;
+}
+
+function scrollToBottom() {
+    messagesEl.scrollTop = messagesEl.scrollHeight;
+}
+
+// ---- Day 5: 同步发送 ----
+async function sendSyncMessage(message) {
+    const response = await fetch('/api/chat', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ message, conversationId: currentConversationId })
+    });
+    const result = await response.json();
+    if (result.code !== 200) {
+        throw new Error(result.message || '请求失败');
+    }
+    return result.data.reply;
+}
+
+// ---- Day 6: SSE 流式发送 ----
+async function sendStreamMessage(message) {
+    const response = await fetch('/api/chat/stream', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ message, conversationId: currentConversationId })
+    });
+
+    if (!response.ok) {
+        const err = await response.json();
+        throw new Error(err.message || '流式请求失败');
+    }
+
+    const reader = response.body.getReader();
+    const decoder = new TextDecoder();
+    let buffer = '';
+
+    return {
+        async *[Symbol.asyncIterator]() {
+            while (true) {
+                const { done, value } = await reader.read();
+                if (done) break;
+
+                buffer += decoder.decode(value, { stream: true });
+                const lines = buffer.split('\n');
+                buffer = lines.pop() || '';
+
+                for (const line of lines) {
+                    const trimmed = line.trim();
+                    if (!trimmed.startsWith('data:')) continue;
+
+                    const data = trimmed.slice(5).trim();
+                    if (data === '[DONE]') return;
+                    yield data;
+                }
+            }
+        }
+    };
+}
+
+// ---- 主发送流程 ----
+async function sendMessage() {
+    const message = inputEl.value.trim();
+    if (!message) return;
+
+    // 禁用输入
+    inputEl.value = '';
+    inputEl.style.height = 'auto';
+    sendBtn.disabled = true;
+    inputEl.disabled = true;
+
+    removeWelcome();
+
+    // 渲染用户消息
+    const userMsgEl = createMsgElement('user');
+    userMsgEl.querySelector('.bubble').textContent = message;
+    scrollToBottom();
+
+    // 渲染 AI 消息占位
+    const aiMsgEl = createMsgElement('assistant');
+    const aiBubble = aiMsgEl.querySelector('.bubble');
+
+    try {
+        if (streamToggle.checked) {
+            // ---- 流式模式 ----
+            aiMsgEl.classList.add('streaming');
+            aiBubble.textContent = '';
+            const stream = await sendStreamMessage(message);
+
+            for await (const token of stream) {
+                aiBubble.textContent += token;
+                scrollToBottom();
+            }
+            aiMsgEl.classList.remove('streaming');
+
+        } else {
+            // ---- 同步模式 ----
+            aiBubble.textContent = '思考中...';
+            const reply = await sendSyncMessage(message);
+            aiBubble.textContent = reply;
+            scrollToBottom();
+        }
+
+        // 更新会话信息
+        const conv = conversations.get(currentConversationId);
+        if (conv) {
+            conv.lastTime = Date.now();
+            if (conv.title === '默认对话' || conv.title === '新对话') {
+                conv.title = message.substring(0, 20) + (message.length > 20 ? '...' : '');
+            }
+        }
+        renderConversationList();
+
+    } catch (error) {
+        aiMsgEl.classList.remove('streaming');
+        aiBubble.textContent = '错误: ' + error.message;
+        aiBubble.style.color = '#ef4444';
+        console.error('Chat error:', error);
+    } finally {
+        sendBtn.disabled = false;
+        inputEl.disabled = false;
+        inputEl.focus();
+    }
+}
+
+// ---- 键盘处理 ----
+function handleKeyDown(event) {
+    if (event.key === 'Enter' && !event.shiftKey) {
+        event.preventDefault();
+        sendMessage();
+    }
+}
+
+// 自动调整 textarea 高度
+inputEl.addEventListener('input', () => {
+    inputEl.style.height = 'auto';
+    inputEl.style.height = Math.min(inputEl.scrollHeight, 120) + 'px';
+});
+
+// ---- Day 7: 会话管理 ----
+function switchConversation(id) {
+    currentConversationId = id;
+    messagesEl.innerHTML = `
+        <div class="welcome-msg">
+            <div class="welcome-icon">🤖</div>
+            <h3>会话已切换</h3>
+            <p>当前会话: ${escapeHtml(conversations.get(id)?.title || id)}</p>
+        </div>`;
+    renderConversationList();
+}
+
+function newConversation() {
+    const id = generateId();
+    conversations.set(id, { title: '新对话', lastTime: Date.now() });
+    currentConversationId = id;
+    messagesEl.innerHTML = `
+        <div class="welcome-msg">
+            <div class="welcome-icon">💬</div>
+            <h3>新对话已创建</h3>
+            <p>开始和 AI 聊天吧！</p>
+        </div>`;
+    renderConversationList();
+}
+
+async function deleteConversation(id) {
+    if (id === 'default') return;
+    conversations.delete(id);
+    try {
+        await fetch(`/api/chat/history?conversationId=${id}`, { method: 'DELETE' });
+    } catch (e) { /* ignore */ }
+    if (currentConversationId === id) {
+        currentConversationId = 'default';
+        switchConversation('default');
+    }
+    renderConversationList();
+}
+
+async function clearCurrentHistory() {
+    if (!confirm('确定清除当前会话的所有历史消息？')) return;
+    try {
+        await fetch(`/api/chat/history?conversationId=${currentConversationId}`, { method: 'DELETE' });
+    } catch (e) { /* ignore */ }
+    messagesEl.innerHTML = `
+        <div class="welcome-msg">
+            <div class="welcome-icon">🧹</div>
+            <h3>历史已清除</h3>
+            <p>当前会话的记忆已清空，开始新的对话吧！</p>
+        </div>`;
+}
+
+function onModelChange() {
+    alert('模型切换需要在 application.yml 中修改 spring.ai.openai.chat.options.model 并重启应用。\n此处仅作演示。');
+}
+
+function renderConversationList() {
+    convListEl.innerHTML = '';
+    const sorted = [...conversations.entries()]
+        .sort((a, b) => b[1].lastTime - a[1].lastTime);
+    for (const [id, conv] of sorted) {
+        const item = document.createElement('div');
+        item.className = 'conv-item' + (id === currentConversationId ? ' active' : '');
+        item.setAttribute('data-id', id);
+        item.onclick = () => switchConversation(id);
+        item.innerHTML = `
+            <span class="conv-title">${escapeHtml(conv.title)}</span>
+            ${id !== 'default' ? `<button class="conv-delete" title="删除">×</button>` : ''}`;
+
+        const delBtn = item.querySelector('.conv-delete');
+        if (delBtn) {
+            delBtn.onclick = (e) => {
+                e.stopPropagation();
+                deleteConversation(id);
+            };
+        }
+        convListEl.appendChild(item);
+    }
+}
+
+function toggleSidebar() {
+    document.getElementById('sidebar').classList.toggle('collapsed');
+}
+
+// ---- 初始化 ----
+renderConversationList();
+inputEl.focus();