redis秒杀案例

redis秒杀案例:

1.连接池:

public class JedisPoolUtil {
	private static volatile JedisPool jedisPool = null;

	private JedisPoolUtil() {
	}

	public static JedisPool getJedisPoolInstance() {
		if (null == jedisPool) {
			synchronized (JedisPoolUtil.class) {
				if (null == jedisPool) {
					JedisPoolConfig poolConfig = new JedisPoolConfig();
					poolConfig.setMaxTotal(200);
					poolConfig.setMaxIdle(32);
					poolConfig.setMaxWaitMillis(100*1000);
					poolConfig.setBlockWhenExhausted(true);
					poolConfig.setTestOnBorrow(true);  // ping  PONG
				 
					jedisPool = new JedisPool(poolConfig, "192.168.44.168", 6379, 60000 );
				}
			}
		}
		return jedisPool;
	}

	public static void release(JedisPool jedisPool, Jedis jedis) {
		if (null != jedis) {
			jedisPool.returnResource(jedis);
		}
	}

}

2.秒杀过程:

public class SecKill_redis {

	public static void main(String[] args) {
		Jedis jedis =new Jedis("192.168.44.168",6379);
		System.out.println(jedis.ping());
		jedis.close();
	}

	//秒杀过程
	public static boolean doSecKill(String uid,String prodid) throws IOException {
		//1 uid和prodid非空判断
		if(uid == null || prodid == null) {
			return false;
		}

		//2 连接redis
		//Jedis jedis = new Jedis("192.168.44.168",6379);
		//通过连接池得到jedis对象
		JedisPool jedisPoolInstance = JedisPoolUtil.getJedisPoolInstance();
		Jedis jedis = jedisPoolInstance.getResource();

		//3 拼接key
		// 3.1 库存key
		String kcKey = "sk:"+prodid+":qt";
		// 3.2 秒杀成功用户key
		String userKey = "sk:"+prodid+":user";

		//监视库存
		jedis.watch(kcKey);

		//4 获取库存,如果库存null,秒杀还没有开始
		String kc = jedis.get(kcKey);
		if(kc == null) {
			System.out.println("秒杀还没有开始,请等待");
			jedis.close();
			return false;
		}

		// 5 判断用户是否重复秒杀操作
		if(jedis.sismember(userKey, uid)) {
			System.out.println("已经秒杀成功了,不能重复秒杀");
			jedis.close();
			return false;
		}

		//6 判断如果商品数量,库存数量小于1,秒杀结束
		if(Integer.parseInt(kc)<=0) {
			System.out.println("秒杀已经结束了");
			jedis.close();
			return false;
		}

		//7 秒杀过程
		//使用事务
		Transaction multi = jedis.multi();

		//组队操作
		multi.decr(kcKey);
		multi.sadd(userKey,uid);

		//执行
		List results = multi.exec();

		if(results == null || results.size()==0) {
			System.out.println("秒杀失败了....");
			jedis.close();
			return false;
		}

		//7.1 库存-1
		//jedis.decr(kcKey);
		//7.2 把秒杀成功用户添加清单里面
		//jedis.sadd(userKey,uid);

		System.out.println("秒杀成功了..");
		jedis.close();
		return true;
	}
} 
  

 3.脚本

public class SecKill_redisByScript {
	
	private static final  org.slf4j.Logger logger =LoggerFactory.getLogger(SecKill_redisByScript.class) ;

	public static void main(String[] args) {
		JedisPool jedispool =  JedisPoolUtil.getJedisPoolInstance();
 
		Jedis jedis=jedispool.getResource();
		System.out.println(jedis.ping());
		
		Set set=new HashSet();

	//	doSecKill("201","sk:0101");
	}
	
	static String secKillScript ="local userid=KEYS[1];\r\n" + 
			"local prodid=KEYS[2];\r\n" + 
			"local qtkey='sk:'..prodid..\":qt\";\r\n" + 
			"local usersKey='sk:'..prodid..\":usr\";\r\n" + 
			"local userExists=redis.call(\"sismember\",usersKey,userid);\r\n" + 
			"if tonumber(userExists)==1 then \r\n" + 
			"   return 2;\r\n" + 
			"end\r\n" + 
			"local num= redis.call(\"get\" ,qtkey);\r\n" + 
			"if tonumber(num)<=0 then \r\n" + 
			"   return 0;\r\n" + 
			"else \r\n" + 
			"   redis.call(\"decr\",qtkey);\r\n" + 
			"   redis.call(\"sadd\",usersKey,userid);\r\n" + 
			"end\r\n" + 
			"return 1" ;
			 
	static String secKillScript2 = 
			"local userExists=redis.call(\"sismember\",\"{sk}:0101:usr\",userid);\r\n" +
			" return 1";

	public static boolean doSecKill(String uid,String prodid) throws IOException {

		JedisPool jedispool =  JedisPoolUtil.getJedisPoolInstance();
		Jedis jedis=jedispool.getResource();

		 //String sha1=  .secKillScript;
		String sha1=  jedis.scriptLoad(secKillScript);
		Object result= jedis.evalsha(sha1, 2, uid,prodid);

		  String reString=String.valueOf(result);
		if ("0".equals( reString )  ) {
			System.err.println("已抢空!!");
		}else if("1".equals( reString )  )  {
			System.out.println("抢购成功!!!!");
		}else if("2".equals( reString )  )  {
			System.err.println("该用户已抢过!!");
		}else{
			System.err.println("抢购异常!!");
		}
		jedis.close();
		return true;
	}
}

 

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