这里我用到了Redis当中的发布订阅模式实现(JAVA代码实现)
先看图示
下面为代码实现
首先将RedisMessageListenerContainer交给Spring管理.
@Configuration
public class redisConfig {@AutowiredRedisConnectionFactory redisConnectionFactory;@Autowired@Qualifier("carServiceDb")private CarService carService;//操作数据库@Beanpublic RedisMessageListenerContainer listenerContainer(){//创建一个Redis消息监听器容器对象RedisMessageListenerContainer listenerContainer = new RedisMessageListenerContainer();//设置Redis连接工厂对象listenerContainer.setConnectionFactory(redisConnectionFactory);//向监听器容器中添加一个监听器，该监听器的主题为INSERTEDlistenerContainer.addMessageListener(new MessageListener() {@Overridepublic void onMessage(Message message, byte[] pattern) {System.out.println("*************insert*************");String carJsonStr = new String(message.getBody());Car car = JSONObject.parseObject(carJsonStr, Car.class);carService.addCar(car);System.out.println(new String(message.getBody()));System.out.println(new String(pattern));System.out.println("*************insert*************");}}, new ChannelTopic(ChannelEnum.INSERTED.name()));//向监听器容器中添加一个监听器，该监听器的主题为UPDATEDlistenerContainer.addMessageListener(new MessageListener() {@Overridepublic void onMessage(Message message, byte[] pattern) {System.out.println("*************UPDATED*************");String carJsonStr = new String(message.getBody());Car car = JSONObject.parseObject(carJsonStr, Car.class);carService.updataCount(car.getBookId(),car.getNumber(),car.getUserId());System.out.println(new String(message.getBody()));System.out.println(new String(pattern));System.out.println("*************UPDATED*************");}}, new ChannelTopic(ChannelEnum.UPDATED.name()));//向监听器容器中添加一个监听器，该监听器的主题为DELETEDlistenerContainer.addMessageListener(new MessageListener() {@Overridepublic void onMessage(Message message, byte[] pattern) {System.out.println("*************DELETED*************");System.out.println(new String(message.getBody()));System.out.println(new String(pattern));List<String[]> strings = JSONArray.parseArray(new String(message.getBody()), String[].class);String[] bookIds = strings.get(0);String userId = strings.get(1)[0];carService.delCar(bookIds,userId);System.out.println("----------------------");System.out.println(Arrays.toString(bookIds));System.out.println(userId);System.out.println("--------delete--------");System.out.println("*************DELETED*************");}}, new ChannelTopic(ChannelEnum.DELETED.name()));return listenerContainer;}
}下面代码中的 stringRedisTemplate.convertAndSend();就是发送消息的，其中参数1是发送消息的名称，参数2是发送消息的内容
@Service("carService")
@Slf4j
public class CarServiceImpl extends ServiceImpl<CarMapper, Car> implements CarService {//购物车hash的Keypublic static final String CAR_KEY = "carKey";//hash购物车中field的前缀public static final String USER_CAR_HASH_FIELD_PREFIX = "car::";@Resourceprivate StringRedisTemplate stringRedisTemplate;/*** 这里存储的时候采用Redis当中的hash存储** @param car*/@Override@Synchronizedpublic void addCar(Car car) {//这里存储的时候采用Redis当中的hash存储HashOperations<String, String, String> opsForHash = stringRedisTemplate.opsForHash();//这里field为CAR_HASH_FIELDString userCarKey = USER_CAR_HASH_FIELD_PREFIX + car.getUserId();//Map<String,Car> 键(存储bookId) 值存储购物车某一个商品的信息Map<String, Car> CarMap = null;boolean flag = true;//获得Redis中以存储的当前用户的购物车信息if (opsForHash.hasKey(CAR_KEY, userCarKey)) {//存在当前用户的购物车信息，那么获取原有的数据String carMapJson = opsForHash.get(CAR_KEY, userCarKey);CarMap = JSONObject.parseObject(carMapJson, new TypeReference<Map<String, Car>>() {});//检测当前购物车信息中是否包含新添加上的商品，如果包含则更新数量，如果不包含才新增if (CarMap.containsKey(car.getBookId())) {//获取原先商品的数量Integer BeforeNumber = CarMap.get(car.getBookId()).getNumber();log.info("BeforeNumber==============>{}", BeforeNumber);Integer nowNumber = car.getNumber(); //前端传过来现在的log.info("nowNumber==============>{}", nowNumber);CarMap.get(car.getBookId()).setNumber(BeforeNumber + nowNumber);flag = false; //存在商品//修改//包含才新增 图书的数量 在原有的基础上新增图书的数量} else {//新增//如果不包含当前商品信息 那么直接将商品添加到购物车信息当中CarMap.put(car.getBookId(), car);}} else {/* 新增** 当前的用户的购物车信息不存在* 首先把其添加的商品首先存储到CarMap中* */CarMap = new HashMap<>();CarMap.put(car.getBookId(), car);}//最后将其存入redis当中opsForHash.put(CAR_KEY, userCarKey, JSONObject.toJSONString(CarMap));if (flag){//新增stringRedisTemplate.convertAndSend(ChannelEnum.INSERTED.name(), JSONObject.toJSONString(CarMap.get(car.getBookId())));}else {//修改stringRedisTemplate.convertAndSend(ChannelEnum.UPDATED.name(), JSONObject.toJSONString(CarMap.get(car.getBookId())));}}@Overridepublic Collection<Car> getCarList(String userId) {//这里存储的时候采用Redis当中的hash存储HashOperations<String, String, String> opsForHash = stringRedisTemplate.opsForHash();String userCarKey = USER_CAR_HASH_FIELD_PREFIX + userId;String jsonStr = opsForHash.get(CAR_KEY, userCarKey);Map<String,Car> CarMap = JSONObject.parseObject(jsonStr, Map.class);return CarMap.values();}@Overridepublic void updataCount(String bookId, int number, String userId) {//这里存储的时候采用Redis当中的hash存储HashOperations<String, String, String> opsForHash = stringRedisTemplate.opsForHash();String userCarKey = USER_CAR_HASH_FIELD_PREFIX + userId;String jsonStr = opsForHash.get(CAR_KEY, userCarKey);Map<String,Car> CarMap = JSONObject.parseObject(jsonStr, new TypeReference<Map<String, Car>>() {});if (!CarMap.containsKey(bookId)){ //不包含return;}Car car = CarMap.get(bookId);car.setNumber(number);//最后将其存入redis当中opsForHash.put(CAR_KEY, userCarKey, JSONObject.toJSONString(CarMap));stringRedisTemplate.convertAndSend(ChannelEnum.UPDATED.name(), JSONObject.toJSONString(CarMap.get(car.getBookId())));}@Overridepublic void delCar(String[] bookIds, String userId) {//获得操作RedisHash的对象HashOperations<String, String, String> forHash = stringRedisTemplate.opsForHash();String userCarKey = USER_CAR_HASH_FIELD_PREFIX+userId;List<String[]> list = new ArrayList<>();//从redis中获取用户对应的购物车数据String carJsonStr = forHash.get(CAR_KEY, userCarKey);//修改指定商品的数量Map<String,Car> carMap = JSONObject.parseObject(carJsonStr, new TypeReference<Map<String,Car>>() {});for(String bookId : bookIds){carMap.remove(bookId);}//将修改后的数据重新添加到redis中forHash.put(CAR_KEY,userCarKey,JSONObject.toJSONString(carMap));list.add(bookIds);list.add(new String[]{userId});stringRedisTemplate.convertAndSend(ChannelEnum.DELETED.name(), JSONObject.toJSONString(list));}
}上述的两段代码中
第二段代码中stringRedisTemplate.convertAndSend();就是发送消息的，其中参数1是发送消息的名称，参数2是发送消息的内容
第一段代码中的这个就是监听到后接收到的消息，其中参数1{当中的onMessage方法的参数1Message为发送消息的内容，参数2pattern是发送消息的名称} 参数2为监听指定的消息名称（这个要和stringRedisTemplate.convertAndSend()中参数1的要保持一致）
listenerContainer.addMessageListener(new MessageListener() {@Overridepublic void onMessage(Message message, byte[] pattern) {}}, new ChannelTopic(ChannelEnum.INSERTED.name()));
 + 思维导图)
