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          Redis是如何實(shí)現(xiàn)點(diǎn)贊、取消點(diǎn)贊的?

          共 16809字,需瀏覽 34分鐘

           ·

          2021-01-30 11:01


          作者:solocoder

          juejin.im/post/5bdc257e6fb9a049ba410098


          本文基于 SpringCloud, 用戶發(fā)起點(diǎn)贊、取消點(diǎn)贊后先存入 Redis 中,再每隔兩小時從 Redis 讀取點(diǎn)贊數(shù)據(jù)寫入數(shù)據(jù)庫中做持久化存儲。

          點(diǎn)贊功能在很多系統(tǒng)中都有,但別看功能小,想要做好需要考慮的東西還挺多的。

          點(diǎn)贊、取消點(diǎn)贊是高頻次的操作,若每次都讀寫數(shù)據(jù)庫,大量的操作會影響數(shù)據(jù)庫性能,所以需要做緩存。

          至于多久從 Redis 取一次數(shù)據(jù)存到數(shù)據(jù)庫中,根據(jù)項(xiàng)目的實(shí)際情況定吧,我是暫時設(shè)了兩個小時。

          項(xiàng)目需求需要查看都誰點(diǎn)贊了,所以要存儲每個點(diǎn)贊的點(diǎn)贊人、被點(diǎn)贊人,不能簡單的做計(jì)數(shù)。

          文章分四部分介紹:

          • Redis 緩存設(shè)計(jì)及實(shí)現(xiàn)

          • 數(shù)據(jù)庫設(shè)計(jì)

          • 數(shù)據(jù)庫操作

          • 開啟定時任務(wù)持久化存儲到數(shù)據(jù)庫

          一、Redis 緩存設(shè)計(jì)及實(shí)現(xiàn)

          1.1 Redis 安裝及運(yùn)行

          Redis 安裝請自行查閱相關(guān)教程。

          說下Docker 安裝運(yùn)行 Redis

          docker?run?-d?-p?6379:6379?redis:4.0.8

          如果已經(jīng)安裝了 Redis,打開命令行,輸入啟動 Redis 的命令

          redis-server

          1.2 Redis 與 SpringBoot 項(xiàng)目的整合

          1.在 pom.xml 中引入依賴

          <dependency>
          ????<groupId>org.springframework.bootgroupId>
          ????<artifactId>spring-boot-starter-data-redisartifactId>
          dependency>

          2.在啟動類上添加注釋 @EnableCaching

          @SpringBootApplication@EnableDiscoveryClient@EnableSwagger2@EnableFeignClients(basePackages = "com.solo.coderiver.project.client")@EnableCachingpublic class UserApplication {
          public static void main(String[] args) { SpringApplication.run(UserApplication.class, args); }}

          3.編寫 Redis 配置類 RedisConfig

          import com.fasterxml.jackson.annotation.JsonAutoDetect;import com.fasterxml.jackson.annotation.PropertyAccessor;import com.fasterxml.jackson.databind.ObjectMapper;import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.redis.connection.RedisConnectionFactory;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.StringRedisTemplate;import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
          import java.net.UnknownHostException;

          @Configurationpublic class RedisConfig {
          @Bean @ConditionalOnMissingBean(name = "redisTemplate") public RedisTemplate redisTemplate( RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
          Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class); ObjectMapper om = new ObjectMapper(); om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY); om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL); jackson2JsonRedisSerializer.setObjectMapper(om);
          RedisTemplate template = new RedisTemplate(); 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; }}

          至此 Redis 在 SpringBoot 項(xiàng)目中的配置已經(jīng)完成,可以愉快的使用了。

          1.3 Redis 的數(shù)據(jù)結(jié)構(gòu)類型

          Redis 可以存儲鍵與5種不同數(shù)據(jù)結(jié)構(gòu)類型之間的映射,這5種數(shù)據(jù)結(jié)構(gòu)類型分別為String(字符串)、List(列表)、Set(集合)、Hash(散列)和 Zset(有序集合)。

          下面來對這5種數(shù)據(jù)結(jié)構(gòu)類型作簡單的介紹:

          1.4 點(diǎn)贊數(shù)據(jù)在 Redis 中的存儲格式

          用 Redis 存儲兩種數(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),另一種是每個用戶被點(diǎn)贊了多少次,做個簡單的計(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),還要固定時間間隔取出 Redis 中所有點(diǎn)贊數(shù)據(jù),分析了下 Redis 數(shù)據(jù)格式中 Hash 最合適。

          因?yàn)?Hash 里的數(shù)據(jù)都是存在一個鍵里,可以通過這個鍵很方便的把所有的點(diǎn)贊數(shù)據(jù)都取出。這個鍵里面的數(shù)據(jù)還可以存成鍵值對的形式,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 likedPostId,被點(diǎn)贊人的 id 為 likedUserId ,點(diǎn)贊時狀態(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 id 中間用 :: 隔開,點(diǎn)贊狀態(tài)作為值。

          所以如果用戶點(diǎn)贊,存儲的鍵為:likedUserId::likedPostId,對應(yīng)的值為 1 。取消點(diǎn)贊,存儲的鍵為:likedUserId::likedPostId,對應(yīng)的值為 0 。取數(shù)據(jù)時把鍵用 :: 切開就得到了兩個id,也很方便。

          在可視化工具 RDM 中看到的是這樣子

          1.5 操作 Redis

          將具體操作方法封裝到了 RedisService 接口里

          RedisService.java

          import com.solo.coderiver.user.dataobject.UserLike;import com.solo.coderiver.user.dto.LikedCountDTO;
          import java.util.List;
          public interface RedisService {
          /** * 點(diǎn)贊。狀態(tài)為1 * @param likedUserId * @param likedPostId */ void saveLiked2Redis(String likedUserId, String likedPostId);
          /** * 取消點(diǎn)贊。將狀態(tài)改變?yōu)? * @param likedUserId * @param likedPostId */ void unlikeFromRedis(String likedUserId, String likedPostId);
          /** * 從Redis中刪除一條點(diǎn)贊數(shù)據(jù) * @param likedUserId * @param likedPostId */ void deleteLikedFromRedis(String likedUserId, String likedPostId);
          /** * 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中存儲的所有點(diǎn)贊數(shù)據(jù) * @return */ List getLikedDataFromRedis();
          /** * 獲取Redis中存儲的所有點(diǎn)贊數(shù)量 * @return */ List getLikedCountFromRedis();
          }

          實(shí)現(xiàn)類 RedisServiceImpl.java

          import com.solo.coderiver.user.dataobject.UserLike;import com.solo.coderiver.user.dto.LikedCountDTO;import com.solo.coderiver.user.enums.LikedStatusEnum;import com.solo.coderiver.user.service.LikedService;import com.solo.coderiver.user.service.RedisService;import com.solo.coderiver.user.utils.RedisKeyUtils;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.redis.core.Cursor;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.ScanOptions;import org.springframework.stereotype.Service;
          import java.util.ArrayList;import java.util.List;import java.util.Map;
          @Service@Slf4jpublic class RedisServiceImpl implements RedisService {
          @Autowired RedisTemplate redisTemplate;
          @Autowired LikedService likedService;
          @Override public void saveLiked2Redis(String likedUserId, String likedPostId) { String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId); redisTemplate.opsForHash().put(RedisKeyUtils.MAP_KEY_USER_LIKED, key, LikedStatusEnum.LIKE.getCode()); }
          @Override public void unlikeFromRedis(String likedUserId, String likedPostId) { String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId); redisTemplate.opsForHash().put(RedisKeyUtils.MAP_KEY_USER_LIKED, key, LikedStatusEnum.UNLIKE.getCode()); }
          @Override public void deleteLikedFromRedis(String likedUserId, String likedPostId) { String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId); redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key); }
          @Override public void incrementLikedCount(String likedUserId) { redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, 1); }
          @Override public void decrementLikedCount(String likedUserId) { redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, -1); }
          @Override public List getLikedDataFromRedis() { CursorObject, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED, ScanOptions.NONE); List list = new ArrayList<>(); while (cursor.hasNext()){ Map.Entry<Object, Object> entry = cursor.next(); String key = (String) entry.getKey(); //分離出 likedUserId,likedPostId String[] split = key.split("::"); String likedUserId = split[0]; String likedPostId = split[1]; Integer value = (Integer) entry.getValue();
          //組裝成 UserLike 對象 UserLike userLike = new UserLike(likedUserId, likedPostId, value); list.add(userLike);
          //存到 list 后從 Redis 中刪除 redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key); }
          return list; }
          @Override public List getLikedCountFromRedis() { CursorObject, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, ScanOptions.NONE); List list = new ArrayList<>(); while (cursor.hasNext()){ Map.Entry<Object, Object> map = cursor.next(); //將點(diǎn)贊數(shù)量存儲在 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_KEY_USER_LIKED_COUNT, key); } return list; }}

          用到的工具類和枚舉類

          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_KEY_USER_LIKED = "MAP_USER_LIKED"; //保存用戶被點(diǎn)贊數(shù)量的key public static final String MAP_KEY_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 222222::333333 * @param likedUserId 被點(diǎn)贊的人id * @param likedPostId 點(diǎn)贊的人的id * @return */ public static String getLikedKey(String likedUserId, String likedPostId){ StringBuilder builder = new StringBuilder(); builder.append(likedUserId); builder.append("::"); builder.append(likedPostId); return builder.toString(); }}

          LikedStatusEnum 用戶點(diǎn)贊狀態(tài)的枚舉類

          package com.solo.coderiver.user.enums;
          import lombok.Getter;
          /** * 用戶點(diǎn)贊的狀態(tài) */@Getterpublic 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; }}

          二、數(shù)據(jù)庫設(shè)計(jì)

          數(shù)據(jù)庫表中至少要包含三個字段: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)建時間,修改時間就行了。

          建表語句

          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',    `liked_post_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)建時間',  `update_time` timestamp not null default current_timestamp on update current_timestamp comment '修改時間',    primary key(`id`),    INDEX `liked_user_id`(`liked_user_id`),    INDEX `liked_post_id`(`liked_post_id`)) comment '用戶點(diǎn)贊表';

          對應(yīng)的對象 UserLike

          import com.solo.coderiver.user.enums.LikedStatusEnum;import lombok.Data;
          import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;
          /** * 用戶點(diǎn)贊表 */@Entity@Datapublic 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 likedPostId;
          //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 likedPostId, Integer status) { this.likedUserId = likedUserId; this.likedPostId = likedPostId; this.status = status; }}

          三、數(shù)據(jù)庫操作

          操作數(shù)據(jù)庫同樣封裝在接口中

          LikedService

          import com.solo.coderiver.user.dataobject.UserLike;import org.springframework.data.domain.Page;import org.springframework.data.domain.Pageable;
          import java.util.List;
          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 saveAll(List list);

          /** * 根據(jù)被點(diǎn)贊人的id查詢點(diǎn)贊列表(即查詢都誰給這個人點(diǎn)贊過) * @param likedUserId 被點(diǎn)贊人的id * @param pageable * @return */ Page getLikedListByLikedUserId(String likedUserId, Pageable pageable);
          /** * 根據(jù)點(diǎn)贊人的id查詢點(diǎn)贊列表(即查詢這個人都給誰點(diǎn)贊過) * @param likedPostId * @param pageable * @return */ Page getLikedListByLikedPostId(String likedPostId, 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 likedPostId * @return */ UserLike getByLikedUserIdAndLikedPostId(String likedUserId, String likedPostId);
          /** * 將Redis里的點(diǎn)贊數(shù)據(jù)存入數(shù)據(jù)庫中 */ void transLikedFromRedis2DB();
          /** * 將Redis中的點(diǎn)贊數(shù)量數(shù)據(jù)存入數(shù)據(jù)庫 */ void transLikedCountFromRedis2DB();
          }

          LikedServiceImpl 實(shí)現(xiàn)類

          import com.solo.coderiver.user.dataobject.UserInfo;import com.solo.coderiver.user.dataobject.UserLike;import com.solo.coderiver.user.dto.LikedCountDTO;import com.solo.coderiver.user.enums.LikedStatusEnum;import com.solo.coderiver.user.repository.UserLikeRepository;import com.solo.coderiver.user.service.LikedService;import com.solo.coderiver.user.service.RedisService;import com.solo.coderiver.user.service.UserService;import lombok.extern.slf4j.Slf4j;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.domain.Page;import org.springframework.data.domain.Pageable;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;
          import java.util.List;
          @Service@Slf4jpublic 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 saveAll(List list) { return likeRepository.saveAll(list); }
          @Override public Page getLikedListByLikedUserId(String likedUserId, Pageable pageable) { return likeRepository.findByLikedUserIdAndStatus(likedUserId, LikedStatusEnum.LIKE.getCode(), pageable); }
          @Override public Page getLikedListByLikedPostId(String likedPostId, Pageable pageable) { return likeRepository.findByLikedPostIdAndStatus(likedPostId, LikedStatusEnum.LIKE.getCode(), pageable); }
          @Override public UserLike getByLikedUserIdAndLikedPostId(String likedUserId, String likedPostId) { return likeRepository.findByLikedUserIdAndLikedPostId(likedUserId, likedPostId); }
          @Override @Transactional public void transLikedFromRedis2DB() { List list = redisService.getLikedDataFromRedis(); for (UserLike like : list) { UserLike ul = getByLikedUserIdAndLikedPostId(like.getLikedUserId(), like.getLikedPostId()); 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 list = redisService.getLikedCountFromRedis(); for (LikedCountDTO dto : list) { UserInfo user = userService.findById(dto.getId()); //點(diǎn)贊數(shù)量屬于無關(guān)緊要的操作,出錯無需拋異常 if (user != null){ Integer likeNum = user.getLikeNum() + dto.getCount(); user.setLikeNum(likeNum); //更新點(diǎn)贊數(shù)量 userService.updateInfo(user); } } }}

          數(shù)據(jù)庫的操作就這些,主要還是增刪改查。

          四、開啟定時任務(wù)持久化存儲到數(shù)據(jù)庫

          定時任務(wù) Quartz 很強(qiáng)大,就用它了。

          Quartz 使用步驟:

          1.添加依賴

          <dependency>    <groupId>org.springframework.bootgroupId>    <artifactId>spring-boot-starter-quartzartifactId>dependency>

          2.編寫配置文件

          package com.solo.coderiver.user.config;
          import com.solo.coderiver.user.task.LikeTask;import org.quartz.*;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;
          @Configurationpublic 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)置時間周期單位秒 .withIntervalInHours(2) //兩個小時執(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

          package com.solo.coderiver.user.task;
          import com.solo.coderiver.user.service.LikedService;import lombok.extern.slf4j.Slf4j;import org.apache.commons.lang.time.DateUtils;import org.quartz.JobExecutionContext;import org.quartz.JobExecutionException;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.scheduling.quartz.QuartzJobBean;
          import java.text.SimpleDateFormat;import java.util.Date;
          /** * 點(diǎn)贊的定時任務(wù) */@Slf4jpublic 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)庫里 likedService.transLikedFromRedis2DB(); likedService.transLikedCountFromRedis2DB(); }}

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

          以上就是點(diǎn)贊功能的設(shè)計(jì)與實(shí)現(xiàn),不足之處還請各位大佬多多指教。

          如有更好的實(shí)現(xiàn)方案歡迎在評論區(qū)交流…

          后臺回復(fù)?學(xué)習(xí)資料?領(lǐng)取學(xué)習(xí)視頻


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