Guava Cache 。put（key，value）不向我的缓存添加值； put（）方法不起作用

Question

我有一个简单的缓存，用于通过IP存储Guava RateLimiter实例。请参见下面的代码块。 put（）调用不会将任何内容放入cache。在番石榴RateLimiter中存储Cache有一些限制吗？我明显缺少什么吗？

@Component
public class MyRateLimiter {

  public static final Logger LOGGER = LoggerFactory.getLogger(MyRateLimiter.class);
  public static long CACHE_SIZE = 1000L;
  public static long TIMEOUT = 10L;

  private static Cache<String, RateLimiter> cache = CacheBuilder.newBuilder()
        .maximumSize(CACHE_SIZE)
        .expireAfterWrite(TIMEOUT, TimeUnit.MINUTES)
        .build();

  public boolean tryAcquire(String key, double secondsBeforeNextOperation) {
      RateLimiter rateLimiter = cache.getIfPresent(key);
      if (rateLimiter == null) {
          rateLimiter = getNewRateLimiter(secondsBeforeNextOperation);
          cache.put(key, rateLimiter);  // <- This executes..
      }
      return rateLimiter.tryAcquire();  // <- But cache is still empty at breakpoint here
  }

  private RateLimiter getNewRateLimiter(double secondsBeforeNextOperation) {
      return RateLimiter.create(1 / secondsBeforeNextOperation);
  }

}

此代码碰巧在Spring Component中运行，但默认情况下为单例作用域，cache是静态的。此外，我在return rateLimiter.tryAcquire()行上设置了一个断点，并且cache仍然为空，即使刚执行cache.put()行之后的一行代码也是如此。

JVM是Java 8，我正在SpringBoot中运行。

---更新---

这是我使用tryAcquire()的get(K, Callable<V>)方法：

public boolean tryAcquire(String key, double secondsBeforeNextOperation) {
    RateLimiter rateLimiter = null;
    try {
        rateLimiter = cache.get(key, () ->
                getNewRateLimiter(secondsBeforeNextOperation));
    } catch (ExecutionException e) {
        LOGGER.warn("Throttling cache was not able to be read.");
        return false;
    }
    return rateLimiter.tryAcquire();  // <-- cache still empty at this breakpoint
}

Answer 1

确切地说，您如何确定断点注释所在行的缓存为空？我很想看看在同一位置打印/记录cache.asMap（）的值的结果。