详解利用redis + lua解决抢红包高并发的问题

-- 函数：尝试获得红包，如果成功，则返回json字符串，如果不成功，则返回空 
-- 参数：红包队列名， 已消费的队列名，去重的Map名，用户ID 
-- 返回值：nil 或者 json字符串，包含用户ID：userId，红包ID：id，红包金额：money 
 
-- 如果用户已抢过红包，则返回nil 
if rediscall('hexists', KEYS[3], KEYS[4]) ~= 0 then 
 return nil 
else 
 -- 先取出一个小红包 
 local hongBao = rediscall('rpop', KEYS[1]); 
 if hongBao then 
  local x = cjsondecode(hongBao); 
  -- 加入用户ID信息 
  x['userId'] = KEYS[4]; 
  local re = cjsonencode(x); 
  -- 把用户ID放到去重的set里 
  rediscall('hset', KEYS[3], KEYS[4], KEYS[4]); 
  -- 把红包放到已消费队列里 
  rediscall('lpush', KEYS[2], re); 
  return re; 
 end 
end 
return nil 

public class TestEval { 
  static String host = "localhost"; 
  static int honBaoCount = 1_0_0000; 
   
  static int threadCount = 20; 
   
  static String hongBaoList = "hongBaoList"; 
  static String hongBaoConsumedList = "hongBaoConsumedList"; 
  static String hongBaoConsumedMap = "hongBaoConsumedMap"; 
   
  static Random random = new Random(); 
   
// -- 函数：尝试获得红包，如果成功，则返回json字符串，如果不成功，则返回空 
// -- 参数：红包队列名， 已消费的队列名，去重的Map名，用户ID 
// -- 返回值：nil 或者 json字符串，包含用户ID：userId，红包ID：id，红包金额：money 
  static String tryGetHongBaoScript =  
//     "local bConsumed = rediscall('hexists', KEYS[3], KEYS[4]);\n" 
//     + "print('bConsumed:' ,bConsumed);\n" 
      "if rediscall('hexists', KEYS[3], KEYS[4]) ~= 0 then\n" 
      + "return nil\n" 
      + "else\n" 
      + "local hongBao = rediscall('rpop', KEYS[1]);\n" 
//     + "print('hongBao:', hongBao);\n" 
      + "if hongBao then\n" 
      + "local x = cjsondecode(hongBao);\n" 
      + "x['userId'] = KEYS[4];\n" 
      + "local re = cjsonencode(x);\n" 
      + "rediscall('hset', KEYS[3], KEYS[4], KEYS[4]);\n" 
      + "rediscall('lpush', KEYS[2], re);\n" 
      + "return re;\n" 
      + "end\n" 
      + "end\n" 
      + "return nil"; 
  static StopWatch watch = new StopWatch(); 
   
  public static void main(String[] args) throws InterruptedException { 
//   testEval(); 
    generateTestData(); 
    testTryGetHongBao(); 
  } 
   
  static public void generateTestData() throws InterruptedException { 
    Jedis jedis = new Jedis(host); 
    jedisflushAll(); 
    final CountDownLatch latch = new CountDownLatch(threadCount); 
    for(int i = 0; i < threadCount; ++i) { 
      final int temp = i; 
      Thread thread = new Thread() { 
        public void run() { 
          Jedis jedis = new Jedis(host); 
          int per = honBaoCount/threadCount; 
          JSONObject object = new JSONObject(); 
          for(int j = temp * per; j < (temp+1) * per; j++) { 
            objectput("id", j); 
            objectput("money", j); 
            jedislpush(hongBaoList, objecttoJSONString()); 
          } 
          latchcountDown(); 
        } 
      }; 
      threadstart(); 
    } 
    latchawait(); 
  } 
   
  static public void testTryGetHongBao() throws InterruptedException { 
    final CountDownLatch latch = new CountDownLatch(threadCount); 
    Systemerrprintln("start:" + SystemcurrentTimeMillis()/1000); 
    watchstart(); 
    for(int i = 0; i < threadCount; ++i) { 
      final int temp = i; 
      Thread thread = new Thread() { 
        public void run() { 
          Jedis jedis = new Jedis(host); 
          String sha = jedisscriptLoad(tryGetHongBaoScript); 
          int j = honBaoCount/threadCount * temp; 
          while(true) { 
            Object object = jediseval(tryGetHongBaoScript, 4, hongBaoList, hongBaoConsumedList, hongBaoConsumedMap, "" + j); 
            j++; 
            if (object != null) { 
//             Systemoutprintln("get hongBao:" + object); 
            }else { 
              //已经取完了 
              if(jedisllen(hongBaoList) == 0) 
                break; 
            } 
          } 
          latchcountDown(); 
        } 
      }; 
      threadstart(); 
    } 
     
    latchawait(); 
    watchstop(); 
     
    Systemerrprintln("time:" + watchgetTotalTimeSeconds()); 
    Systemerrprintln("speed:" + honBaoCount/watchgetTotalTimeSeconds()); 
    Systemerrprintln("end:" + SystemcurrentTimeMillis()/1000); 
  } 
}