仿牛客社区项目（第五章）（总）

系统管理员 2023-09-27 10:42 86阅读 0赞

#### 文章目录 ####

*  第三章：Kafka，构建TB级异步消息系统
 *  一、阻塞队列
 *   *  1. 阻塞队列测试方法
     *  2. 测试结果
 *  二、Kafka入门
 *   *  1. Kafka下载
     *  2. Kafka安装与配置
     *  3. Kafka的启动
     *  4. Kafka使用
 *  三、Spring整合Kafka
 *   *  1. 引入依赖
     *  2. 配置Kafka
     *  3. 测试
     *  4. 测试结果
 *  四、发送系统消息
 *   *  1. 实体类
     *  2. util包
     *  3. dao层
     *  4. service包
     *  5.controller层
     *  6. view层
 *  五、显示系统通知
 *   *  1. dao层
     *  2. service层
     *  3. controller层
     *  4. view层
     *  5. 功能测试
     *  5. 功能测试

## 第三章：Kafka，构建TB级异步消息系统 ##

## 一、阻塞队列 ##

*  `BlockingQueue`
    
     *  解决线程通信的问题。
     *  阻塞方法：`put`、`take`。
 *  生产者消费者模式
    
     *  生产者：产生数据的线程。
     *  消费者：使用数据的线程。
 *  实现类
    
     *  `ArrayBlockingQueue`
     *  `LinkedBlockingQueue`
     *  `PriorityBlockingQueue、SynchronousQueue、DelayQueue`等。

### 1. 阻塞队列测试方法 ###

在 `test` 中添加 `BlockingQueueTests`类，来表示阻塞队列的测试方法，代码如下：

public class BlockingQueueTests {
        public static void main(String[] args) {
            BlockingQueue queue = new ArrayBlockingQueue(10);
            new Thread(new Producer(queue)).start();
            new Thread(new Consumer(queue)).start();
            new Thread(new Consumer(queue)).start();
            new Thread(new Consumer(queue)).start();
        }
    }
    
    class Producer implements Runnable{
        private BlockingQueue<Integer> queue;
    
        public Producer(BlockingQueue<Integer> queue) {
            this.queue = queue;
        }
        @Override
        public void run(){
            try{
                for(int i = 0; i < 20; i ++ ) {
                    Thread.sleep(20);
                    queue.put(i);
                    System.out.println(Thread.currentThread().getName()+"生产："+ queue.size());
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
    
    class Consumer implements Runnable{
        private BlockingQueue<Integer> queue;
    
        public Consumer(BlockingQueue<Integer> queue) {
            this.queue = queue;
        }
    
        @Override
        public void run() {
            try {
                while (true){
                    Thread.sleep(new Random().nextInt(1000));
                    queue.take();
                    System.out.println(Thread.currentThread().getName()+"消费："+ queue.size());
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

### 2. 测试结果 ###

Thread-0生产：1
    Thread-0生产：2
    Thread-0生产：3
    Thread-0生产：4
    Thread-0生产：5
    Thread-0生产：6
    Thread-0生产：7
    Thread-0生产：8
    Thread-0生产：9
    Thread-0生产：10
    Thread-3消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-0生产：10
    Thread-2消费：9
    Thread-0生产：10
    Thread-3消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-0生产：10
    Thread-2消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-0生产：10
    Thread-3消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-0生产：10
    Thread-1消费：9
    Thread-1消费：8
    Thread-2消费：7
    Thread-1消费：6
    Thread-2消费：5
    Thread-1消费：4
    Thread-3消费：3
    Thread-3消费：2
    Thread-2消费：1
    Thread-3消费：0

## 二、Kafka入门 ##

*  Kafka简介
    
     *  Kafka是一个分布式的流媒体平台。
     *  应用：消息系统、日志收集、用户行为追踪、流式处理。
 *  Kafka特点
    
     *  高吞吐量、消息持久化、高可靠性、高扩展性。
 *  Kafka术语
    
     *  `Broker`、`Zookeeper`
     *  `Topic`、`Partition`、`Offset`
     *  `Leader Replica` 、`Follower Replica`

### 1. Kafka下载 ###

Kafka官网: `https://kafka.apache.org/`  
![在这里插入图片描述][02c9c805ba544d738d18e481e9d03ee8.png]

### 2. Kafka安装与配置 ###

下载Kafka的安装包后进行解压，就相当于安装成功了。  
**需要进行以下配置：**  
`修改 config包下的 zookeeper.properties:`  
![在这里插入图片描述][bf2d1d56d4e54302811bb7d9498c601b.png]  
`修改 config包下的 server.properties:`  
![在这里插入图片描述][ae416762bb3d466394d08f9f118a1d38.png]

### 3. Kafka的启动 ###

首先在命令行中启动 `Zookeeper`:

C:\Users\Andrew> d:
    D:\> cd d:\kafka_2.13-3.2.3
    d:\kafka_2.13-3.2.3>bin\windows\zookeeper-server-start.bat config\zookeeper.properties

启动成功后不关闭此窗口，重新打开一个新的命令窗口，用于启动 `kafka`：

C:\Users\Andrew> d:
    D:\> cd d:\kafka_2.13-3.2.3
    d:\kafka_2.13-3.2.3>bin\windows\kafka-server-start.bat config\server.properties

**注意：** 当遇到“‘wmic’不是内部或外部命令，也不是可运行程序”。  
在C盘下找到wbem文件夹，且里面包含WMIC.exe，将其添加到系统变量path中去。  
比如我的路径是：`C:\Windows\System32\wbem`，在系统变量path中新建该路径。就可以正常启动Kafka了。

### 4. Kafka使用 ###

*  创建主题  
    cd到 `…\kafka_2.13-2.8.0\bin\windows`这里，然后输入 `kafka-topics.bat --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic test`  
    创建服务器端口号为9092（`Kafka`默认端口号）的`topic`，指生产者发布消息存储的位置在该服务器上`localhost:9092`。`--replication-factor` 1 指1个副本。`--partitions` 1 指1个分区。`--topic test` 指该主题名为 `test`。  
    ![在这里插入图片描述][9cfe29663b324c3e8a16fb9111ac45ed.png]
 *  以生产者身份发送消息  
    输入：`kafka-console-producer.bat --broker-list localhost:9092 --topic test`  
    生产者身份打开服务器列表中为`localhost:9092`的服务器上的`test`主题。`--broker-list` 指服务器列表。  
    并且输入要发送的消息：  
    ![在这里插入图片描述][8ac42c35d3f04dacacef83535210c973.png]
 *  以消费者身份读取消息  
    新打开一个命令行窗口，且cd到`…\kafka_2.13-2.8.0\bin\windows`，并输入：`kafka-console-consumer.bat --bootstrap-server localhost:9092 --topic test --from-beginning`  
    可以看到生产者发送的消息。并且这个消息队列中可以实时传送消息。  
    比如在生产者的命令行中继续输入信息，很快在消费者这边也能得到消息。  
    ![在这里插入图片描述][e5501f06dcd94bf9908e7aedb133083e.png]

## 三、Spring整合Kafka ##

*  引入依赖
    
     *  `spring-kafka`
 *  配置Kafka
    
     *  配置 `server`、`consumer`
 *  访问Kafka
    
     *  生产者:  
        `kafkaTemplate.send(topic, data);`
     *  消费者:  
        `@KafkaListener(topics = {"test"}`  
        `public void handleMessage(ConsumerRecord record) {}`

### 1. 引入依赖 ###

在 `pom.xml` 添加相关的依赖：

<dependency>
    			<groupId>org.springframework.kafka</groupId>
    			<artifactId>spring-kafka</artifactId>
    			<version>2.8.6</version>
    		</dependency>

### 2. 配置Kafka ###

#KafkaProperties
    spring.kafka.bootstrap-servers=localhost:9092
    spring.kafka.consumer.group-id=test-consumer-group
    spring.kafka.consumer.enable-auto-commit=true
    spring.kafka.consumer.auto-commit-interval=3000

### 3. 测试 ###

在 `test` 包下添加 `KafkaTests` 类，代码如下：

@RunWith(SpringRunner.class)
    @SpringBootTest
    @ContextConfiguration(classes = CommunityApplication.class)
    public class KafkaTests {
    
        @Autowired
        private KafkaProducer kafkaProducer;
    
        @Test
        public void testKafka() {
            kafkaProducer.sendMessage("test", "你好");
            kafkaProducer.sendMessage("test", "在吗");
    
            try {
                Thread.sleep(1000 * 20);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    
    }
    
    @Component
    class KafkaProducer {
    
        @Autowired
        private KafkaTemplate kafkaTemplate;
    
        public void sendMessage(String topic, String content) {
            kafkaTemplate.send(topic, content);
        }
    
    }
    
    @Component
    class KafkaConsumer {
    
        @KafkaListener(topics = {"test"})
        public void handleMessage(ConsumerRecord record) {
            System.out.println(record.value());
        }
    }

### 4. 测试结果 ###

![在这里插入图片描述][a5647a6d4fd4433d8bbf314614e65cb9.png]

## 四、发送系统消息 ##

*  触发事件
    
     *  评论后，发布通知
     *  点赞后，发布通知
     *  关注后，发布通知
 *  处理事件
    
     *  封装事件对象
     *  开发事件的生产者
     *  开发事件的消费者

![在这里插入图片描述][b1326a7d4a9748b5b94e2d1fa16e5cde.png]

### 1. 实体类 ###

在 `entity` 包中添加 `Event` 实体类，代码如下：

public class Event {
    
        private String topic;
        private int userId;      //用户Id
        private int entityType;  //实体类型
        private int entityId;    //实体Id
        private int entityUserId;  //实体作者Id
        private Map<String,Object> data = new HashMap<>();
    
    
        public String getTopic() {
            return topic;
        }
    
        public Event setTopic(String topic) {
            this.topic = topic;
            return this;
        }
    
        public int getUserId() {
            return userId;
        }
    
        public Event setUserId(int userId) {
            this.userId = userId;
            return this;
        }
    
        public int getEntityType() {
            return entityType;
        }
    
        public Event setEntityType(int entityType) {
            this.entityType = entityType;
            return this;
        }
    
        public int getEntityId() {
            return entityId;
        }
    
        public Event setEntityId(int entityId) {
            this.entityId = entityId;
            return this;
        }
    
        public int getEntityUserId() {
            return entityUserId;
        }
    
        public Event setEntityUserId(int entityUserId) {
            this.entityUserId = entityUserId;
            return this;
        }
    
        public Map<String, Object> getData() {
            return data;
        }
    
        public Event setData(String key,Object value) {
            this.data.put(key,value);
            return this;
        }
    }

创建 `event` 包，添加 `EventProducer` 类 和 `EventConsumer` 类，代码如下：

@Component
    public class EventProducer {
    
        @Autowired
        private KafkaTemplate kafkaTemplate;
    
        //处理事件
        public void fireEvent(Event event){
            //将事件发布到指定的主题
            kafkaTemplate.send(event.getTopic(), JSONObject.toJSONString(event));
        }
    }

@Component
    public class EventConsumer implements CommunityConstant {
    
        private static final Logger logger = LoggerFactory.getLogger(EventConsumer.class);
    
        @Autowired
        private MessageService messageService;
    
        @KafkaListener(topics = {TOPIC_COMMENT, TOPIC_LIKE, TOPIC_FOLLOW})
        public void handleCommentMessage(ConsumerRecord record) {
            if (record == null || record.value() == null) {
                logger.error("消息的内容为空!");
                return;
            }
    
            Event event = JSONObject.parseObject(record.value().toString(), Event.class);
            if (event == null) {
                logger.error("消息格式错误!");
                return;
            }
    
            // 发送站内通知
            Message message = new Message();
            message.setFromId(SYSTEM_USER_ID);
            message.setToId(event.getEntityUserId());
            message.setConversationId(event.getTopic());
            message.setCreateTime(new Date());
    
            Map<String, Object> content = new HashMap<>();
            content.put("userId", event.getUserId());
            content.put("entityType", event.getEntityType());
            content.put("entityId", event.getEntityId());
    
            //这里代码要再盘一下 额外数据，比如postId
            if (!event.getData().isEmpty()) {
                for (Map.Entry<String, Object> entry : event.getData().entrySet()) {
                    content.put(entry.getKey(), entry.getValue());
                }
            }
    
            message.setContent(JSONObject.toJSONString(content));
            messageService.addMessage(message);
        }
    }

### 2. util包 ###

在 `CommunityConstant` 类中添加新的字段，代码如下：

public interface CommunityConstant {
    
        /**
         * 激活成功
         */
        int ACTIVATION_SUCCESS = 0;
    
        /**
         * 重复激活
         */
        int ACTIVATION_REPEAT = 1;
    
        /**
         * 激活失败
         */
        int ACTIVATION_FAILURE = 2;
    
        /**
         * 默认状态的登录凭证的超时时间
         */
        int DEFAULT_EXPIRED_SECONDS = 3600 * 12;
    
        /**
         * 记住状态的登录凭证超时时间
         */
        int REMEMBER_EXPIRED_SECONDS = 3600 * 24 * 100;
    
        /**
         * 实体类型: 帖子
         */
        int ENTITY_TYPE_POST = 1;
    
        /**
         * 实体类型: 评论
         */
        int ENTITY_TYPE_COMMENT = 2;
    
        /**
         * 实体类型：用户
         */
        int ENTITY_TYPE_USER = 3;
    
        /**
         * 主题: 评论
         */
        String TOPIC_COMMENT = "comment";
    
        /**
         * 主题: 点赞
         */
        String TOPIC_LIKE = "like";
    
        /**
         * 主题: 关注
         */
        String TOPIC_FOLLOW = "follow";
    
        /**
         * 系统用户ID
         */
        int SYSTEM_USER_ID = 1;
    
    }

### 3. dao层 ###

`CommentMapper`类中添加 `selectCommentById` 方法，代码如下：

@Mapper
    public interface CommentMapper {
            List<Comment> selectCommentsByEntity(int entityType, int entityId, int offset, int limit);
    
            int selectCountByEntity(int entityType, int entityId);
    
            int insertComment(Comment comment);
    
            Comment selectCommentById(int id);
            
    }

对应的 `comment-mapper.xml`代码如下：

### 4. service包 ###

在 `CommentService` 类中添加 `findCommentById` 方法，代码如下：

@Service
    public class CommentService implements CommunityConstant {
    
        @Autowired
        private CommentMapper commentMapper;
    
        @Autowired
        private SensitiveFilter sensitiveFilter;
    
        @Autowired
        private DiscussPostService discussPostService;
    
    
        public List<Comment> findCommentsByEntity(int entityType, int entityId, int offset, int limit) {
            return commentMapper.selectCommentsByEntity(entityType, entityId, offset, limit);
        }
    
        public int findCommentCount(int entityType, int entityId) {
            return commentMapper.selectCountByEntity(entityType, entityId);
        }
    
        @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
        public int addComment(Comment comment) {
            if (comment == null) {
                throw new IllegalArgumentException("参数不能为空！");
            }
            // 添加评论
            comment.setContent(HtmlUtils.htmlEscape(comment.getContent()));
            comment.setContent(sensitiveFilter.filter(comment.getContent()));
            int rows = commentMapper.insertComment(comment);
    
            // 更新帖子评论数量
            if (comment.getEntityType() == ENTITY_TYPE_POST) {
                int count = commentMapper.selectCountByEntity(comment.getEntityType(), comment.getEntityId());
                discussPostService.updateCommentCount(comment.getEntityId(), count);
            }
            return  rows;
        }
    
        public Comment findCommentById(int id) {
            return commentMapper.selectCommentById(id);
        }
    }

### 5.controller层 ###

在 `commentcontroller` 类中添加触发评论事件，代码如下：

@Controller
    @RequestMapping("/comment")
    public class CommentController implements CommunityConstant {
    
       @Autowired
       private CommentService commentService;
    
       @Autowired
       private HostHolder hostHolder;
    
       @Autowired
       private EventProducer eventProducer;
    
       @Autowired
       private DiscussPostService discussPostService;
    
       @RequestMapping(value = "/add/{discussPostId}", method = RequestMethod.POST)
       public String addComment(@PathVariable("discussPostId") int discussPostId, Comment comment) {
           comment.setUserId(hostHolder.getUser().getId());
           comment.setStatus(0);
           comment.setCreateTime(new Date());
           commentService.addComment(comment);
    
           // 触发评论事件
           Event event = new Event()
                   .setTopic(TOPIC_COMMENT)
                   .setUserId(hostHolder.getUser().getId())
                   .setEntityType(comment.getEntityType())
                   .setEntityId(comment.getEntityId())
                   .setData("postId", discussPostId);
           if (comment.getEntityType() == ENTITY_TYPE_POST) {
               DiscussPost target = discussPostService.findDiscussPostById(comment.getEntityId());
               event.setEntityUserId(target.getUserId());
           } else if (comment.getEntityType() == ENTITY_TYPE_COMMENT) {
               Comment target = commentService.findCommentById(comment.getEntityId());
               event.setEntityUserId(target.getUserId());
           }
           eventProducer.fireEvent(event);
    
           return "redirect:/discuss/detail/" + discussPostId;
       }
    }

在 `likecontroller` 类中添加触发点赞事件，代码如下：

@Controller
    public class LikeController implements CommunityConstant {
    
        @Autowired
        private LikeService likeService;
    
        @Autowired
        private HostHolder hostHolder;
    
        @Autowired
        private EventProducer eventProducer;
    
    
        @RequestMapping(path = "/like", method = RequestMethod.POST)
        @ResponseBody
        public String like(int entityType, int entityId, int entityUserId, int postId) {
            User user = hostHolder.getUser();
    
            // 点赞
            likeService.like(user.getId(), entityType, entityId, entityUserId);
    
            // 数量
            long likeCount = likeService.findEntityLikeCount(entityType, entityId);
            // 状态
            int likeStatus = likeService.findEntityLikeStatus(user.getId(), entityType, entityId);
            // 返回的结果
            Map<String, Object> map = new HashMap<>();
            map.put("likeCount", likeCount);
            map.put("likeStatus", likeStatus);
    
            // 触发点赞事件
            if (likeStatus == 1) {
                Event event = new Event()
                        .setTopic(TOPIC_LIKE)
                        .setUserId(hostHolder.getUser().getId())
                        .setEntityType(entityType)
                        .setEntityId(entityId)
                        .setEntityUserId(entityUserId)
                        .setData("postId", postId);  //postId对于点赞的是帖子而言，这个数据是冗余的
                eventProducer.fireEvent(event);
            }
    
    
            return CommunityUtil.getJSONString(0, null, map);
        }
    }

在 `followeController` 中添加触发关注事件，代码如下：

@Controller
    public class FollowController implements CommunityConstant {
    
        @Autowired
        private FollowService followService;
    
        @Autowired
        private HostHolder hostHolder;
    
        @Autowired
        private UserService userService;
    
        @Autowired
        private EventProducer eventProducer;
    
    
    
        @RequestMapping(path = "/follow", method = RequestMethod.POST)
        @ResponseBody
        public String follow(int entityType, int entityId) {
            User user = hostHolder.getUser();
    
            followService.follow(user.getId(), entityType, entityId);
    
            // 触发关注事件
            Event event = new Event()
                    .setTopic(TOPIC_FOLLOW)
                    .setUserId(hostHolder.getUser().getId())
                    .setEntityType(entityType)
                    .setEntityId(entityId)
                    .setEntityUserId(entityId);
            eventProducer.fireEvent(event);
    
    
            return CommunityUtil.getJSONString(0, "已关注！");
        }
    
        @RequestMapping(path = "/unfollow", method = RequestMethod.POST)
        @ResponseBody
        public String unfollow(int entityType, int entityId) {
            User user = hostHolder.getUser();
    
            followService.unfollow(user.getId(), entityType, entityId);
    
            return CommunityUtil.getJSONString(0, "已取消关注!");
        }
    
    
        @RequestMapping(path = "/followees/{userId}", method = RequestMethod.GET)
        public String getFollowees(@PathVariable("userId") int userId, Page page, Model model) {
            User user = userService.findUserById(userId);
            if (user == null) {
                throw new RuntimeException("该用户不存在!");
            }
            model.addAttribute("user", user);
    
            page.setLimit(5);
            page.setPath("/followees/" + userId);
            page.setRows((int) followService.findFolloweeCount(userId, ENTITY_TYPE_USER));
    
            List<Map<String, Object>> userList = followService.findFollowees(userId, page.getOffset(), page.getLimit());
            if (userList != null) {
                for (Map<String, Object> map : userList) {
                    User u = (User) map.get("user");
                    map.put("hasFollowed", hasFollowed(u.getId()));
                }
            }
            model.addAttribute("users", userList);
    
            return "/site/followee";
        }
    
        @RequestMapping(path = "/followers/{userId}", method = RequestMethod.GET)
        public String getFollowers(@PathVariable("userId") int userId, Page page, Model model) {
            User user = userService.findUserById(userId);
            if (user == null) {
                throw new RuntimeException("该用户不存在!");
            }
            model.addAttribute("user", user);
    
            page.setLimit(5);
            page.setPath("/followers/" + userId);
            page.setRows((int) followService.findFollowerCount(ENTITY_TYPE_USER, userId));
    
            List<Map<String, Object>> userList = followService.findFollowers(userId, page.getOffset(), page.getLimit());
            if (userList != null) {
                for (Map<String, Object> map : userList) {
                    User u = (User) map.get("user");
                    map.put("hasFollowed", hasFollowed(u.getId()));
                }
            }
            model.addAttribute("users", userList);
    
            return "/site/follower";
        }
    
    
        private boolean hasFollowed(int userId) {
            if (hostHolder.getUser() == null) {
                return false;
            }
    
            return followService.hasFollowed(hostHolder.getUser().getId(), ENTITY_TYPE_USER, userId);
        }
    
    
    }

### 6. view层 ###

对 `discudd-detail.html` 中的`like` 方法进行重构。  
`discuss.js`：

![在这里插入图片描述][976a471ebd6d4f97a4743135672ff64c.png]  
![在这里插入图片描述][0094fd6c3e3b42ad91b104c631b03d36.png]  
![在这里插入图片描述][97b50945fd2041b4b559f30c144a4ae1.png]  
![在这里插入图片描述][33bd0f8f545642c882f9d3e50a020411.png]  
![在这里插入图片描述][842c5ccc7ca546858dc90d6292b569e3.png]

## 五、显示系统通知 ##

*  通知列表
    
     *  显示评论、点赞、关注三种类型的通知
 *  通知详情
    
     *  分页显示某一类主题所包含的通知
 *  未读消息
    
     *  在页面头部显示所有的未读消息数量

### 1. dao层 ###

在 `MessageMapper` 类中添加 `selectLatestNotice`、`selectNoticeCount`、`selectNoticeUnreadCount`、`selectNotices` 方法，代码如下：

@Mapper
    public interface MessageMapper {
    
        // 查询当前用户的会话列表,针对每个会话只返回一条最新的私信.
        List<Message> selectConversations(int userId, int offset, int limit);
    
        // 查询当前用户的会话数量.
        int selectConversationCount(int userId);
    
        // 查询某个会话所包含的私信列表.
        List<Message> selectLetters(String conversationId, int offset, int limit);
    
        // 查询某个会话所包含的私信数量.
        int selectLetterCount(String conversationId);
    
        // 查询未读私信的数量
        int selectLetterUnreadCount(int userId, String conversationId);
    
        // 新增消息
        int insertMessage(Message message);
    
        // 修改消息的状态
        int updateStatus(List<Integer> ids, int status);
    
        // 查询某个主题下最新的通知
        Message selectLatestNotice(int userId, String topic);
    
        // 查询某个主题所包含的通知数量
        int selectNoticeCount(int userId, String topic);
    
        // 查询未读的通知的数量
        int selectNoticeUnreadCount(int userId, String topic);
    
        // 查询某个主题所包含的通知列表
        List<Message> selectNotices(int userId, String topic, int offset, int limit);
    
    }

对应的 `message-mapper.xml` 代码如下：

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.gerrard.community.dao.MessageMapper">
    
        <sql id="selectFields">
            id, from_id, to_id, conversation_id, content, status, create_time
        </sql>
    
        <sql id="insertFields">
            from_id, to_id, conversation_id, content, status, create_time
        </sql>
    
        <select id="selectConversations" resultType="Message">
            select <include refid="selectFields"></include>
            from message
            where id in (
                select max(id) from message
                where status != 2
                and from_id != 1
                and (from_id = #{userId} or to_id = #{userId})
                group by conversation_id
            )
            order by id desc
            limit #{offset}, #{limit}
        </select>
    
        <select id="selectConversationCount" resultType="int">
            select count(m.maxid) from (
                select max(id) as maxid from message
                where status != 2
                and from_id != 1
                and (from_id = #{userId} or to_id = #{userId})
                group by conversation_id
            ) as m
        </select>
    
        <select id="selectLetters" resultType="Message">
            select <include refid="selectFields"></include>
            from message
            where status != 2
            and from_id != 1
            and conversation_id = #{conversationId}
            order by id desc
            limit #{offset}, #{limit}
        </select>
    
        <select id="selectLetterCount" resultType="int">
            select count(id)
            from message
            where status != 2
            and from_id != 1
            and conversation_id = #{conversationId}
        </select>
    
        <select id="selectLetterUnreadCount" resultType="int">
            select count(id)
            from message
            where status = 0
            and from_id != 1
            and to_id = #{userId}
            <if test="conversationId!=null">
                and conversation_id = #{conversationId}
            </if>
        </select>
    
        <insert id="insertMessage" parameterType="Message" keyProperty="id">
            insert into message(<include refid="insertFields"></include>)
            values(#{fromId},#{toId},#{conversationId},#{content},#{status},#{createTime})
        </insert>
    
        <update id="updateStatus">
            update message set status = #{status}
            where id in
            <foreach collection="ids" item="id" open="(" separator="," close=")">
                #{id}
            </foreach>
        </update>
    
        <select id="selectLatestNotice" resultType="Message">
            select <include refid="selectFields"></include>
            from message
            where id in (
                select max(id) from message
                where status != 2
                and from_id = 1
                and to_id = #{userId}
                and conversation_id = #{topic}
            )
        </select>
    
        <select id="selectNoticeCount" resultType="int">
            select count(id) from message
            where status != 2
            and from_id = 1
            and to_id = #{userId}
            and conversation_id = #{topic}
        </select>
    
        <select id="selectNoticeUnreadCount" resultType="int">
            select count(id) from message
            where status = 0
            and from_id = 1
            and to_id = #{userId}
            <if test="topic!=null">
                and conversation_id = #{topic}
            </if>
        </select>
    
        <select id="selectNotices" resultType="Message">
            select <include refid="selectFields"></include>
            from message
            where status != 2
            and from_id = 1
            and to_id = #{userId}
            and conversation_id = #{topic}
            order by create_time desc
            limit #{offset}, #{limit}
        </select>
    
    </mapper>

### 2. service层 ###

在 `MessageService` 类中添加 `findLatesNotice`、`findNoticeCount` 、`findNoticeUnreadCount`、`findNotices`方法，代码如下：

### 3. controller层 ###

在 `MessageController` 类中添加 `getNoticeList`、`getNoticerDetail` 方法，代码如下：

@Controller
    public class MessageController implements CommunityConstant {
    
        @Autowired
        private MessageService messageService;
    
        @Autowired
        private HostHolder hostHolder;
    
        @Autowired
        private UserService userService;
    
        // 私信列表
        @RequestMapping(path = "/letter/list", method = RequestMethod.GET)
        public String getLetterList(Model model, Page page) {
            User user = hostHolder.getUser();
            // 分页信息
            page.setLimit(5);
            page.setPath("/letter/list");
            page.setRows(messageService.findConversationCount(user.getId()));
    
            // 会话列表
            List<Message> conversationList = messageService.findConversations(
                    user.getId(), page.getOffset(), page.getLimit());
            List<Map<String, Object>> conversations = new ArrayList<>();
            if (conversationList != null) {
                for (Message message : conversationList) {
                    Map<String, Object> map = new HashMap<>();
                    map.put("conversation", message);
                    map.put("letterCount", messageService.findLetterCount(message.getConversationId()));
                    map.put("unreadCount", messageService.findLetterUnreadCount(user.getId(), message.getConversationId()));
                    int targetId = user.getId() == message.getFromId() ? message.getToId() : message.getFromId();
                    map.put("target", userService.findUserById(targetId));
    
                    conversations.add(map);
                }
            }
            model.addAttribute("conversations", conversations);
    
            // 查询未读消息数量
            int letterUnreadCount = messageService.findLetterUnreadCount(user.getId(), null);
            model.addAttribute("letterUnreadCount", letterUnreadCount);
            int noticeUnreadCount = messageService.findNoticeUnreadCount(user.getId(), null);
            model.addAttribute("noticeUnreadCount", noticeUnreadCount);
    
            return "/site/letter";
        }
    
        @RequestMapping(path = "/letter/detail/{conversationId}", method = RequestMethod.GET)
        public String getLetterDetail(@PathVariable("conversationId") String conversationId, Page page, Model model) {
            // 分页信息
            page.setLimit(5);
            page.setPath("/letter/detail/" + conversationId);
            page.setRows(messageService.findLetterCount(conversationId));
    
            // 私信列表
            List<Message> letterList = messageService.findLetters(conversationId, page.getOffset(), page.getLimit());
            List<Map<String, Object>> letters = new ArrayList<>();
            if (letterList != null) {
                for (Message message : letterList) {
                    Map<String, Object> map = new HashMap<>();
                    map.put("letter", message);
                    map.put("fromUser", userService.findUserById(message.getFromId()));
                    letters.add(map);
                }
            }
            model.addAttribute("letters", letters);
    
            // 私信目标
            model.addAttribute("target", getLetterTarget(conversationId));
    
            // 设置已读
            List<Integer> ids = getLetterIds(letterList);
            if (!ids.isEmpty()) {
                messageService.readMessage(ids);
            }
    
            return "/site/letter-detail";
        }
    
        private User getLetterTarget(String conversationId) {
            String[] ids = conversationId.split("_");
            int id0 = Integer.parseInt(ids[0]);
            int id1 = Integer.parseInt(ids[1]);
    
            if (hostHolder.getUser().getId() == id0) {
                return userService.findUserById(id1);
            } else {
                return userService.findUserById(id0);
            }
        }
    
        private List<Integer> getLetterIds(List<Message> letterList) {
            List<Integer> ids = new ArrayList<>();
    
            if (letterList != null) {
                for (Message message : letterList) {
                    if (hostHolder.getUser().getId() == message.getToId() && message.getStatus() == 0) {
                        ids.add(message.getId());
                    }
                }
            }
    
            return ids;
        }
    
        @RequestMapping(path = "/letter/send", method = RequestMethod.POST)
        @ResponseBody
        public String sendLetter(String toName, String content) {
            User target = userService.findUserByName(toName);
            if (target == null) {
                return CommunityUtil.getJSONString(1, "目标用户不存在!");
            }
    
            Message message = new Message();
            message.setFromId(hostHolder.getUser().getId());
            message.setToId(target.getId());
            if (message.getFromId() < message.getToId()) {
                message.setConversationId(message.getFromId() + "_" + message.getToId());
            } else {
                message.setConversationId(message.getToId() + "_" + message.getFromId());
            }
            message.setContent(content);
            message.setCreateTime(new Date());
            messageService.addMessage(message);
    
            return CommunityUtil.getJSONString(0);
        }
    
        @RequestMapping(path = "/notice/list", method = RequestMethod.GET)
        public String getNoticeList(Model model) {
            User user = hostHolder.getUser();
    
            // 查询评论类通知
            Message message = messageService.findLatestNotice(user.getId(), TOPIC_COMMENT);
            Map<String, Object> messageVO = new HashMap<>();
            if (message != null) {
                messageVO.put("message", message);
    
                String content = HtmlUtils.htmlUnescape(message.getContent());
                Map<String, Object> data = JSONObject.parseObject(content, HashMap.class);
    
                messageVO.put("user", userService.findUserById((Integer) data.get("userId")));
                messageVO.put("entityType", data.get("entityType"));
                messageVO.put("entityId", data.get("entityId"));
                messageVO.put("postId", data.get("postId"));
    
                int count = messageService.findNoticeCount(user.getId(), TOPIC_COMMENT);
                messageVO.put("count", count);
    
                int unread = messageService.findNoticeUnreadCount(user.getId(), TOPIC_COMMENT);
                messageVO.put("unread", unread);
            }
            model.addAttribute("commentNotice", messageVO);
    
            // 查询点赞类通知
            message = messageService.findLatestNotice(user.getId(), TOPIC_LIKE);
            messageVO = new HashMap<>();
            if (message != null) {
                messageVO.put("message", message);
    
                String content = HtmlUtils.htmlUnescape(message.getContent());
                Map<String, Object> data = JSONObject.parseObject(content, HashMap.class);
    
                messageVO.put("user", userService.findUserById((Integer) data.get("userId")));
                messageVO.put("entityType", data.get("entityType"));
                messageVO.put("entityId", data.get("entityId"));
                messageVO.put("postId", data.get("postId"));
    
                int count = messageService.findNoticeCount(user.getId(), TOPIC_LIKE);
                messageVO.put("count", count);
    
                int unread = messageService.findNoticeUnreadCount(user.getId(), TOPIC_LIKE);
                messageVO.put("unread", unread);
            }
            model.addAttribute("likeNotice", messageVO);
    
            // 查询关注类通知
            message = messageService.findLatestNotice(user.getId(), TOPIC_FOLLOW);
            messageVO = new HashMap<>();
            if (message != null) {
                messageVO.put("message", message);
    
                String content = HtmlUtils.htmlUnescape(message.getContent());
                Map<String, Object> data = JSONObject.parseObject(content, HashMap.class);
    
                messageVO.put("user", userService.findUserById((Integer) data.get("userId")));
                messageVO.put("entityType", data.get("entityType"));
                messageVO.put("entityId", data.get("entityId"));
    
                int count = messageService.findNoticeCount(user.getId(), TOPIC_FOLLOW);
                messageVO.put("count", count);
    
                int unread = messageService.findNoticeUnreadCount(user.getId(), TOPIC_FOLLOW);
                messageVO.put("unread", unread);
            }
            model.addAttribute("followNotice", messageVO);
    
            // 查询未读消息数量
            int letterUnreadCount = messageService.findLetterUnreadCount(user.getId(), null);
            model.addAttribute("letterUnreadCount", letterUnreadCount);
            int noticeUnreadCount = messageService.findNoticeUnreadCount(user.getId(), null);
            model.addAttribute("noticeUnreadCount", noticeUnreadCount);
    
            return "/site/notice";
        }
    
        @RequestMapping(path = "/notice/detail/{topic}", method = RequestMethod.GET)
        public String getNoticeDetail(@PathVariable("topic") String topic, Page page, Model model) {
            User user = hostHolder.getUser();
    
            page.setLimit(5);
            page.setPath("/notice/detail/" + topic);
            page.setRows(messageService.findNoticeCount(user.getId(), topic));
    
            List<Message> noticeList = messageService.findNotices(user.getId(), topic, page.getOffset(), page.getLimit());
            List<Map<String, Object>> noticeVoList = new ArrayList<>();
            if (noticeList != null) {
                for (Message notice : noticeList) {
                    Map<String, Object> map = new HashMap<>();
                    // 通知
                    map.put("notice", notice);
                    // 内容
                    String content = HtmlUtils.htmlUnescape(notice.getContent());
                    Map<String, Object> data = JSONObject.parseObject(content, HashMap.class);
                    map.put("user", userService.findUserById((Integer) data.get("userId")));
                    map.put("entityType", data.get("entityType"));
                    map.put("entityId", data.get("entityId"));
                    map.put("postId", data.get("postId"));
                    // 通知作者
                    map.put("fromUser", userService.findUserById(notice.getFromId()));
    
                    noticeVoList.add(map);
                }
            }
            model.addAttribute("notices", noticeVoList);
    
            // 设置已读
            List<Integer> ids = getLetterIds(noticeList);
            if (!ids.isEmpty()) {
                messageService.readMessage(ids);
            }
    
            return "/site/notice-detail";
        }
    
    }

旧版：新建 `MessageInterceptor` 类拦截器。  
新版：在 `LoginTicketinterceptor` 中对 `posthandle` 方法进行修改，代码如下：

@Component
    public class LoginTicketInterceptor implements HandlerInterceptor {
        @Autowired
        private UserService userService;
    
        @Autowired
        private HostHolder hostHolder;
    
        @Autowired
        private MessageService messageService;
    
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            //从cookie中获取凭证
            String ticket= CookieUtil.getValue(request,"ticket");
            if(ticket!=null){
                //查询凭证
                LoginTicket loginTicket=userService.findLoginTicket(ticket);
    
                //检查凭证是否有效
                //一般不会检测到过期，因为时间一到，cookie自动被销毁了？？？？？
                if(loginTicket!=null && loginTicket.getStatus()==0 && loginTicket.getExpired().after(new Date())){
                    //根据凭证查询用户
                    User user=userService.findUserById(loginTicket.getUserId());
                    //在本次请求中持有用户
                    hostHolder.setUser(user);
    
                    //构建用户认证的结果，并存入SecurityContext，以便于Security进行授权
                    Authentication authentication=new UsernamePasswordAuthenticationToken(
                            user,user.getPassword(),userService.getAuthorities(user.getId()));
    
                    SecurityContextHolder.setContext(new SecurityContextImpl(authentication));
                }
            }
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
            User user=hostHolder.getUser();
    
            if(user!=null && modelAndView !=null){
                int unReadLetterCount=messageService.findLetterUnreadCount(user.getId(),null);
                int unReadNoticeCount=messageService.findNoticeUnreadCount(user.getId(),null);
                modelAndView.addObject("loginUser",user);
                modelAndView.addObject("messageUnRead",unReadLetterCount+unReadNoticeCount);
            }
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
            hostHolder.clear();
    
           // SecurityContextHolder.clearContext();
        }
    }

### 4. view层 ###

前端页面代码的修改在项目汇总中可进行查看。

### 5. 功能测试 ###

![在这里插入图片描述][1c8f59ce2278461681ca48ee455c88b5.png]

![在这里插入图片描述][6ee54b2b6f1f4194aa8d17165d502f31.png]  
![在这里插入图片描述][2d8d9a2e141f47ac8d32529592a89aff.png]

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