利用lua保证Redis原子性

fruit这个key的值为100

开1000线程去抢

直接成负数了，👇未利用lua脚本

@GetMapping("/nosafe")
public String exhaustFruit() {
    ValueOperations operations = redisTemplate.opsForValue();
    Integer integer = Integer.valueOf(String.valueOf(operations.get("fruit")));
    if (integer < 1) {
        return "被抢完了";
    }
    operations.increment("fruit", -1);
    return "获得一个水果";
}

利用lua脚本来保证redis的原子性👇

String lua = "local current = redis.call('get', 'fruit')\n" +
    "if tonumber(current) > 0 then\n" +
    "  redis.call('decr', 'fruit')\n" +
    "  return 1\n" +
    "end\n" +
    "return 0\n";

@GetMapping("/safe")
public String exhaustFruitWithLuaScript() {
    RedisScript longDefaultRedisScript = new DefaultRedisScript(lua, Long.class);
    Integer execute = Integer.valueOf(String.valueOf(redisTemplate.execute(longDefaultRedisScript, null, "1")));
    if (execute == 1) {
        return "获得一个水果";
    }
    return "被抢完了";
}