日本免费高清视频-国产福利视频导航-黄色在线播放国产-天天操天天操天天操天天操|www.shdianci.com

學(xué)無(wú)先后，達(dá)者為師

網(wǎng)站首頁(yè) 編程語(yǔ)言 正文

手把手教你用Redis?實(shí)現(xiàn)點(diǎn)贊功能并且與數(shù)據(jù)庫(kù)同步_Redis

作者：泊船夜雪，他年可期 ? 更新時(shí)間： 2022-07-12 編程語(yǔ)言

一、Redis 緩存設(shè)計(jì)及實(shí)現(xiàn)

Linux下安裝Redis或者Docker下安裝Redis并且啟動(dòng)(redis-server)

SpringBoot整合Redis

1.在 pom.xml 中引入依賴

<dependency>    
    <groupId>org.springframework.boot</groupId>    
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2.在啟動(dòng)類上添加注釋 @EnableCaching

3.編寫 Redis 配置類 RedisConfig

@Configuration
public class RedisConfig {    
    @Bean    
    @ConditionalOnMissingBean(name = "redisTemplate")    
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory)throws UnknownHostException {
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer= new Jackson2JsonRedisSerializer<Object>(Object.class);        
        ObjectMapper om = new ObjectMapper();        
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
        template.setConnectionFactory(redisConnectionFactory);
        template.setKeySerializer(jackson2JsonRedisSerializer);
        template.setValueSerializer(jackson2JsonRedisSerializer);
        template.setHashKeySerializer(jackson2JsonRedisSerializer);
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
        return template;    
      }    
    @Bean    
    @ConditionalOnMissingBean(StringRedisTemplate.class)    
    public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory)throws UnknownHostException {
        StringRedisTemplate template = new StringRedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);        
    return template;  
    }
}

二、點(diǎn)贊數(shù)據(jù)在 Redis 中的存儲(chǔ)格式

用 Redis 存儲(chǔ)兩種數(shù)據(jù)：

  • 一種是記錄點(diǎn)贊人、被點(diǎn)贊人、點(diǎn)贊狀態(tài)的數(shù)據(jù)
  • 一種是每個(gè)用戶被點(diǎn)贊了多少次，做個(gè)簡(jiǎn)單的計(jì)數(shù)

由于需要記錄點(diǎn)贊人和被點(diǎn)贊人，還有點(diǎn)贊狀態(tài)（點(diǎn)贊、取消點(diǎn)贊），還要固定時(shí)間間隔取出 Redis 中所有點(diǎn)贊數(shù)據(jù)，所以 Redis 數(shù)據(jù)格式中 Hash 最合適。

因?yàn)?Hash 里的數(shù)據(jù)都是存在一個(gè)鍵里，可以通過這個(gè)鍵很方便的把所有的點(diǎn)贊數(shù)據(jù)都取出。這個(gè)鍵里面的數(shù)據(jù)還可以存成鍵值對(duì)的形式，方便存入點(diǎn)贊人、被點(diǎn)贊人和點(diǎn)贊狀態(tài)。

設(shè)點(diǎn)贊人的 id 為 giveLikeId，被點(diǎn)贊人的 id 為 likeUserId ，點(diǎn)贊時(shí)狀態(tài)為 1，取消點(diǎn)贊狀態(tài)為 0。將點(diǎn)贊人 id 和被點(diǎn)贊人 id 作為鍵，兩個(gè) id 中間用 :: 隔開，點(diǎn)贊狀態(tài)作為值。

類似于這樣：

在這里插入圖片描述

在service層操作Redis

public interface RedisService {    
/**     
 * 點(diǎn)贊。狀態(tài)為1     
 * @param likedUserId     
 * @param giveLikeId     
 */    
void saveLiked2Redis(String likedUserId, String giveLikeId);    
/**     
 * 取消點(diǎn)贊。將狀態(tài)改變?yōu)?     
 * @param likedUserId     
 * @param giveLikeId     
 */    
void unlikeFromRedis(String likedUserId, String giveLikeId);    
/**     
 * 從Redis中刪除一條點(diǎn)贊數(shù)據(jù)     
 * @param likedUserId     
 * @param giveLikeId     
 */    
void deleteLikedFromRedis(String likedUserId, String giveLikeId);    
/**     
 * 該用戶的點(diǎn)贊數(shù)加1     
 * @param likedUserId     
 */    
void incrementLikedCount(String likedUserId);    
/**     
 * 該用戶的點(diǎn)贊數(shù)減1     
 * @param likedUserId     
 */    
void decrementLikedCount(String likedUserId);    
/**     
 * 獲取Redis中存儲(chǔ)的所有點(diǎn)贊數(shù)據(jù)     
 * @return     
 */    
List<UserLike> getLikedDataFromRedis();    
/**     
 * 獲取Redis中存儲(chǔ)的所有點(diǎn)贊數(shù)量     
 * @return     
 */    
List<LikedCountDTO> getLikedCountFromRedis();}

實(shí)現(xiàn)類 RedisServiceImpl ：

@Service
@Slf4j
public class RedisServiceImpl implements RedisService {    
    @Autowired    
    RedisTemplate redisTemplate;    
    @Autowired    
    LikedService likedService;    
  @Override    
  public void saveLiked2Redis(String likedUserId, String giveLikeId) {          
      String key = RedisKeyUtils.getLikedKey(likedUserId, giveLikeId);            
      redisTemplate.opsForHash().put(RedisKeyUtils.MAP_USER_LIKED, 
      key, LikedStatusEnum.LIKE.getCode());    
      }    
  @Override    
  public void unlikeFromRedis(String likedUserId, String giveLikeId) {          
      String key = RedisKeyUtils.getLikedKey(likedUserId, giveLikeId);            
      redisTemplate.opsForHash().put(RedisKeyUtils.MAP_USER_LIKED, 
      key, LikedStatusEnum.UNLIKE.getCode());    
      }    
  @Override    
  public void deleteLikedFromRedis(String likedUserId, String giveLikeId) {    
      String key = RedisKeyUtils.getLikedKey(likedUserId, giveLikeId);            
      redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_USER_LIKED, key);   
      }    
  @Override    
  public void incrementLikedCount(String likedUserId) {
      redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_USER_LIKED_COUNT,likedUserId,1);    
 }    
 @Override
 public void decrementLikedCount(String likedUserId) {        
     redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_USER_LIKED_COUNT,likedUserId,-1);    
 }    
 @Override
 public List<UserLike> getLikedDataFromRedis() {                
     Cursor<Map.Entry<Object, Object>> cursor =redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_USER_LIKED, ScanOptions.NONE);        
     List<UserLike> list = new ArrayList<>();
     while (cursor.hasNext()){
         Map.Entry<Object, Object> entry = cursor.next();
         String key = (String) entry.getKey();
         //分離出 likedUserId，giveLikeId
         String[] split = key.split("::");
         String likedUserId = split[0];
         String giveLikeId = split[1];
         Integer value = (Integer) entry.getValue();
         //組裝成 UserLike 對(duì)象
         UserLike userLike = new UserLike(likedUserId, giveLikeId, value);
         list.add(userLike);
         //存到 list 后從 Redis 中刪除
         redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_USER_LIKED, key);        
         }        return list;    
    }   
 @Override    
 public List<LikedCountDTO> getLikedCountFromRedis() {
     Cursor<Map.Entry<Object, Object>> cursor =    redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_USER_LIKED_COUNT,  ScanOptions.NONE);
     List<LikedCountDTO> list = new ArrayList<>();
     while (cursor.hasNext()){
        Map.Entry<Object, Object> map = cursor.next();
        //將點(diǎn)贊數(shù)量存儲(chǔ)在 LikedCountDT
          String key = (String)map.getKey(); 
        LikedCountDTO dto = new LikedCountDTO(key, (Integer)    map.getValue());
        list.add(dto);
        //從Redis中刪除這條記錄 
          redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_USER_LIKED_COUNT, key);        
        }        
    return list;    
    }
}

RedisKeyUtils, 用于根據(jù)一定規(guī)則生成 key

public class RedisKeyUtils {

    //保存用戶點(diǎn)贊數(shù)據(jù)的key
    public static final String MAP_USER_LIKED = "MAP_USER_LIKED";
    //保存用戶被點(diǎn)贊數(shù)量的key
    public static final String MAP_USER_LIKED_COUNT = "MAP_USER_LIKED_COUNT";

    /**
     * 拼接被點(diǎn)贊的用戶id和點(diǎn)贊的人的id作為key。格式 001::1006
     * @param likedUserId 被點(diǎn)贊的人id
     * @param giveLikeId 點(diǎn)贊的人的id
     * @return
     */
    public static String getLikedKey(String likedUserId, String giveLikeId){
        StringBuilder builder = new StringBuilder();
        builder.append(likedUserId);
        builder.append("::");
        builder.append(giveLikeId);
        return builder.toString();
    }
}

LikedStatusEnum 用戶點(diǎn)贊狀態(tài)的枚舉類

/**
 * 用戶點(diǎn)贊的狀態(tài)
 */
@Getter
public enum LikedStatusEnum {
    LIKE(1, "點(diǎn)贊"),
    UNLIKE(0, "取消點(diǎn)贊/未點(diǎn)贊"),
    ;

    private Integer code;

    private String msg;

    LikedStatusEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
}

三、數(shù)據(jù)庫(kù)設(shè)計(jì)

數(shù)據(jù)庫(kù)表中至少要包含三個(gè)字段：被點(diǎn)贊用戶 id，點(diǎn)贊用戶 id，點(diǎn)贊狀態(tài)。再加上主鍵 id，創(chuàng)建時(shí)間，修改時(shí)間就行了。

create table `user_like`(
    `id` int not null auto_increment,
    `liked_user_id` varchar(32) not null comment '被點(diǎn)贊的用戶id',
    `give_liked_id` varchar(32) not null comment '點(diǎn)贊的用戶id',
    `status` tinyint(1) default '1' comment '點(diǎn)贊狀態(tài)，0取消，1點(diǎn)贊',
    `create_time` timestamp not null default current_timestamp comment '創(chuàng)建   時(shí)間',
  `update_time` timestamp not null default current_timestamp on update    current_timestamp comment '修改時(shí)間',
    primary key(`id`),
    INDEX `liked_user_id`(`liked_user_id`),
    INDEX `give_liked_id`(`give_liked_id`)
) comment '用戶點(diǎn)贊表';

對(duì)應(yīng)的對(duì)象 UserLike

/**
 * 用戶點(diǎn)贊表
 */
@Entity
@Data
public class UserLike {

    //主鍵id
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    //被點(diǎn)贊的用戶的id
    private String likedUserId;

    //點(diǎn)贊的用戶的id
    private String giveLikedId;

    //點(diǎn)贊的狀態(tài).默認(rèn)未點(diǎn)贊
    private Integer status = LikedStatusEnum.UNLIKE.getCode();

    public UserLike() {
    }

    public UserLike(String likedUserId, String giveLikedId, Integer status) {
        this.likedUserId = likedUserId;
        this.giveLikedId = giveLikedId;
        this.status = status;
    }
}

在service層操作數(shù)據(jù)庫(kù)

public interface LikedService {

    /**
     * 保存點(diǎn)贊記錄
     * @param userLike
     * @return
     */
    UserLike save(UserLike userLike);

    /**
     * 批量保存或修改
     * @param list
     */
    List<UserLike> saveAll(List<UserLike> list);


    /**
     * 根據(jù)被點(diǎn)贊人的id查詢點(diǎn)贊列表（即查詢都誰(shuí)給這個(gè)人點(diǎn)贊過）
     * @param likedUserId 被點(diǎn)贊人的id
     * @param pageable
     * @return
     */
    Page<UserLike> getLikedListByLikedUserId(String likedUserId, Pageable pageable);

    /**
     * 根據(jù)點(diǎn)贊人的id查詢點(diǎn)贊列表（即查詢這個(gè)人都給誰(shuí)點(diǎn)贊過）
     * @param giveLikedId
     * @param pageable
     * @return
     */
    Page<UserLike> getLikedListByGiveLikedId(String giveLikedId, Pageable pageable);

    /**
     * 通過被點(diǎn)贊人和點(diǎn)贊人id查詢是否存在點(diǎn)贊記錄
     * @param likedUserId
     * @param giveLikedId
     * @return
     */
    UserLike getByLikedUserIdAndGiveLikedId(String likedUserId, String giveLikedId);

    /**
     * 將Redis里的點(diǎn)贊數(shù)據(jù)存入數(shù)據(jù)庫(kù)中
     */
    void transLikedFromRedis2DB();

    /**
     * 將Redis中的點(diǎn)贊數(shù)量數(shù)據(jù)存入數(shù)據(jù)庫(kù)
     */
    void transLikedCountFromRedis2DB();

}

LikedServiceImpl 實(shí)現(xiàn)類

@Service
@Slf4j
public class LikedServiceImpl implements LikedService {

    @Autowired
    UserLikeRepository likeRepository;

    @Autowired
    RedisService redisService;

    @Autowired
    UserService userService;

    @Override
    @Transactional
    public UserLike save(UserLike userLike) {
        return likeRepository.save(userLike);
    }

    @Override
    @Transactional
    public List<UserLike> saveAll(List<UserLike> list) {
        return likeRepository.saveAll(list);
    }

    @Override
    public Page<UserLike> getLikedListByLikedUserId(String likedUserId, Pageable pageable) {
        return likeRepository.findByLikedUserIdAndStatus(likedUserId, LikedStatusEnum.LIKE.getCode(), pageable);
    }

    @Override
    public Page<UserLike> getLikedListByGiveLikedId(String giveLikedId, Pageable pageable) {
        return likeRepository.findByGiveLikedIdAndStatus(giveLikedId, LikedStatusEnum.LIKE.getCode(), pageable);
    }

    @Override
    public UserLike getByLikedUserIdAndGiveLikedId(String likedUserId, String giveLikedId) {
        return likeRepository.findByLikedUserIdAndLikedPostId(likedUserId, giveLikedId);
    }

    @Override
    @Transactional
    public void transLikedFromRedis2DB() {
        List<UserLike> list = redisService.getLikedDataFromRedis();
        for (UserLike like : list) {
            UserLike ul = getByLikedUserIdAndGiveLikedId(like.getLikedUserId(), like.getGiveLikedId());
            if (ul == null){
                //沒有記錄，直接存入
                save(like);
            }else{
                //有記錄，需要更新
                ul.setStatus(like.getStatus());
                save(ul);
            }
        }
    }

    @Override
    @Transactional
    public void transLikedCountFromRedis2DB() {
        List<LikedCountDTO> list = redisService.getLikedCountFromRedis();
        for (LikedCountDTO dto : list) {
            UserInfo user = userService.findById(dto.getId());
            //點(diǎn)贊數(shù)量屬于無(wú)關(guān)緊要的操作，出錯(cuò)無(wú)需拋異常
            if (user != null){
                Integer likeNum = user.getLikeNum() + dto.getCount();
                user.setLikeNum(likeNum);
                //更新點(diǎn)贊數(shù)量
                userService.updateInfo(user);
            }
        }
    }
}

四、開啟定時(shí)任務(wù)持久化存儲(chǔ)到數(shù)據(jù)庫(kù)

這里使用的是定時(shí)任務(wù) Quartz框架

1、 添加依賴

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-quartz</artifactId>
</dependency>

2、 編寫配置文件

@Configuration
public class QuartzConfig {

    private static final String LIKE_TASK_IDENTITY = "LikeTaskQuartz";

    @Bean
    public JobDetail quartzDetail(){
        return JobBuilder.newJob(LikeTask.class).withIdentity(LIKE_TASK_IDENTITY).storeDurably().build();
    }

    @Bean
    public Trigger quartzTrigger(){
        SimpleScheduleBuilder scheduleBuilder = SimpleScheduleBuilder.simpleSchedule()
                        .withIntervalInSeconds(10)  //設(shè)置時(shí)間周期單位秒
                .withIntervalInHours(2)  //兩個(gè)小時(shí)執(zhí)行一次
                .repeatForever();
        return TriggerBuilder.newTrigger().forJob(quartzDetail())
                .withIdentity(LIKE_TASK_IDENTITY)
                .withSchedule(scheduleBuilder)
                .build();
    }
}

3、 編寫執(zhí)行任務(wù)的類繼承自 QuartzJobBean

/**
 * 點(diǎn)贊的定時(shí)任務(wù)
 */
@Slf4j
public class LikeTask extends QuartzJobBean {

    @Autowired
    LikedService likedService;

    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    @Override
    protected void executeInternal(JobExecutionContext jobExecutionContext) throws JobExecutionException {

        log.info("LikeTask-------- {}", sdf.format(new Date()));

        //將 Redis 里的點(diǎn)贊信息同步到數(shù)據(jù)庫(kù)里
        likedService.transLikedFromRedis2DB();
        likedService.transLikedCountFromRedis2DB();
    }
}

在定時(shí)任務(wù)中直接調(diào)用 LikedService 封裝的方法完成數(shù)據(jù)同步。

五、注意事項(xiàng)

1.點(diǎn)贊 / 取消點(diǎn)贊 跟 點(diǎn)贊數(shù) +1/ -1 應(yīng)該保證是原子操作 ,不然出現(xiàn)并發(fā)問題就會(huì)有兩條重復(fù)的點(diǎn)贊記錄 , 所以要給整個(gè)原子操作加鎖 。

2.同時(shí)需要在 Spring Boot 的系統(tǒng)關(guān)閉鉤子函數(shù)中補(bǔ)充同步 redis 中點(diǎn)贊數(shù)據(jù)到 mysql 中的過程 . 不然有可能出現(xiàn)距離上一次同步 1 小時(shí) 59 分的時(shí)候服務(wù)器更新 , 把整整兩小時(shí)的點(diǎn)贊數(shù)據(jù)都給清空了 。

原文鏈接：https://blog.csdn.net/Greenarrow961224/article/details/110918566

欄目分類
最近更新