点赞模块设计 - Redis缓存 + 定时写入数据库实现高性能点赞功能

源码地址：https://github.com/cachecats/coderiver

点赞是作为整个系统的一个小模块，代码在 user-service 用户服务下。

本文基于 SpringCloud, 用户发起点赞、取消点赞后先存入 Redis 中，再每隔两小时从 Redis 读取点赞数据写入数据库中做持久化存储。

点赞功能在很多系统中都有，但别看功能小，想要做好需要考虑的东西还挺多的。

点赞、取消点赞是高频次的操作，若每次都读写数据库，大量的操作会影响数据库性能，所以需要做缓存。

至于多久从 Redis 取一次数据存到数据库中，根据项目的实际情况定吧，我是暂时设了两个小时。

项目需求需要查看都谁点赞了，所以要存储每个点赞的点赞人、被点赞人，不能简单的做计数。

文章分四部分介绍：

Redis 安装请自行查阅相关教程。

说下Docker 安装运行 Redis

<code class="javascript">docker run -d -p 6379:6379 redis:4.0.8</code>

如果已经安装了 Redis，打开命令行，输入启动 Redis 的命令

<code class="javascript">redis-server</code>

<code class="javascript"><dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-data-redis</artifactId></dependency></code>

<code class="javascript">@SpringBootApplication@EnableDiscoveryClient@EnableSwagger2@EnableFeignClients(basePackages = "com.solo.coderiver.project.client")@EnableCachingpublic class UserApplication {<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">main</span><span class="hljs-params">(String[] args)</span> </span>{    SpringApplication.run(UserApplication.class, args);}}</code>

<code class="javascript">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 {<span class="hljs-meta">@Bean</span><span class="hljs-meta">@ConditionalOnMissingBean</span>(name = <span class="hljs-string">"redisTemplate"</span>)<span class="hljs-function"><span class="hljs-keyword">public</span> RedisTemplate<String, Object> <span class="hljs-title">redisTemplate</span><span class="hljs-params">(        RedisConnectionFactory redisConnectionFactory)</span>        <span class="hljs-keyword">throws</span> UnknownHostException </span>{    Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = <span class="hljs-keyword">new</span> Jackson2JsonRedisSerializer<Object>(Object.class);    ObjectMapper om = <span class="hljs-keyword">new</span> ObjectMapper();    om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);    om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);    jackson2JsonRedisSerializer.setObjectMapper(om);    RedisTemplate<String, Object> template = <span class="hljs-keyword">new</span> RedisTemplate<String, Object>();    template.setConnectionFactory(redisConnectionFactory);    template.setKeySerializer(jackson2JsonRedisSerializer);    template.setValueSerializer(jackson2JsonRedisSerializer);    template.setHashKeySerializer(jackson2JsonRedisSerializer);    template.setHashValueSerializer(jackson2JsonRedisSerializer);    template.afterPropertiesSet();    <span class="hljs-keyword">return</span> template;}<span class="hljs-meta">@Bean</span><span class="hljs-meta">@ConditionalOnMissingBean</span>(StringRedisTemplate.class)<span class="hljs-function"><span class="hljs-keyword">public</span> StringRedisTemplate <span class="hljs-title">stringRedisTemplate</span><span class="hljs-params">(        RedisConnectionFactory redisConnectionFactory)</span>        <span class="hljs-keyword">throws</span> UnknownHostException </span>{    StringRedisTemplate template = <span class="hljs-keyword">new</span> StringRedisTemplate();    template.setConnectionFactory(redisConnectionFactory);    <span class="hljs-keyword">return</span> template;}}</code>

至此 Redis 在 SpringBoot 项目中的配置已经完成，可以愉快的使用了。

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：

结构类型

结构存储的值

结构的读写能力

String

可以是字符串、整数或者浮点数

对整个字符串或者字符串的其中一部分执行操作；对象和浮点数执行自增(increment)或者自减(decrement)

List

一个链表，链表上的每个节点都包含了一个字符串

从链表的两端推入或者弹出元素；根据偏移量对链表进行修剪(trim)；读取单个或者多个元素；根据值来查找或者移除元素

Set

包含字符串的无序收集器(unorderedcollection)，并且被包含的每个字符串都是独一无二的、各不相同

添加、获取、移除单个元素；检查一个元素是否存在于某个集合中；计算交集、并集、差集；从集合里卖弄随机获取元素

Hash

Okaaaay

适用于所有人的AI文本和内容生成器

下载

包含键值对的无序散列表

添加、获取、移除单个键值对；获取所有键值对

Zset

字符串成员(member)与浮点数分值(score)之间的有序映射，元素的排列顺序由分值的大小决定

添加、获取、删除单个元素；根据分值范围(range)或者成员来获取元素

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

Redis 各种数据格式的操作方法可以看看 这篇文章 ，写的非常好。

将具体操作方法封装到了 RedisService 接口里

<code class="javascript">import com.solo.coderiver.user.dataobject.UserLike;import com.solo.coderiver.user.dto.LikedCountDTO;import java.util.List;public interface RedisService {<span class="hljs-comment">/** * 点赞。状态为1 * <span class="hljs-doctag">@param</span> likedUserId * <span class="hljs-doctag">@param</span> likedPostId */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">saveLiked2Redis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span></span>;<span class="hljs-comment">/** * 取消点赞。将状态改变为0 * <span class="hljs-doctag">@param</span> likedUserId * <span class="hljs-doctag">@param</span> likedPostId */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">unlikeFromRedis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span></span>;<span class="hljs-comment">/** * 从Redis中删除一条点赞数据 * <span class="hljs-doctag">@param</span> likedUserId * <span class="hljs-doctag">@param</span> likedPostId */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">deleteLikedFromRedis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span></span>;<span class="hljs-comment">/** * 该用户的点赞数加1 * <span class="hljs-doctag">@param</span> likedUserId */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">incrementLikedCount</span><span class="hljs-params">(String likedUserId)</span></span>;<span class="hljs-comment">/** * 该用户的点赞数减1 * <span class="hljs-doctag">@param</span> likedUserId */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">decrementLikedCount</span><span class="hljs-params">(String likedUserId)</span></span>;<span class="hljs-comment">/** * 获取Redis中存储的所有点赞数据 * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">List<UserLike> <span class="hljs-title">getLikedDataFromRedis</span><span class="hljs-params">()</span></span>;<span class="hljs-comment">/** * 获取Redis中存储的所有点赞数量 * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">List<LikedCountDTO> <span class="hljs-title">getLikedCountFromRedis</span><span class="hljs-params">()</span></span>;}</code>

<code class="javascript">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 {<span class="hljs-meta">@Autowired</span>RedisTemplate redisTemplate;<span class="hljs-meta">@Autowired</span>LikedService likedService;<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">saveLiked2Redis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span> </span>{    String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId);    redisTemplate.opsForHash().put(RedisKeyUtils.MAP_KEY_USER_LIKED, key, LikedStatusEnum.LIKE.getCode());}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">unlikeFromRedis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span> </span>{    String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId);    redisTemplate.opsForHash().put(RedisKeyUtils.MAP_KEY_USER_LIKED, key, LikedStatusEnum.UNLIKE.getCode());}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">deleteLikedFromRedis</span><span class="hljs-params">(String likedUserId, String likedPostId)</span> </span>{    String key = RedisKeyUtils.getLikedKey(likedUserId, likedPostId);    redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">incrementLikedCount</span><span class="hljs-params">(String likedUserId)</span> </span>{    redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, <span class="hljs-number">1</span>);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">decrementLikedCount</span><span class="hljs-params">(String likedUserId)</span> </span>{    redisTemplate.opsForHash().increment(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, likedUserId, -<span class="hljs-number">1</span>);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> List<UserLike> <span class="hljs-title">getLikedDataFromRedis</span><span class="hljs-params">()</span> </span>{    Cursor<Map.Entry<Object, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED, ScanOptions.NONE);    List<UserLike> list = <span class="hljs-keyword">new</span> ArrayList<>();    <span class="hljs-keyword">while</span> (cursor.hasNext()){        Map.Entry<Object, Object> entry = cursor.next();        String key = (String) entry.getKey();        <span class="hljs-comment">//分离出 likedUserId，likedPostId</span>        String[] split = key.split(<span class="hljs-string">"::"</span>);        String likedUserId = split[<span class="hljs-number">0</span>];        String likedPostId = split[<span class="hljs-number">1</span>];        Integer value = (Integer) entry.getValue();        <span class="hljs-comment">//组装成 UserLike 对象</span>        UserLike userLike = <span class="hljs-keyword">new</span> UserLike(likedUserId, likedPostId, value);        list.add(userLike);        <span class="hljs-comment">//存到 list 后从 Redis 中删除</span>        redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED, key);    }    <span class="hljs-keyword">return</span> list;}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> List<LikedCountDTO> <span class="hljs-title">getLikedCountFromRedis</span><span class="hljs-params">()</span> </span>{    Cursor<Map.Entry<Object, Object>> cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, ScanOptions.NONE);    List<LikedCountDTO> list = <span class="hljs-keyword">new</span> ArrayList<>();    <span class="hljs-keyword">while</span> (cursor.hasNext()){        Map.Entry<Object, Object> map = cursor.next();        <span class="hljs-comment">//将点赞数量存储在 LikedCountDT</span>        String key = (String)map.getKey();        LikedCountDTO dto = <span class="hljs-keyword">new</span> LikedCountDTO(key, (Integer) map.getValue());        list.add(dto);        <span class="hljs-comment">//从Redis中删除这条记录</span>        redisTemplate.opsForHash().delete(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, key);    }    <span class="hljs-keyword">return</span> list;}}</code>

用到的工具类和枚举类

<code class="javascript">public class RedisKeyUtils {<span class="hljs-comment">//保存用户点赞数据的key</span><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String MAP_KEY_USER_LIKED = <span class="hljs-string">"MAP_USER_LIKED"</span>;<span class="hljs-comment">//保存用户被点赞数量的key</span><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String MAP_KEY_USER_LIKED_COUNT = <span class="hljs-string">"MAP_USER_LIKED_COUNT"</span>;<span class="hljs-comment">/** * 拼接被点赞的用户id和点赞的人的id作为key。格式 222222::333333 * <span class="hljs-doctag">@param</span> likedUserId 被点赞的人id * <span class="hljs-doctag">@param</span> likedPostId 点赞的人的id * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> String <span class="hljs-title">getLikedKey</span><span class="hljs-params">(String likedUserId, String likedPostId)</span></span>{    StringBuilder builder = <span class="hljs-keyword">new</span> StringBuilder();    builder.append(likedUserId);    builder.append(<span class="hljs-string">"::"</span>);    builder.append(likedPostId);    <span class="hljs-keyword">return</span> builder.toString();}}</code>

<code class="javascript">package com.solo.coderiver.user.enums;import lombok.Getter;/**用户点赞的状态 */@Getterpublic enum LikedStatusEnum {    LIKE(1, "点赞"),    UNLIKE(0, "取消点赞/未点赞"),    ;<span class="hljs-keyword">private</span> Integer code;<span class="hljs-keyword">private</span> String msg;LikedStatusEnum(Integer code, String msg) {    <span class="hljs-keyword">this</span>.code = code;    <span class="hljs-keyword">this</span>.msg = msg;}}</code>

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

<code class="javascript">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 null default current_timestamp comment '创建时间',  `update_time` timestamp not null default 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';</code>

对应的对象 UserLike

<code class="javascript">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;/**用户点赞表 */@Entity@Datapublic class UserLike {<span class="hljs-comment">//主键id</span><span class="hljs-meta">@Id</span><span class="hljs-meta">@GeneratedValue</span>(strategy = GenerationType.IDENTITY)<span class="hljs-keyword">private</span> Integer id;<span class="hljs-comment">//被点赞的用户的id</span><span class="hljs-keyword">private</span> String likedUserId;<span class="hljs-comment">//点赞的用户的id</span><span class="hljs-keyword">private</span> String likedPostId;<span class="hljs-comment">//点赞的状态.默认未点赞</span><span class="hljs-keyword">private</span> Integer status = LikedStatusEnum.UNLIKE.getCode();<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">UserLike</span><span class="hljs-params">()</span> </span>{}<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-title">UserLike</span><span class="hljs-params">(String likedUserId, String likedPostId, Integer status)</span> </span>{    <span class="hljs-keyword">this</span>.likedUserId = likedUserId;    <span class="hljs-keyword">this</span>.likedPostId = likedPostId;    <span class="hljs-keyword">this</span>.status = status;}}</code>

操作数据库同样封装在接口中

<code class="javascript">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 {<span class="hljs-comment">/** * 保存点赞记录 * <span class="hljs-doctag">@param</span> userLike * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">UserLike <span class="hljs-title">save</span><span class="hljs-params">(UserLike userLike)</span></span>;<span class="hljs-comment">/** * 批量保存或修改 * <span class="hljs-doctag">@param</span> list */</span><span class="hljs-function">List<UserLike> <span class="hljs-title">saveAll</span><span class="hljs-params">(List<UserLike> list)</span></span>;<span class="hljs-comment">/** * 根据被点赞人的id查询点赞列表（即查询都谁给这个人点赞过） * <span class="hljs-doctag">@param</span> likedUserId 被点赞人的id * <span class="hljs-doctag">@param</span> pageable * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">Page<UserLike> <span class="hljs-title">getLikedListByLikedUserId</span><span class="hljs-params">(String likedUserId, Pageable pageable)</span></span>;<span class="hljs-comment">/** * 根据点赞人的id查询点赞列表（即查询这个人都给谁点赞过） * <span class="hljs-doctag">@param</span> likedPostId * <span class="hljs-doctag">@param</span> pageable * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">Page<UserLike> <span class="hljs-title">getLikedListByLikedPostId</span><span class="hljs-params">(String likedPostId, Pageable pageable)</span></span>;<span class="hljs-comment">/** * 通过被点赞人和点赞人id查询是否存在点赞记录 * <span class="hljs-doctag">@param</span> likedUserId * <span class="hljs-doctag">@param</span> likedPostId * <span class="hljs-doctag">@return</span> */</span><span class="hljs-function">UserLike <span class="hljs-title">getByLikedUserIdAndLikedPostId</span><span class="hljs-params">(String likedUserId, String likedPostId)</span></span>;<span class="hljs-comment">/** * 将Redis里的点赞数据存入数据库中 */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">transLikedFromRedis2DB</span><span class="hljs-params">()</span></span>;<span class="hljs-comment">/** * 将Redis中的点赞数量数据存入数据库 */</span><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">transLikedCountFromRedis2DB</span><span class="hljs-params">()</span></span>;}</code>

<code class="javascript">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 {<span class="hljs-meta">@Autowired</span>UserLikeRepository likeRepository;<span class="hljs-meta">@Autowired</span>RedisService redisService;<span class="hljs-meta">@Autowired</span>UserService userService;<span class="hljs-meta">@Override</span><span class="hljs-meta">@Transactional</span><span class="hljs-function"><span class="hljs-keyword">public</span> UserLike <span class="hljs-title">save</span><span class="hljs-params">(UserLike userLike)</span> </span>{    <span class="hljs-keyword">return</span> likeRepository.save(userLike);}<span class="hljs-meta">@Override</span><span class="hljs-meta">@Transactional</span><span class="hljs-function"><span class="hljs-keyword">public</span> List<UserLike> <span class="hljs-title">saveAll</span><span class="hljs-params">(List<UserLike> list)</span> </span>{    <span class="hljs-keyword">return</span> likeRepository.saveAll(list);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> Page<UserLike> <span class="hljs-title">getLikedListByLikedUserId</span><span class="hljs-params">(String likedUserId, Pageable pageable)</span> </span>{    <span class="hljs-keyword">return</span> likeRepository.findByLikedUserIdAndStatus(likedUserId, LikedStatusEnum.LIKE.getCode(), pageable);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> Page<UserLike> <span class="hljs-title">getLikedListByLikedPostId</span><span class="hljs-params">(String likedPostId, Pageable pageable)</span> </span>{    <span class="hljs-keyword">return</span> likeRepository.findByLikedPostIdAndStatus(likedPostId, LikedStatusEnum.LIKE.getCode(), pageable);}<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">public</span> UserLike <span class="hljs-title">getByLikedUserIdAndLikedPostId</span><span class="hljs-params">(String likedUserId, String likedPostId)</span> </span>{    <span class="hljs-keyword">return</span> likeRepository.findByLikedUserIdAndLikedPostId(likedUserId, likedPostId);}<span class="hljs-meta">@Override</span><span class="hljs-meta">@Transactional</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">transLikedFromRedis2DB</span><span class="hljs-params">()</span> </span>{    List<UserLike> list = redisService.getLikedDataFromRedis();    <span class="hljs-keyword">for</span> (UserLike like : list) {        UserLike ul = getByLikedUserIdAndLikedPostId(like.getLikedUserId(), like.getLikedPostId());        <span class="hljs-keyword">if</span> (ul == <span class="hljs-keyword">null</span>){            <span class="hljs-comment">//没有记录，直接存入</span>            save(like);        }<span class="hljs-keyword">else</span>{            <span class="hljs-comment">//有记录，需要更新</span>            ul.setStatus(like.getStatus());            save(ul);        }    }}<span class="hljs-meta">@Override</span><span class="hljs-meta">@Transactional</span><span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">transLikedCountFromRedis2DB</span><span class="hljs-params">()</span> </span>{    List<LikedCountDTO> list = redisService.getLikedCountFromRedis();    <span class="hljs-keyword">for</span> (LikedCountDTO dto : list) {        UserInfo user = userService.findById(dto.getId());        <span class="hljs-comment">//点赞数量属于无关紧要的操作，出错无需抛异常</span>        <span class="hljs-keyword">if</span> (user != <span class="hljs-keyword">null</span>){            Integer likeNum = user.getLikeNum() + dto.getCount();            user.setLikeNum(likeNum);            <span class="hljs-comment">//更新点赞数量</span>            userService.updateInfo(user);        }    }}}</code>

数据库的操作就这些，主要还是增删改查。

定时任务 Quartz 很强大，就用它了。

Quartz 使用步骤：

<code class="javascript"><dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-quartz</artifactId></dependency></code>

<code class="javascript">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 {<span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> String LIKE_TASK_IDENTITY = <span class="hljs-string">"LikeTaskQuartz"</span>;<span class="hljs-meta">@Bean</span><span class="hljs-function"><span class="hljs-keyword">public</span> JobDetail <span class="hljs-title">quartzDetail</span><span class="hljs-params">()</span></span>{    <span class="hljs-keyword">return</span> JobBuilder.newJob(LikeTask.class).withIdentity(LIKE_TASK_IDENTITY).storeDurably().build();}<span class="hljs-meta">@Bean</span><span class="hljs-function"><span class="hljs-keyword">public</span> Trigger <span class="hljs-title">quartzTrigger</span><span class="hljs-params">()</span></span>{    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();    }}</code>

<code class="javascript">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;/**点赞的定时任务 */@Slf4jpublic class LikeTask extends QuartzJobBean {<span class="hljs-meta">@Autowired</span>LikedService likedService;<span class="hljs-keyword">private</span> SimpleDateFormat sdf = <span class="hljs-keyword">new</span> SimpleDateFormat(<span class="hljs-string">"yyyy-MM-dd HH:mm:ss"</span>);<span class="hljs-meta">@Override</span><span class="hljs-function"><span class="hljs-keyword">protected</span> <span class="hljs-keyword">void</span> <span class="hljs-title">executeInternal</span><span class="hljs-params">(JobExecutionContext jobExecutionContext)</span> <span class="hljs-keyword">throws</span> JobExecutionException </span>{    log.info(<span class="hljs-string">"LikeTask-------- {}"</span>, sdf.format(<span class="hljs-keyword">new</span> Date()));    <span class="hljs-comment">//将 Redis 里的点赞信息同步到数据库里</span>    likedService.transLikedFromRedis2DB();    likedService.transLikedCountFromRedis2DB();}}</code>

在定时任务中直接调用 LikedService 封装的方法完成数据同步。