Sorted Sets数据类型就像是set和hash的混合，与sets一样，Sorted Sets是唯一的，不重复的字符串组成。可以说Sorted Sets也是Sets的一种。
Sorted Sets是通过Skip List(跳跃表)和hash Table(哈希表)的双端口数据结构实现的，因此每次添加元素时，Redis都会执行O(log(N))操作。所以当我们要求排序的时候，Redis根本不需要做任何工作了，早已经全部排好序了。元素的分数可以随时更新。
依赖
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>3.7.1</version>
</dependency>
写一个Redis的接口类
public interface RedisClient {
//新增
Long zAdd(String key,String value,Double score);
//获取排行
Set<String> zrevrange(String key, int start, int stop);
//增分
Double zincrby(String key, double increment, String value);
// 获取分数
Double score(String key,String value);
// 计数器
Double incrByFloat(String key, double increment);
}
接着写一个Redis 实现类
public class RedisAloneClient implements RedisClient {
@Autowired(required = false)
private JedisPool jedisPool;
@Override
public Long zAdd(String key, String value, Double score) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.zadd(key,score,value);
} finally {
closeJedis(jedis);
}
}
@Override
public Set<String> zrevrange(String key, int start, int stop) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.zrevrange(key,start,stop);
} finally {
closeJedis(jedis);
}
}
@Override
public Double zincrby(String key, double increment, String value) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.zincrby(key,increment,value);
} finally {
closeJedis(jedis);
}
}
@Override
public Double incrByFloat(String key, double increment){
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.incrByFloat(key,increment);
} finally {
closeJedis(jedis);
}
}
@Override
public Double score(String key, String value) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
return jedis.zscore(key,value);
} finally {
closeJedis(jedis);
}
}
private void closeJedis(Jedis jedis) {
if (null != jedis) {
jedis.close();
}
}
}
在写Controller类之前先写入参和出参的类
1、新增和更新入参类
@Data
public class RankingParam {
//用户Id
private String userId;
//分数
private Double score;
}
2、获取排行榜的入参类
@Data
public class RankingTopParam {
//开始排名
private Integer start;
//结束排名
private Integer end;
}
3、返回排行榜出参类
@Data
public class RankingTopResult {
//用户Id
private String userId;
//分数
private Double score;
}
接着写Controller类
@RestController
@RequestMapping("/rankingList")
public class RankingListController {
@Resource
RankingListServiceFacade rankingListServiceFacade;
@PostMapping("/add")
public Result addRankingList(@RequestBody RankingParam param){
return rankingListServiceFacade.addRankingList(param);
}
@PostMapping("/updateScore")
public Result updateScore(@RequestBody RankingParam param){
return rankingListServiceFacade.updateStore(param);
}
@PostMapping("/getRankingListTop")
public Result<List<RankingTopResult>> getRankingListTop(@RequestBody RankingTopParam param){
return rankingListServiceFacade.getRankingListTop(param);
}
}
接着写Facade类
public interface RankingListServiceFacade {
/**
* 新增排行榜
* @param param
* @return
*/
Result addRankingList(RankingParam param);
/**
* 新增分数
* @param param
* @return
*/
Result updateStore(RankingParam param);
/**
* 获取排行榜
* @param param
* @return
*/
Result<List<RankingTopResult>> getRankingListTop(RankingTopParam param);
}
impl类
@Service(value = "rankingListFacade")
public class RankingListServiceFacadeImpl implements RankingListServiceFacade {
@Resource
private RedisClient redisClient;
static final String RANKING_LIST_KEY = "SCORE_RANK";
@Override
public Result addRankingList(RankingParam param){
redisClient.zAdd(RANKING_LIST_KEY,param.getUserId(),param.getScore());
return Result.success("新增成功");
}
@Override
public Result updateStore(RankingParam param){
redisClient.zincrby(RANKING_LIST_KEY,param.getScore(),param.getUserId());
return Result.success("加分成功");
}
@Override
public Result<List<RankingTopResult>> getRankingListTop(RankingTopParam param){
Set<String> stringSet = redisClient.zrevrange(RANKING_LIST_KEY,param.getStart(),param.getEnd());
List<RankingTopResult> rankingTopResults = new ArrayList<>();
for(String userId:stringSet){
Double score = redisClient.score(RANKING_LIST_KEY,userId);
RankingTopResult rankingTopResult = new RankingTopResult();
rankingTopResult.setUserId(userId);
rankingTopResult.setScore(score);
rankingTopResults.add(rankingTopResult);
}
return Result.success(rankingTopResults);
}
}
测试，新增和更新分数都调用add
截屏2022-05-23 13.58.24.png
获取排行旁
截屏2022-05-23 13.59.21.png
只需要做新增更新的操作后，直接就可以获取排行榜了，当然这只是个简单的demo，如果要实现复杂的排行榜自己修改。
思考：
1、比如要返回用户名和头像怎么办
2、如果获取前10名+用户自己的排名怎么实现
3、排名数据如何同步到数据库
扩展
如果实现计数器该怎么实现？
@Service(value = "redisCounterServiceFacade")
public class RedisCounterServiceFacadeImpl implements RedisCounterServiceFacade {
@Resource
private RedisClient redisClient;
@Override
public Result addCounter(CounterParam param) {
redisClient.incrByFloat(param.getUserId(),param.getScore());
return Result.success("");
}
@Override
public Result updateCounter(CounterParam param){
redisClient.incrByFloat(param.getUserId(),param.getScore());
return Result.success("");
}
@Override
public Result<CounterResult> getCounter(CounterParam param){
String score = redisClient.get(param.getUserId());
CounterResult counterResult = new CounterResult();
counterResult.setUserId(param.getUserId());
counterResult.setScore(Double.parseDouble(score));
return Result.success(counterResult);
}
}
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