@RestController
public class NotifyController {

    @Autowired
    private Executor asyncExecutor;

    @PostMapping("/send-notify")
    public ResponseEntity<?> sendNotify(@RequestBody NotifyRequest request) {
        asyncExecutor.execute(() -> notifyService.send(request));
        return ResponseEntity.ok("已接收");
    }

    @Bean
    public Executor asyncExecutor() {
        return Executors.newFixedThreadPool(10);
    }
}

@Cacheable(value = "product", key = "#productId")
public Product getProductById(Long productId) {
    return productRepository.findById(productId).orElse(null);
}

@Aspect
@Component
public class RateLimitAspect {

    private final Map<String, Bucket> cache = new ConcurrentHashMap<>();

    @Around("@annotation(RateLimit)")
    public Object limit(ProceedingJoinPoint pjp) throws Throwable {
        String key = pjp.getSignature().toShortString();
        Bucket bucket = cache.computeIfAbsent(key, k -> Bucket4j.builder()
            .addLimit(Bandwidth.simple(100, Duration.ofSeconds(1)))
            .build());

        if (bucket.tryConsume(1)) {
            return pjp.proceed();
        } else {
            throw new RateLimitExceededException();
        }
    }
}

public class UserBatchService {

    private final LoadingCache<Long, CompletableFuture<User>> userCache = CacheBuilder.newBuilder()
        .refreshAfterWrite(10, TimeUnit.MILLISECONDS)
        .build(CacheLoader.asyncReloading(this::batchLoad, Executors.newFixedThreadPool(5)));

    private CompletableFuture<Map<Long, User>> batchLoad(Set<Long> userIds) {
        return CompletableFuture.supplyAsync(() -> userRepository.findByIds(userIds));
    }

    public CompletableFuture<User> getUser(Long id) {
        return userCache.get(id);
    }
}

@RestController
public class ReactiveProductController {

    @Autowired
    private ProductReactiveRepository repo;

    @GetMapping("/product/{id}")
    public Mono<Product> getProduct(@PathVariable String id) {
        return repo.findById(id);
    }
}

                    +------------------+
                    |   性能瓶頸分析   |
                    +------------------+
                             ↓
                +--------------------------+
                | 是 CPU 吞吐 還是 IO 阻塞？ |
                +--------------------------+
                             ↓
           +------------------------------------+
           | 線程池優(yōu)化 | 緩存 | 異步 | 限流 | 批處理 |
           +------------------------------------+