SpringBoot + Redis：模擬 10w 人的秒殺搶單
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Jedis的nx生成鎖
如何刪除鎖 模擬搶單動作(10w個人開搶) jedis的nx生成鎖
????redis.clients
????jedis
public?boolean?setnx(String?key,?String?val)?{
????????Jedis?jedis?=?null;
????????try?{
????????????jedis?=?jedisPool.getResource();
????????????if?(jedis?==?null)?{
????????????????return?false;
????????????}
????????????return?jedis.set(key,?val,?"NX",?"PX",?1000?*?60).
????????????????????equalsIgnoreCase("ok");
????????}?catch?(Exception?ex)?{
????????}?finally?{
????????????if?(jedis?!=?null)?{
????????????????jedis.close();
????????????}
????????}
????????return?false;
????}
NX：是否存在key，存在就不set成功 PX：key過期時間單位設(shè)置為毫秒（EX：單位秒）
@GetMapping("/setnx/{key}/{val}")
public?boolean?setnx(@PathVariable?String?key,?@PathVariable?String?val)?{
?????return?jedisCom.setnx(key,?val);
}
如何刪除鎖
public?int?delnx(String?key,?String?val)?{
????????Jedis?jedis?=?null;
????????try?{
????????????jedis?=?jedisPool.getResource();
????????????if?(jedis?==?null)?{
????????????????return?0;
????????????}
????????????//if?redis.call('get','orderkey')=='1111'?then?return?redis.call('del','orderkey')?else?return?0?end
????????????StringBuilder?sbScript?=?new?StringBuilder();
????????????sbScript.append("if?redis.call('get','").append(key).append("')").append("=='").append(val).append("'").
????????????????????append("?then?").
????????????????????append("????return?redis.call('del','").append(key).append("')").
????????????????????append("?else?").
????????????????????append("????return?0").
????????????????????append("?end");
????????????return?Integer.valueOf(jedis.eval(sbScript.toString()).toString());
????????}?catch?(Exception?ex)?{
????????}?finally?{
????????????if?(jedis?!=?null)?{
????????????????jedis.close();
????????????}
????????}
????????return?0;
????}
@GetMapping("/delnx/{key}/{val}")
public?int?delnx(@PathVariable?String?key,?@PathVariable?String?val)?{
???return?jedisCom.delnx(key,?val);
}
模擬搶單動作（10w個人開搶）
//總庫存
????private?long?nKuCuen?=?0;
????//商品key名字
????private?String?shangpingKey?=?"computer_key";
????//獲取鎖的超時時間?秒
????private?int?timeout?=?30?*?1000;
????@GetMapping("/qiangdan")
????public?List?qiangdan()?{
????????//搶到商品的用戶
????????List?shopUsers?=?new?ArrayList<>();
????????//構(gòu)造很多用戶
????????List?users?=?new?ArrayList<>();
????????IntStream.range(0,?100000).parallel().forEach(b?->?{
????????????users.add("神牛-"?+?b);
????????});
????????//初始化庫存
????????nKuCuen?=?10;
????????//模擬開搶
????????users.parallelStream().forEach(b?->?{
????????????String?shopUser?=?qiang(b);
????????????if?(!StringUtils.isEmpty(shopUser))?{
????????????????shopUsers.add(shopUser);
????????????}
????????});
????????return?shopUsers;
????}
/**
?????*?模擬搶單動作
?????*
?????*?@param?b
?????*?@return
?????*/
????private?String?qiang(String?b)?{
????????//用戶開搶時間
????????long?startTime?=?System.currentTimeMillis();
????????//未搶到的情況下，30秒內(nèi)繼續(xù)獲取鎖
????????while?((startTime?+?timeout)?>=?System.currentTimeMillis())?{
????????????//商品是否剩余
????????????if?(nKuCuen?<=?0)?{
????????????????break;
????????????}
????????????if?(jedisCom.setnx(shangpingKey,?b))?{
????????????????//用戶b拿到鎖
????????????????logger.info("用戶{}拿到鎖...",?b);
????????????????try?{
????????????????????//商品是否剩余
????????????????????if?(nKuCuen?<=?0)?{
????????????????????????break;
????????????????????}
????????????????????//模擬生成訂單耗時操作，方便查看：神牛-50?多次獲取鎖記錄
????????????????????try?{
????????????????????????TimeUnit.SECONDS.sleep(1);
????????????????????}?catch?(InterruptedException?e)?{
????????????????????????e.printStackTrace();
????????????????????}
????????????????????//搶購成功，商品遞減，記錄用戶
????????????????????nKuCuen?-=?1;
????????????????????//搶單成功跳出
????????????????????logger.info("用戶{}搶單成功跳出...所剩庫存：{}",?b,?nKuCuen);
????????????????????return?b?+?"搶單成功，所剩庫存："?+?nKuCuen;
????????????????}?finally?{
????????????????????logger.info("用戶{}釋放鎖...",?b);
????????????????????//釋放鎖
????????????????????jedisCom.delnx(shangpingKey,?b);
????????????????}
????????????}?else?{
????????????????//用戶b沒拿到鎖，在超時范圍內(nèi)繼續(xù)請求鎖，不需要處理
//????????????????if?(b.equals("神牛-50")?||?b.equals("神牛-69"))?{
//????????????????????logger.info("用戶{}等待獲取鎖...",?b);
//????????????????}
????????????}
????????}
????????return?"";
????}
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