新入职的妹子问我Redis是如何实现点赞、取消点赞的？这不秀一波

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

redis-server

<dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-data-redis</artifactId></dependency>

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

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<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;    }}

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

public class RedisKeyUtils {    //保存用户点赞数据的key    public static final String MAP_KEY_USER_LIKED = "MAP_USER_LIKED";    //保存用户被点赞数量的key    public static final String MAP_KEY_USER_LIKED_COUNT = "MAP_USER_LIKED_COUNT";    /**     * 拼接被点赞的用户id和点赞的人的id作为key。格式 222222::333333     * @param likedUserId 被点赞的人id     * @param likedPostId 点赞的人的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();    }}

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"),    ;    private Integer code;    private String msg;    LikedStatusEnum(Integer code, String msg) {        this.code = code;        this.msg = msg;    }}

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';

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 {    //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; }}

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 {    /** * 保存点赞记录 * @param userLike * @return */    UserLike save(UserLike userLike);    /** * 批量保存或修改 * @param list */    List<UserLike> saveAll(List<UserLike> list);    /** * 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） * @param likedUserId 被点赞人的id * @param pageable * @return */    Page<UserLike> getLikedListByLikedUserId(String likedUserId, Pageable pageable);    /** * 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） * @param likedPostId * @param pageable * @return */    Page<UserLike> getLikedListByLikedPostId(String likedPostId, Pageable pageable);    /** * 通过被点赞人和点赞人id查询是否存在点赞记录 * @param likedUserId * @param likedPostId * @return */    UserLike getByLikedUserIdAndLikedPostId(String likedUserId, String likedPostId);    /** * 将Redis里的点赞数据存入数据库中 */    void transLikedFromRedis2DB();    /** * 将Redis中的点赞数量数据存入数据库 */    void transLikedCountFromRedis2DB();}

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<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); } } }}

<dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-quartz</artifactId></dependency>

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)  //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(); }}

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 {    @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(); }}