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<Object> 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<HostAndPort> set=new HashSet<HostAndPort>();

  //  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;
  }
}