Redis是如何實(shí)現(xiàn)點(diǎn)贊、取消點(diǎn)贊的?
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
2(basePackages = "com.solo.coderiver.project.client")public 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;public class RedisConfig {public RedisTemplateredisTemplate( RedisConnectionFactory redisConnectionFactory)throws UnknownHostException {Jackson2JsonRedisSerializerObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);jackson2JsonRedisSerializer.setObjectMapper(om);RedisTemplatetemplate = new RedisTemplate (); template.setConnectionFactory(redisConnectionFactory);template.setKeySerializer(jackson2JsonRedisSerializer);template.setValueSerializer(jackson2JsonRedisSerializer);template.setHashKeySerializer(jackson2JsonRedisSerializer);template.setHashValueSerializer(jackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}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*/ListgetLikedDataFromRedis() ;/*** 獲取Redis中存儲的所有點(diǎn)贊數(shù)量* @return*/ListgetLikedCountFromRedis() ;}
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;public class RedisServiceImpl implements RedisService {RedisTemplate redisTemplate;LikedService likedService;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());}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());}public void deleteLikedFromRedis(String likedUserId, String likedPostId) {String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId);redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key);}public void incrementLikedCount(String likedUserId) {redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, 1);}public void decrementLikedCount(String likedUserId) {redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, -1);}public ListgetLikedDataFromRedis() { CursorObject , Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED, ScanOptions.NONE);Listlist = new ArrayList<>(); while (cursor.hasNext()){Map.Entry<Object, Object> entry = cursor.next();String key = (String) entry.getKey();//分離出 likedUserId,likedPostIdString[] 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;}public ListgetLikedCountFromRedis() { CursorObject , Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, ScanOptions.NONE);Listlist = new ArrayList<>(); while (cursor.hasNext()){Map.Entry<Object, Object> map = cursor.next();//將點(diǎn)贊數(shù)量存儲在 LikedCountDTString 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keypublic static final String MAP_KEY_USER_LIKED = "MAP_USER_LIKED";//保存用戶被點(diǎn)贊數(shù)量的keypublic 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)*/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;}}
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*/public class UserLike {//主鍵id(strategy = GenerationType.IDENTITY)private Integer id;//被點(diǎn)贊的用戶的idprivate String likedUserId;//點(diǎn)贊的用戶的idprivate 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*/ListsaveAll(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*/PagegetLikedListByLikedUserId(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*/PagegetLikedListByLikedPostId(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;4jpublic class LikedServiceImpl implements LikedService {UserLikeRepository likeRepository;RedisService redisService;UserService userService;public UserLike save(UserLike userLike) {return likeRepository.save(userLike);}public ListsaveAll(List {list) return likeRepository.saveAll(list);}public PagegetLikedListByLikedUserId(String likedUserId, Pageable pageable) {return likeRepository.findByLikedUserIdAndStatus(likedUserId, LikedStatusEnum.LIKE.getCode(), pageable);}public PagegetLikedListByLikedPostId(String likedPostId, Pageable pageable) {return likeRepository.findByLikedPostIdAndStatus(likedPostId, LikedStatusEnum.LIKE.getCode(), pageable);}public UserLike getByLikedUserIdAndLikedPostId(String likedUserId, String likedPostId) {return likeRepository.findByLikedUserIdAndLikedPostId(likedUserId, likedPostId);}public void transLikedFromRedis2DB() {Listlist = 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);}}}public void transLikedCountFromRedis2DB() {Listlist = 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;public class QuartzConfig {private static final String LIKE_TASK_IDENTITY = "LikeTaskQuartz";public JobDetail quartzDetail(){return JobBuilder.newJob(LikeTask.class).withIdentity(LIKE_TASK_IDENTITY).storeDurably().build();}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)*/4jpublic class LikeTask extends QuartzJobBean {LikedService likedService;private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");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…
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