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使用Java代碼實(shí)現(xiàn)Redis和數(shù)據(jù)庫(kù)數(shù)據(jù)同步

更新時(shí)間：2024年06月03日 08:39:38 作者：浮夸的小白菜

這篇文章主要介紹了使用Java代碼實(shí)現(xiàn)Redis和數(shù)據(jù)庫(kù)數(shù)據(jù)同步問(wèn)題,文中通過(guò)代碼示例給大家講解的非常詳細(xì),對(duì)大家的學(xué)習(xí)或工作有一定的幫助,需要的朋友可以參考下

這里我用到了Redis當(dāng)中的發(fā)布訂閱模式實(shí)現(xiàn)(JAVA代碼實(shí)現(xiàn))

先看圖示

下面為代碼實(shí)現(xiàn)

首先將RedisMessageListenerContainer交給Spring管理.

@Configuration
public class redisConfig {
    @Autowired
    RedisConnectionFactory redisConnectionFactory;
 
    @Autowired
    @Qualifier("carServiceDb")
    private CarService carService;//操作數(shù)據(jù)庫(kù)
    @Bean
    public RedisMessageListenerContainer listenerContainer(){
        //創(chuàng)建一個(gè)Redis消息監(jiān)聽(tīng)器容器對(duì)象
        RedisMessageListenerContainer listenerContainer = new RedisMessageListenerContainer();
         //設(shè)置Redis連接工廠(chǎng)對(duì)象
        listenerContainer.setConnectionFactory(redisConnectionFactory);
 
        //向監(jiān)聽(tīng)器容器中添加一個(gè)監(jiān)聽(tīng)器，該監(jiān)聽(tīng)器的主題為INSERTED
        listenerContainer.addMessageListener(new MessageListener() {
            @Override
            public 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()));
 
        //向監(jiān)聽(tīng)器容器中添加一個(gè)監(jiān)聽(tīng)器，該監(jiān)聽(tīng)器的主題為UPDATED
        listenerContainer.addMessageListener(new MessageListener() {
            @Override
            public 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()));
 
        //向監(jiān)聽(tīng)器容器中添加一個(gè)監(jiān)聽(tīng)器，該監(jiān)聽(tīng)器的主題為DELETED
        listenerContainer.addMessageListener(new MessageListener() {
            @Override
            public 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;
    }
}

下面代碼中的 stringRedisTemplate.convertAndSend();就是發(fā)送消息的，其中參數(shù)1是發(fā)送消息的名稱(chēng)，參數(shù)2是發(fā)送消息的內(nèi)容

@Service("carService")
@Slf4j
public class CarServiceImpl extends ServiceImpl<CarMapper, Car> implements CarService {
    //購(gòu)物車(chē)hash的Key
    public static final String CAR_KEY = "carKey";
    //hash購(gòu)物車(chē)中field的前綴
    public static final String USER_CAR_HASH_FIELD_PREFIX = "car::";
    @Resource
    private StringRedisTemplate stringRedisTemplate;
 
    /**
     * 這里存儲(chǔ)的時(shí)候采用Redis當(dāng)中的hash存儲(chǔ)
     *
     * @param car
     */
    @Override
    @Synchronized
    public void addCar(Car car) {
        //這里存儲(chǔ)的時(shí)候采用Redis當(dāng)中的hash存儲(chǔ)
        HashOperations<String, String, String> opsForHash = stringRedisTemplate.opsForHash();
 
        //這里field為CAR_HASH_FIELD
        String userCarKey = USER_CAR_HASH_FIELD_PREFIX + car.getUserId();
 
        //Map<String,Car>  鍵(存儲(chǔ)bookId)  值存儲(chǔ)購(gòu)物車(chē)某一個(gè)商品的信息
        Map<String, Car> CarMap = null;
        boolean flag = true;
        //獲得Redis中以存儲(chǔ)的當(dāng)前用戶(hù)的購(gòu)物車(chē)信息
        if (opsForHash.hasKey(CAR_KEY, userCarKey)) {
            //存在當(dāng)前用戶(hù)的購(gòu)物車(chē)信息，那么獲取原有的數(shù)據(jù)
            String carMapJson = opsForHash.get(CAR_KEY, userCarKey);
 
            CarMap = JSONObject.parseObject(carMapJson, new TypeReference<Map<String, Car>>() {
            });
 
            //檢測(cè)當(dāng)前購(gòu)物車(chē)信息中是否包含新添加上的商品，如果包含則更新數(shù)量，如果不包含才新增
            if (CarMap.containsKey(car.getBookId())) {
                //獲取原先商品的數(shù)量
                Integer BeforeNumber = CarMap.get(car.getBookId()).getNumber();
                log.info("BeforeNumber==============>{}", BeforeNumber);
                Integer nowNumber = car.getNumber(); //前端傳過(guò)來(lái)現(xiàn)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 圖書(shū)的數(shù)量 在原有的基礎(chǔ)上新增圖書(shū)的數(shù)量
            } else {
                //新增
                //如果不包含當(dāng)前商品信息 那么直接將商品添加到購(gòu)物車(chē)信息當(dāng)中
                CarMap.put(car.getBookId(), car);
            }
        } else {
            /*   新增
             *
             * 當(dāng)前的用戶(hù)的購(gòu)物車(chē)信息不存在
             *       首先把其添加的商品首先存儲(chǔ)到CarMap中
             * */
            CarMap = new HashMap<>();
            CarMap.put(car.getBookId(), car);
        }
 
        //最后將其存入redis當(dāng)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())));
        }
    }
 
    @Override
    public Collection<Car> getCarList(String userId) {
        //這里存儲(chǔ)的時(shí)候采用Redis當(dāng)中的hash存儲(chǔ)
        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();
    }
 
    @Override
    public void updataCount(String bookId, int number, String userId) {
        //這里存儲(chǔ)的時(shí)候采用Redis當(dāng)中的hash存儲(chǔ)
        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);
 
        //最后將其存入redis當(dāng)中
        opsForHash.put(CAR_KEY, userCarKey, JSONObject.toJSONString(CarMap));
        stringRedisTemplate.convertAndSend(ChannelEnum.UPDATED.name(), JSONObject.toJSONString(CarMap.get(car.getBookId())));
 
    }
 
    @Override
    public void delCar(String[] bookIds, String userId) {
        //獲得操作RedisHash的對(duì)象
        HashOperations<String, String, String> forHash = stringRedisTemplate.opsForHash();
        String userCarKey = USER_CAR_HASH_FIELD_PREFIX+userId;
        List<String[]> list = new ArrayList<>();
        //從redis中獲取用戶(hù)對(duì)應(yīng)的購(gòu)物車(chē)數(shù)據(jù)
        String carJsonStr = forHash.get(CAR_KEY, userCarKey);
        //修改指定商品的數(shù)量
        Map<String,Car> carMap = JSONObject.parseObject(carJsonStr, new TypeReference<Map<String,Car>>() {
        });
        for(String bookId : bookIds){
            carMap.remove(bookId);
        }
 
        //將修改后的數(shù)據(jù)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));
    }
}

上述的兩段代碼中

第二段代碼中stringRedisTemplate.convertAndSend();就是發(fā)送消息的，其中參數(shù)1是發(fā)送消息的名稱(chēng)，參數(shù)2是發(fā)送消息的內(nèi)容

第一段代碼中的這個(gè)就是監(jiān)聽(tīng)到后接收到的消息，其中參數(shù)1{當(dāng)中的onMessage方法的參數(shù)1Message為發(fā)送消息的內(nèi)容，參數(shù)2pattern是發(fā)送消息的名稱(chēng)} 參數(shù)2為監(jiān)聽(tīng)指定的消息名稱(chēng)（這個(gè)要和stringRedisTemplate.convertAndSend()中參數(shù)1的要保持一致）

listenerContainer.addMessageListener(new MessageListener() {
            @Override
            public void onMessage(Message message, byte[] pattern) {
                
            }
        }, new ChannelTopic(ChannelEnum.INSERTED.name()));

以上就是使用Java代碼實(shí)現(xiàn)Redis和數(shù)據(jù)庫(kù)數(shù)據(jù)同步的詳細(xì)內(nèi)容，更多關(guān)于Java Redis和數(shù)據(jù)庫(kù)同步的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章！

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