Spring Cloud中怎么使用Redis实现点赞和取消点赞功能，相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
一、Redis 缓存设计及实现
1.1 Redis 安装及运行
Redis 安装请自行查阅相关教程。
说下Docker 安装运行 Redis
docker run -d -p 6379:6379 redis:4.0.8如果已经安装了 Redis，打开命令行，输入启动 Redis 的命令
redis-server1.2 Redis 与 SpringBoot 项目的整合
1.在 pom.xml 中引入依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency>2.在启动类上添加注释 @EnableCaching
@SpringBootApplication @EnableDiscoveryClient @EnableSwagger2 @EnableFeignClients(basePackages = "com.solo.coderiver.project.client") @EnableCaching publicclass UserApplication { public static void main(String[] args) { SpringApplication.run(UserApplication.class, args); } }3.编写 Redis 配置类 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; @Configuration publicclass 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; } }至此 Redis 在 SpringBoot 项目中的配置已经完成，可以愉快的使用了。
1.3 Redis 的数据结构类型
Redis 可以存储键与5种不同数据结构类型之间的映射，这5种数据结构类型分别为String（字符串）、List（列表）、Set（集合）、Hash（散列）和 Zset（有序集合）。
下面来对这5种数据结构类型作简单的介绍：
1.4 点赞数据在 Redis 中的存储格式
用 Redis 存储两种数据，一种是记录点赞人、被点赞人、点赞状态的数据，另一种是每个用户被点赞了多少次，做个简单的计数。
由于需要记录点赞人和被点赞人，还有点赞状态（点赞、取消点赞），还要固定时间间隔取出 Redis 中所有点赞数据，分析了下 Redis 数据格式中 Hash 最合适。
因为 Hash 里的数据都是存在一个键里，可以通过这个键很方便的把所有的点赞数据都取出。这个键里面的数据还可以存成键值对的形式，方便存入点赞人、被点赞人和点赞状态。
设点赞人的 id 为 likedPostId，被点赞人的 id 为 likedUserId ，点赞时状态为 1，取消点赞状态为 0。将点赞人 id 和被点赞人 id 作为键，两个 id 中间用 :: 隔开，点赞状态作为值。
所以如果用户点赞，存储的键为：likedUserId::likedPostId，对应的值为 1 。取消点赞，存储的键为：likedUserId::likedPostId，对应的值为 0 。取数据时把键用 :: 切开就得到了两个id，也很方便。
在可视化工具 RDM 中看到的是这样子
1.5 操作 Redis
将具体操作方法封装到了 RedisService 接口里
RedisService.java
import com.solo.coderiver.user.dataobject.UserLike; import com.solo.coderiver.user.dto.LikedCountDTO; import java.util.List; publicinterface RedisService { void saveLiked2Redis(String likedUserId, String likedPostId); void unlikeFromRedis(String likedUserId, String likedPostId); void deleteLikedFromRedis(String likedUserId, String likedPostId); void incrementLikedCount(String likedUserId); void decrementLikedCount(String likedUserId); List<UserLike> getLikedDataFromRedis(); List<LikedCountDTO> getLikedCountFromRedis(); }实现类 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 @Slf4j publicclass 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<UserLike> getLikedDataFromRedis() { Cursor<Map.Entry<Object, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED, ScanOptions.NONE); List<UserLike> list = new ArrayList<>(); while (cursor.hasNext()){ Map.Entry<Object, Object> entry = cursor.next(); String key = (String) entry.getKey(); //分离出 likedUserId，likedPostId String[] split = key.split("::"); String likedUserId = split[0]; String likedPostId = split[1]; Integer value = (Integer) entry.getValue(); //组装成 UserLike 对象 UserLike userLike = new UserLike(likedUserId, likedPostId, value); list.add(userLike); //存到 list 后从 Redis 中删除 redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key); } return list; } @Override public List<LikedCountDTO> getLikedCountFromRedis() { Cursor<Map.Entry<Object, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, ScanOptions.NONE); List<LikedCountDTO> list = new ArrayList<>(); while (cursor.hasNext()){ Map.Entry<Object, Object> map = cursor.next(); //将点赞数量存储在 LikedCountDT String key = (String)map.getKey(); LikedCountDTO dto = new LikedCountDTO(key, (Integer) map.getValue()); list.add(dto); //从Redis中删除这条记录 redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, key); } return list; } }用到的工具类和枚举类
RedisKeyUtils, 用于根据一定规则生成 key
publicclass RedisKeyUtils { //保存用户点赞数据的key publicstaticfinal String MAP_KEY_USER_LIKED = "MAP_USER_LIKED"; //保存用户被点赞数量的key publicstaticfinal String MAP_KEY_USER_LIKED_COUNT = "MAP_USER_LIKED_COUNT"; public static String getLikedKey(String likedUserId, String likedPostId){ StringBuilder builder = new StringBuilder(); builder.append(likedUserId); builder.append("::"); builder.append(likedPostId); return builder.toString(); } }LikedStatusEnum 用户点赞状态的枚举类
package com.solo.coderiver.user.enums; import lombok.Getter; @Getter publicenum LikedStatusEnum { LIKE(1, "点赞"), UNLIKE(0, "取消点赞/未点赞"), ; private Integer code; private String msg; LikedStatusEnum(Integer code, String msg) { this.code = code; this.msg = msg; } }二、数据库设计
数据库表中至少要包含三个字段：被点赞用户id，点赞用户id，点赞状态。再加上主键id，创建时间，修改时间就行了。
建表语句
create table `user_like`( `id` int not null auto_increment, `liked_user_id` varchar(32) not null comment '被点赞的用户id', `liked_post_id` varchar(32) not null comment '点赞的用户id', `status` tinyint(1) default'1' comment '点赞状态，0取消，1点赞', `create_time` timestamp not nulldefault current_timestamp comment '创建时间', `update_time` timestamp not nulldefault current_timestamp on update current_timestamp comment '修改时间', primary key(`id`), INDEX `liked_user_id`(`liked_user_id`), INDEX `liked_post_id`(`liked_post_id`) ) comment '用户点赞表';对应的对象 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; @Entity @Data publicclass UserLike { //主键id @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; //被点赞的用户的id private String likedUserId; //点赞的用户的id private String likedPostId; //点赞的状态.默认未点赞 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、数据库操作
操作数据库同样封装在接口中
LikedService
import com.solo.coderiver.user.dataobject.UserLike; import org.springframework.data.domain.Page; import org.springframework.data.domain.Pageable; import java.util.List; publicinterface LikedService { UserLike save(UserLike userLike); List<UserLike> saveAll(List<UserLike> list); Page<UserLike> getLikedListByLikedUserId(String likedUserId, Pageable pageable); Page<UserLike> getLikedListByLikedPostId(String likedPostId, Pageable pageable); UserLike getByLikedUserIdAndLikedPostId(String likedUserId, String likedPostId); void transLikedFromRedis2DB(); void transLikedCountFromRedis2DB(); }LikedServiceImpl 实现类
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 @Slf4j publicclass 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> 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<UserLike> list = redisService.getLikedDataFromRedis(); for (UserLike like : list) { UserLike ul = getByLikedUserIdAndLikedPostId(like.getLikedUserId(), like.getLikedPostId()); if (ul == null){ //没有记录，直接存入 save(like); }else{ //有记录，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()); //点赞数量属于无关紧要的操作，出错无需抛异常 if (user != null){ Integer likeNum = user.getLikeNum() + dto.getCount(); user.setLikeNum(likeNum); //更新点赞数量 userService.updateInfo(user); } } } }数据库的操作就这些，主要还是增删改查。
四、开启定时任务持久化存储到数据库
定时任务 Quartz 很强大，就用它了。
Quartz 使用步骤：
1.添加依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-quartz</artifactId> </dependency>2.编写配置文件
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; @Configuration publicclass QuartzConfig { privatestaticfinal 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) //设置时间周期单位秒 .withIntervalInHours(2) //两个小时执行一次 .repeatForever(); return TriggerBuilder.newTrigger().forJob(quartzDetail()) .withIdentity(LIKE_TASK_IDENTITY) .withSchedule(scheduleBuilder) .build(); } }3.编写执行任务的类继承自 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; @Slf4j publicclass 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())); //将 Redis 里的点赞信息同步到数据库里 likedService.transLikedFromRedis2DB(); likedService.transLikedCountFromRedis2DB(); } }在定时任务中直接调用 LikedService 封装的方法完成数据同步。
看完上述内容，你们掌握Spring Cloud中怎么使用Redis实现点赞和取消点赞功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注亿速云行业资讯频道，感谢各位的阅读！
