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

2022-04-06 13:00:00 浏览数 (1)

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 缓存设计及实现
  • 数据库设计
  • 数据库操作
  • 开启定时任务持久化存储到数据库

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

代码语言：javascript复制
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

代码语言：javascript复制
redis-server

1.2 Redis 与 SpringBoot 项目的整合

  1. 在 pom.xml 中引入依赖
代码语言：javascript复制
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
  1. 在启动类上添加注释 @EnableCaching
代码语言：javascript复制
@SpringBootApplication
@EnableDiscoveryClient
@EnableSwagger2
@EnableFeignClients(basePackages = "com.solo.coderiver.project.client")
@EnableCaching
public 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);
}

}
  1. 编写 Redis 配置类 RedisConfig
代码语言：javascript复制
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
public 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&lt;String, Object&gt; <span class="hljs-title">redisTemplate</span><span class="hljs-params">(
        RedisConnectionFactory redisConnectionFactory)</span>
        <span class="hljs-keyword">throws</span> UnknownHostException </span>{

    Jackson2JsonRedisSerializer&lt;Object&gt; jackson2JsonRedisSerializer = <span class="hljs-keyword">new</span> Jackson2JsonRedisSerializer&lt;Object&gt;(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&lt;String, Object&gt; template = <span class="hljs-keyword">new</span> RedisTemplate&lt;String, Object&gt;();
    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;
}

}

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：

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

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

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

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

RedisService.java

代码语言：javascript复制
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&lt;UserLike&gt; <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&lt;LikedCountDTO&gt; <span class="hljs-title">getLikedCountFromRedis</span><span class="hljs-params">()</span></span>;

}

实现类 RedisServiceImpl.java

代码语言：javascript复制
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
public 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&lt;UserLike&gt; <span class="hljs-title">getLikedDataFromRedis</span><span class="hljs-params">()</span> </span>{
    Cursor&lt;Map.Entry&lt;Object, Object&gt;&gt; cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED, ScanOptions.NONE);
    List&lt;UserLike&gt; list = <span class="hljs-keyword">new</span> ArrayList&lt;&gt;();
    <span class="hljs-keyword">while</span> (cursor.hasNext()){
        Map.Entry&lt;Object, Object&gt; 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&lt;LikedCountDTO&gt; <span class="hljs-title">getLikedCountFromRedis</span><span class="hljs-params">()</span> </span>{
    Cursor&lt;Map.Entry&lt;Object, Object&gt;&gt; cursor = redisTemplate.opsForHash().scan(RedisKeyUtils.MAP_KEY_USER_LIKED_COUNT, ScanOptions.NONE);
    List&lt;LikedCountDTO&gt; list = <span class="hljs-keyword">new</span> ArrayList&lt;&gt;();
    <span class="hljs-keyword">while</span> (cursor.hasNext()){
        Map.Entry&lt;Object, Object&gt; 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;
}

}

用到的工具类和枚举类

RedisKeyUtils, 用于根据一定规则生成 key

代码语言：javascript复制
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();
}

}

LikedStatusEnum 用户点赞状态的枚举类

代码语言：javascript复制
package com.solo.coderiver.user.enums;

import lombok.Getter;
/**

用户点赞的状态

 */
@Getter
public 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;
}

}

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

代码语言：javascript复制
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';

对应的对象 UserLike

代码语言：javascript复制
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
@Data
public 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;
}

}

三、数据库操作

操作数据库同样封装在接口中

LikedService

代码语言：javascript复制
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&lt;UserLike&gt; <span class="hljs-title">saveAll</span><span class="hljs-params">(List&lt;UserLike&gt; 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&lt;UserLike&gt; <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&lt;UserLike&gt; <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>;

}

LikedServiceImpl 实现类

代码语言：javascript复制
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
public 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&lt;UserLike&gt; <span class="hljs-title">saveAll</span><span class="hljs-params">(List&lt;UserLike&gt; 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&lt;UserLike&gt; <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&lt;UserLike&gt; <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&lt;UserLike&gt; 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&lt;LikedCountDTO&gt; 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);
        }
    }
}

}

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
代码语言：javascript复制
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-quartz</artifactId>
</dependency>
  1. 编写配置文件
代码语言：javascript复制
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
public 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();
    }
}
  1. 编写执行任务的类继承自 QuartzJobBean
代码语言：javascript复制
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

 */
@Slf4j
public 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();
}

}

在定时任务中直接调用 LikedService 封装的方法完成数据同步。

以上就是点赞功能的设计与实现，不足之处还请各位大佬多多指教。

如有更好的实现方案欢迎在评论区交流…

项目地址：https://github.com/cachecats/coderiver

云数据库Redis® 数据库 sql 编程算法 linux

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