Redis在springboot的应用场景

场景一：出入库存量——分布锁

1.  锁是共享的
2. Callable回调返回结果会抛出异常。Runable不会抛出异常
3. k打进去==能获取到锁
4. 自定义线程
5. mysql并发超过2000就会跟慢，要把压力传给给Redis。这样的场景有秒杀、

场景二：秒杀

         lua脚本是将string转换成二进制。转换成二进制之前，数字要先强转成数字；且使用多行lua脚本使用stringBuilder（）方法；双引号加空号，符号加空格；否则两个单词会默认成一个，识别不了

 1 @SpringBootTest
 2 public class DockerTest {
 3     @Resource(name="redisTemplate")
 4     private ValueOperations<String,Integer> valueOperations;
 5     @Autowired
 6     private StringRedisTemplate stringRedisTemplate;
 7     @Test //初始化 Redis库存量
 8     void test() throws IOException {
 9         valueOperations.set("producthh",20);
10     }
11 
12     @Test
13     void Test111() throws IOException {
14         ExecutorService executorService = Executors.newCachedThreadPool();
15         StringBuilder letter = new StringBuilder();
16         letter.append(" local qty1 = redis.call('get',KEYS[1]) ");
17         letter.append(" local qty2 = ARGV[1] ");
18         letter.append(" if (tonumber(qty1) >= tonumber(qty2)) ");
19         letter.append(" then   ");
20         letter.append("  redis.call('decrby',KEYS[1],qty2) ");
21         letter.append(" return -1 ");
22         letter.append(" else ");
23         letter.append(" return  tonumber(qty1) ");
24         letter.append(" end ");
25         RedisScript<Long> script = RedisScript.of(letter.toString(), Long.class);
26         for (int i = 1; i < 10; i++) {
27             int finalI = i;
28             executorService.execute(() -> {
29                 int qty = RandomUtil.randomInt(1, 20);
30                 Long ret = stringRedisTemplate.execute(script, CollUtil.newArrayList(key), String.valueOf(qty));
31                 if (ret == -1) {
32                     System.out.println(finalI + "扣减成功->" + qty);
33                 } else {
34                     System.out.println("失败，需要：" + qty + " 剩余库存:" + ret);
35                 }
36             });
37 
38 
39         }
40 
41         ThreadUtil.safeSleep(10000);
42 
43 
44     }
45 
46 }