过度设计的产物……

不上 redis 还有个折衷的方法，额外生成一列 hash，生成索引，取 30 行列值>=随机生成的 hash 的就行了

插眼，优惠球踢

作为一个强迫症，每次拿到库都是先撸源代码，然后被前端大姐嫌弃，也经常被后端组长吐槽浪费时间。（最近修了一大堆前后端的祖传 bug 之后就没挨喷了）。跑题了不好意思

@feng32 多机的话，我的建议是用 redis 队列，看下官网的 list 文档说明

1. 单机环境下不应该用表，jdk 的信号量足够。
2. 乐观锁要手写插件： https://github.com/Dreamroute/locker

……，你先回答我官网文档你看完了吗 :D

:D 后端狗觉得用 java 很懒很爽，转 npm 后更彻底的成为废人了（指满世界的库）

卧槽，有没有镜像。

舌战群儒:D

给前端修 bug 的后台菜鸟路过。看描述估计是简单培训的，跟经理举发他（狗头）

谢谢，已经屏蔽

@Log
@RestController
@SpringBootApplication
public class WebApplication {

public static void main(String[] args) {
SpringApplication.run(WebApplication.class, args);
}

static final String CREATED = "create";
static final String PROCESS = "process";
static final String COMPLETE = "complete";


@PostMapping("generate")
public ResponseEntity<Response> generate(@RequestBody Request request) {
return ResponseEntity.ok(generate(request.input, request.taskId));
}


@Autowired
private RedisTemplate<Object, Object> redisTemplate;
@Autowired
private ThreadPoolTaskExecutor executor;

@PostConstruct
public void init() {
redisTemplate.setKeySerializer(RedisSerializer.string());
redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
}

Function<UUID, String> valKeyFunc = uuid -> "value::" + uuid;
Duration expire = Duration.ofMinutes(30L);

public Response generate(Integer input, UUID taskId) {

if (taskId == null) {
check(input != null, "请输入值");
UUID uuid = createTask(input);
return new Response(CREATED, null, uuid, expire.getSeconds());
}

String key = valKeyFunc.apply(taskId);
Long expire = redisTemplate.getExpire(key);
Entity value;
try {
value = (Entity) redisTemplate.opsForValue().get(key);
} catch (ClassCastException e) {
log.warning(e.getMessage());
e.printStackTrace();
throw new RuntimeException("服务器内部错误");
}
check(value != null, "任务 " + taskId + " 不存在或者已经过期");
assert value != null;
check(value.complete != null, "服务器内部错误");
if (!value.complete) {
return new Response(PROCESS, null, taskId, expire);
}

return new Response(COMPLETE, value, taskId, expire);
}


private static void check(Boolean condition, String msg) {
if (!Boolean.TRUE.equals(condition)) {
throw new RuntimeException(msg);
}
}


private UUID createTask(Integer input) {
UUID uuid = UUID.randomUUID();
executor.execute(() -> {
try {
Entity entity = new Entity(uuid, false, new Date(), null, input, null);
log.info(String.format("begin task: %s, input: %s", uuid, input));
String key = valKeyFunc.apply(uuid);
redisTemplate.opsForValue().set(key, entity, expire);
log.info(String.format("set task: %s, input: %s, key: %s", uuid, input, key));
TimeUnit.SECONDS.sleep(RandomUtil.randomInt(10, 20));
String value = RandomUtil.randomString(Math.abs(input));
entity.complete = true;
entity.completeTime = new Date();
entity.output = value;
log.info(String.format("end task: %s, input: %s, generated: %s", uuid, input, value));
redisTemplate.opsForValue().set(key, entity, expire);
} catch (InterruptedException e) {
log.warning(e.getMessage());
e.printStackTrace();
}
});
return uuid;
}

@Data
static class Request {
Integer input;
UUID taskId;
}

@AllArgsConstructor
@NoArgsConstructor
@Data
static class Response {
String status;
Object data;
UUID taskId;
Long expire;
}

@Data
@AllArgsConstructor
@NoArgsConstructor
static class Entity {
UUID taskId;
Boolean complete;
Date beginTime;
Date completeTime;

Integer input;
String output;
}

}

占坑#

啊，来晚了

@lemy 上周有过一个电话，说是送流量，我还特地问了很现在我手里的套餐有什么区别，他说不会有任何扣费^ ^