@Service
public class EventConsumer implements InitializingBean, ApplicationContextAware {
    private static final Logger logger = LoggerFactory.getLogger(EventConsumer.class);
    private Map<EventType, List<EventHandler>> config = new HashMap<>();
    private ApplicationContext applicationContext;
    @Autowired
    private JedisAdapter jedisAdapter;

    @Override
    public void afterPropertiesSet() throws Exception {
        Map<String, EventHandler> beans = applicationContext.getBeansOfType(EventHandler.class);
        if (beans != null) {
            for (Map.Entry<String, EventHandler> entry : beans.entrySet()) {
                List<EventType> eventTypes = entry.getValue().getSupportEventTypes();
                for (EventType type : eventTypes) {
                    if (!config.containsKey(type)) {
                        config.put(type, new ArrayList<EventHandler>());
                    }

                    // 註冊每個事件的處理函式
                    config.get(type).add(entry.getValue());
                }
            }
        }

        // 啟動執行緒去消費事件
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                // 從佇列一直消費
                while (true) {
                    String key = RedisKeyUtil.getEventQueueKey();
                    List<String> messages = jedisAdapter.brpop(0, key);
                    // 第一個元素是佇列名字
                    for (String message : messages) {
                        if (message.equals(key)) {
                            continue;
                        }

                        EventModel eventModel = JSON.parseObject(message, EventModel.class);
                        // 找到這個事件的處理handler列表
                        if (!config.containsKey(eventModel.getType())) {
                            logger.error("不能識別的事件");
                            continue;
                        }

                        for (EventHandler handler : config.get(eventModel.getType())) {
                            handler.doHandle(eventModel);
                        }
                    }
                }
            }
        });
        thread.start();
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }
}
 

6.寫一個實現了EventHandler介面的實現

@Component
public class LikeHandler implements EventHandler {
    @Autowired
    MessageService messageService;

    @Autowired
    UserService userService;

    @Override
    public void doHandle(EventModel model) {
        Message message = new Message();
        User user = userService.getUser(model.getActorId());
        message.setToId(model.getEntityOwnerId());
        message.setContent("使用者" + user.getName() +
                " 讚了你的資訊,http://127.0.0.1:8080/news/"
                + String.valueOf(model.getEntityId()));
        // SYSTEM ACCOUNT
        message.setFromId(3);
        message.setCreatedDate(new Date());
        messageService.addMessage(message);
    }

    @Override
    public List<EventType> getSupportEventTypes() {
        return Arrays.asList(EventType.LIKE);
    }
}
 

7.在Controller中呼叫Producer的fireEvent -- 用於產生一個事件