JavaWeb站內信系統 - 技術設計文檔

1. 系統概述

1.1 項目背景

本系統旨在為企業或社區平臺提供一套完整的站內信解決方案，支持用戶之間的消息發送、接收、管理等功能，提升用戶間的溝通效率。

1.2 設計目標

實現用戶間消息發送和接收
支持一對一和一對多消息發送
提供消息狀態跟蹤（已讀/未讀）
實現消息分類和管理
保證系統的高可用性和可擴展性

2. 技術架構

2.1 整體架構

表現層 (Web Layer)    -> Spring MVC + JSP/Thymeleaf
業務層 (Service Layer) -> Spring Service
持久層 (DAO Layer)    -> Spring Data JPA + Hibernate
數據庫 (Database)     -> MySQL 8.0
緩存層 (Cache)        -> Redis
消息隊列 (MQ)         -> RabbitMQ (可選)

2.2 技術選型

后端框架: Spring Boot 2.7.x
ORM框架: Spring Data JPA
數據庫: MySQL 8.0
緩存: Redis
前端: HTML5 + CSS3 + JavaScript + Bootstrap 5
構建工具: Maven
服務器: Tomcat 9+

3. 數據庫設計

3.1 數據庫ER圖

用戶(User) --(1:n)--> 站內信(Message)
用戶(User) --(1:n)--> 收件箱(MessageInbox)

3.2 數據表結構

用戶表 (sys_user)

CREATE TABLE `sys_user` (`user_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '用戶ID',`username` varchar(50) NOT NULL COMMENT '用戶名',`email` varchar(100) DEFAULT NULL COMMENT '郵箱',`status` tinyint(1) DEFAULT '1' COMMENT '狀態(0:禁用,1:啟用)',`create_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '創建時間',PRIMARY KEY (`user_id`),UNIQUE KEY `uniq_username` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='用戶表';

站內信表 (sys_message)

CREATE TABLE `sys_message` (`message_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '消息ID',`sender_id` bigint(20) NOT NULL COMMENT '發送者ID',`title` varchar(200) NOT NULL COMMENT '消息標題',`content` text NOT NULL COMMENT '消息內容',`message_type` tinyint(1) DEFAULT '1' COMMENT '消息類型(1:普通消息,2:系統通知,3:公告)',`priority` tinyint(1) DEFAULT '1' COMMENT '優先級(1:普通,2:重要,3:緊急)',`send_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '發送時間',`is_draft` tinyint(1) DEFAULT '0' COMMENT '是否為草稿(0:否,1:是)',PRIMARY KEY (`message_id`),KEY `idx_sender` (`sender_id`),KEY `idx_send_time` (`send_time`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='站內信表';

收件箱表 (sys_message_inbox)

CREATE TABLE `sys_message_inbox` (`inbox_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '收件箱ID',`message_id` bigint(20) NOT NULL COMMENT '消息ID',`receiver_id` bigint(20) NOT NULL COMMENT '接收者ID',`is_read` tinyint(1) DEFAULT '0' COMMENT '是否已讀(0:未讀,1:已讀)',`read_time` datetime DEFAULT NULL COMMENT '閱讀時間',`is_deleted` tinyint(1) DEFAULT '0' COMMENT '是否刪除(0:否,1:是)',`delete_time` datetime DEFAULT NULL COMMENT '刪除時間',PRIMARY KEY (`inbox_id`),UNIQUE KEY `uniq_message_receiver` (`message_id`, `receiver_id`),KEY `idx_receiver` (`receiver_id`),KEY `idx_is_read` (`is_read`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='收件箱表';

消息附件表 (sys_message_attachment)

CREATE TABLE `sys_message_attachment` (`attachment_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '附件ID',`message_id` bigint(20) NOT NULL COMMENT '消息ID',`file_name` varchar(255) NOT NULL COMMENT '文件名',`file_path` varchar(500) NOT NULL COMMENT '文件路徑',`file_size` bigint(20) DEFAULT '0' COMMENT '文件大小(字節)',`upload_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '上傳時間',PRIMARY KEY (`attachment_id`),KEY `idx_message` (`message_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='消息附件表';

4. 核心功能模塊設計

4.1 消息發送模塊

@Service
public class MessageServiceImpl implements MessageService {@Autowiredprivate MessageRepository messageRepository;@Autowiredprivate MessageInboxRepository messageInboxRepository;@Autowiredprivate UserRepository userRepository;@Autowiredprivate RabbitTemplate rabbitTemplate;@Override@Transactionalpublic ApiResponse sendMessage(MessageDTO messageDTO) {// 1. 驗證發送者身份User sender = userRepository.findById(messageDTO.getSenderId()).orElseThrow(() -> new BusinessException("發送者不存在"));// 2. 保存消息主體Message message = convertToEntity(messageDTO);messageRepository.save(message);// 3. 處理接收者if (messageDTO.getReceiverIds() != null && !messageDTO.getReceiverIds().isEmpty()) {List<MessageInbox> inboxList = new ArrayList<>();for (Long receiverId : messageDTO.getReceiverIds()) {User receiver = userRepository.findById(receiverId).orElseThrow(() -> new BusinessException("接收者ID[" + receiverId + "]不存在"));MessageInbox inbox = new MessageInbox();inbox.setMessageId(message.getMessageId());inbox.setReceiverId(receiverId);inbox.setIsRead(0);inboxList.add(inbox);}messageInboxRepository.saveAll(inboxList);// 4. 發送消息通知 (異步處理)sendMessageNotification(message, inboxList);}return ApiResponse.success("消息發送成功", message.getMessageId());}private void sendMessageNotification(Message message, List<MessageInbox> inboxList) {// 使用消息隊列異步發送通知Map<String, Object> notification = new HashMap<>();notification.put("messageId", message.getMessageId());notification.put("title", message.getTitle());notification.put("receiverIds", inboxList.stream().map(MessageInbox::getReceiverId).collect(Collectors.toList()));rabbitTemplate.convertAndSend("message.exchange", "message.notification", notification);}
}

4.2 消息接收與查詢模塊

@Service
public class MessageInboxServiceImpl implements MessageInboxService {@Autowiredprivate MessageInboxRepository messageInboxRepository;@Autowiredprivate MessageRepository messageRepository;@Overridepublic Page<MessageVO> getMessagesByUser(Long userId, MessageQueryDTO queryDTO, Pageable pageable) {// 構建查詢條件Specification<MessageInbox> spec = (root, query, cb) -> {List<Predicate> predicates = new ArrayList<>();predicates.add(cb.equal(root.get("receiverId"), userId));predicates.add(cb.equal(root.get("isDeleted"), 0));if (queryDTO.getIsRead() != null) {predicates.add(cb.equal(root.get("isRead"), queryDTO.getIsRead()));}if (StringUtils.isNotBlank(queryDTO.getKeyword())) {Join<MessageInbox, Message> messageJoin = root.join("message", JoinType.INNER);predicates.add(cb.or(cb.like(messageJoin.get("title"), "%" + queryDTO.getKeyword() + "%"),cb.like(messageJoin.get("content"), "%" + queryDTO.getKeyword() + "%")));}return cb.and(predicates.toArray(new Predicate[0]));};// 執行查詢Page<MessageInbox> inboxPage = messageInboxRepository.findAll(spec, pageable);// 轉換為VOreturn inboxPage.map(this::convertToVO);}@Override@Transactionalpublic void markAsRead(Long inboxId, Long userId) {MessageInbox inbox = messageInboxRepository.findById(inboxId).orElseThrow(() -> new BusinessException("消息不存在"));if (!inbox.getReceiverId().equals(userId)) {throw new BusinessException("無權操作此消息");}if (inbox.getIsRead() == 0) {inbox.setIsRead(1);inbox.setReadTime(new Date());messageInboxRepository.save(inbox);}}
}

4.3 消息推送模塊(WebSocket)

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {@Overridepublic void configureMessageBroker(MessageBrokerRegistry config) {config.enableSimpleBroker("/topic");config.setApplicationDestinationPrefixes("/app");}@Overridepublic void registerStompEndpoints(StompEndpointRegistry registry) {registry.addEndpoint("/ws-message").setAllowedOriginPatterns("*").withSockJS();}
}@Component
public class MessageWebSocketHandler {@Autowiredprivate SimpMessagingTemplate messagingTemplate;/*** 向指定用戶發送實時消息*/public void sendMessageToUser(Long userId, MessageVO message) {messagingTemplate.convertAndSendToUser(userId.toString(), "/topic/messages", message);}/*** 廣播系統消息*/public void broadcastSystemMessage(MessageVO message) {messagingTemplate.convertAndSend("/topic/system-messages", message);}
}

5. API接口設計

5.1 RESTful API設計

發送消息

POST /api/messages
Content-Type: application/json{"senderId": 1,"receiverIds": [2, 3, 4],"title": "會議通知","content": "本周五下午2點召開項目會議","messageType": 1,"priority": 2
}

獲取用戶消息列表

GET /api/messages/inbox?page=0&size=20&isRead=0&keyword=會議
Authorization: Bearer <token>

標記消息為已讀

PUT /api/messages/inbox/{inboxId}/read
Authorization: Bearer <token>

刪除消息

DELETE /api/messages/inbox/{inboxId}
Authorization: Bearer <token>

獲取未讀消息數量

GET /api/messages/inbox/unread-count
Authorization: Bearer <token>

6. 安全設計

6.1 權限控制

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {@Overrideprotected void configure(HttpSecurity http) throws Exception {http.authorizeRequests().antMatchers("/api/messages/send").hasAnyRole("USER", "ADMIN").antMatchers("/api/messages/**").authenticated().antMatchers("/api/admin/messages/**").hasRole("ADMIN").anyRequest().permitAll().and().csrf().disable().sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and().addFilterBefore(jwtAuthenticationFilter(), UsernamePasswordAuthenticationFilter.class);}
}

6.2 消息訪問權限驗證

@Component
public class MessagePermissionValidator {public boolean canAccessMessage(Long userId, Long messageId) {// 驗證用戶是否有權訪問此消息// 1. 用戶是發送者// 2. 用戶是接收者return messageInboxRepository.existsByReceiverIdAndMessageId(userId, messageId) ||messageRepository.existsBySenderIdAndMessageId(userId, messageId);}
}

7. 性能優化設計

7.1 數據庫優化

添加合適的索引
使用讀寫分離
大數據量表進行分表分庫

7.2 緩存策略

@Service
public class MessageCacheService {@Autowiredprivate RedisTemplate<String, Object> redisTemplate;private static final String UNREAD_COUNT_KEY = "message:unread:count:";private static final long CACHE_EXPIRE_HOURS = 24;/*** 獲取用戶未讀消息數量(帶緩存)*/public long getUnreadCountWithCache(Long userId) {String key = UNREAD_COUNT_KEY + userId;Object count = redisTemplate.opsForValue().get(key);if (count != null) {return Long.parseLong(count.toString());}long actualCount = messageInboxRepository.countByReceiverIdAndIsRead(userId, 0);redisTemplate.opsForValue().set(key, actualCount, CACHE_EXPIRE_HOURS, TimeUnit.HOURS);return actualCount;}/*** 清除未讀數量緩存*/public void clearUnreadCountCache(Long userId) {String key = UNREAD_COUNT_KEY + userId;redisTemplate.delete(key);}
}

7.3 異步處理

@Component
public class MessageAsyncProcessor {@Async("messageTaskExecutor")public void processMassMessage(Message message, List<Long> receiverIds) {// 分批處理大量接收者List<List<Long>> batches = Lists.partition(receiverIds, 1000);for (List<Long> batch : batches) {saveMessageInboxBatch(message.getMessageId(), batch);sendNotificationsBatch(message, batch);}}private void saveMessageInboxBatch(Long messageId, List<Long> receiverIds) {// 批量保存收件箱記錄List<MessageInbox> inboxList = receiverIds.stream().map(receiverId -> {MessageInbox inbox = new MessageInbox();inbox.setMessageId(messageId);inbox.setReceiverId(receiverId);inbox.setIsRead(0);return inbox;}).collect(Collectors.toList());messageInboxRepository.saveAll(inboxList);}
}

8. 部署架構

8.1 系統部署圖

負載均衡器 (Nginx)||-- 應用服務器集群 (Tomcat × 3)|       ||       |-- 站內信服務|       |-- WebSocket服務||-- 數據庫主從集群 (MySQL Master-Slave)||-- 緩存集群 (Redis Sentinel)||-- 消息隊列 (RabbitMQ集群)