[大数据]redis(五) - redis 实现商品秒杀

1、依赖

 <dependency>
	<groupId>redis.clients</groupId>
	<artifactId>jedis</artifactId>
	<version>3.7.0</version>
</dependency>

2、redis 连接池

public class RedisPoolUtil {

    private static volatile JedisPool jedisPool =null;

    private RedisPoolUtil(){}

    public static JedisPool getJedisPoolInstatnce(){
        if (jedisPool ==null){
            synchronized (RedisPoolUtil.class){
                if (jedisPool == null){
                    JedisPoolConfig config=new JedisPoolConfig();
                    config.setMaxTotal(200);
                    config.setMaxIdle(32);
                    config.setMaxWaitMillis(100*1000);
                    config.setBlockWhenExhausted(true);
                    config.setTestOnBorrow(true);
                    jedisPool =new JedisPool(config,"127.0.0.1",6379,6000);
                }
            }
        }
        return jedisPool;
    }
}

3、Service

public class SecKillService {
	//lua 脚本
    private static String SecKillScript="local userid=KEYS[1];\n" +
            "local prodid=KEYS[2];\n" +
            "local uidKey=\"prod:user:\"..userid;\n" +
            "local proKey=\"prod:kc:\"..prodid;\n" +
            "--redis.log(redis.LOG_NOTICE,uidKey);\n" +
            "--判断是否有库存，没有表示未开启秒杀\n" +
            "local userExists=redis.call(\"exists\",proKey);\n" +
            "if tonumber(userExists)==0 then\n" +
            "    return \"0\";\n" +
            "end\n" +
            "--判断库存是否足够，不够停止秒杀\n" +
            "local num=redis.call(\"get\",proKey);\n" +
            "redis.log(redis.LOG_NOTICE,proKey);\n" +
            "if tonumber(num) <=0 then\n" +
            "    return \"1\";\n" +
            "end\n" +
            "--判断用户是否已参与过秒杀活动\n" +
            "local isMember=redis.call(\"sisMember\",uidKey,userid);\n" +
            "if tonumber(isMember)==1 then\n" +
            "    return \"2\";\n" +
            "else\n" +
            "    redis.call(\"decr\",proKey);\n" +
            "    redis.call(\"sadd\",uidKey,userid);\n" +
            "end\n" +
            "return \"3\";";


    /**
     * 调用lua脚本实现秒杀
     * @param proId
     * @param uId
     * @return
     */
    public boolean secKillByScript(String proId,String uId){
        if ("".equals(proId) || null == proId ||"".equals(uId) || null == uId){
            return false;
        }

        Jedis jedis = RedisPoolUtil.getJedisPoolInstatnce().getResource();

        String script = jedis.scriptLoad(SecKillScript);
        Object evalsha = jedis.evalsha(script, 2, uId, proId);

        if ("0".equals(String.valueOf(evalsha))){
            System.out.println("未开始");
        }else if("1".equals(String.valueOf(evalsha))){
            System.out.println("已抢光");
        }else if("2".equals(String.valueOf(evalsha))){
            System.out.println("已秒杀");
        }else if("3".equals(String.valueOf(evalsha))){
            System.out.println("秒杀成功");
        }
        return  true;
    }
}