重用咖啡因缓存键

Question

我已经使用 caffeine 实现了 cache。我希望它在 1 day 后过期，而且效果很好。问题是，如果我尝试使用修改后的查询（根据参数值进行修改）从 cache 获取数据，我总是会得到相同的结果。只有当我使用相同的参数值（例如相同的日期范围）执行查询时，我才想获得相同的结果。我的理解是我不应该重复使用相同的 cache-key，但我不确定如何不这样做。这是实现：

@Service
public class SomeServiceImpl implements SomeService {
  private static final String CACHE_KEY = "some-key";
  private Cache<String, List<SomeVO>> someCache;



  public RecentHighestSlotWinsServiceImpl() {

    someCache= Caffeine.newBuilder().maximumSize(100).expireAfterWrite(1, TimeUnit.DAYS).build();
  }

  @Override
  public List<SomeVO> checkCacheForData(Instant startDate, Instant endDate) {

  List<SomeVO> someList= someCache.getIfPresent(CACHE_KEY);
  if (someList!= null) {
      return someList;
  } else {
      log.info("Loading from DB ");
      List<SomeVO> templateResult= getData(startDate, endDate);
      if (templateResult.isSuccessAndNotNull()) {
          someCache.put(CACHE_KEY, Objects.requireNonNull(templateResult.getData()));
      }
      return templateResult;
  }
}

Answer 1

处理此问题的几种方法：

正如@Louis Wasserman 提到的，有这样的事情：

import java.time.Instant;
import java.util.Objects;

public class CacheKey {
  private Instant startDate;
  private Instant endDate;

  public CacheKey() {
  }

  public CacheKey(Instant startDate, Instant endDate) {
    this.startDate = startDate;
    this.endDate = endDate;
  }

  public Instant getStartDate() {
    return startDate;
  }

  public void setStartDate(Instant startDate) {
    this.startDate = startDate;
  }

  public Instant getEndDate() {
    return endDate;
  }

  public void setEndDate(Instant endDate) {
    this.endDate = endDate;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o)
      return true;
    if (o == null || getClass() != o.getClass())
      return false;
    CacheKey cacheKey = (CacheKey) o;
    return Objects.equals(startDate, cacheKey.startDate) &&
        Objects.equals(endDate, cacheKey.endDate);
  }

  @Override
  public int hashCode() {
    return Objects.hash(startDate, endDate);
  }
}

并在您的方法 checkCacheForData 中使用：

@Service
public class SomeServiceImpl implements SomeService {
  private Cache<CacheKey, List<SomeVO>> someCache;



  public RecentHighestSlotWinsServiceImpl() {

    someCache= Caffeine.newBuilder().maximumSize(100).expireAfterWrite(1, TimeUnit.DAYS).build();
  }

  @Override
  public List<SomeVO> checkCacheForData(Instant startDate, Instant endDate) {

  List<SomeVO> someList= someCache.getIfPresent(new CacheKey(startDate,endDate));
  if (someList!= null) {
      return someList;
  } else {
      log.info("Loading from DB ");
      List<SomeVO> templateResult= getData(startDate, endDate);
      if (templateResult.isSuccessAndNotNull()) {
          someCache.put(new CacheKey(startDate,endDate), Objects.requireNonNull(templateResult.getData()));
      }
      return templateResult;
  }
}

您可以连接开始日期和结束日期的字符串表示并将其用作缓存键，而不是拥有单独的对象。

@Service
public class SomeServiceImpl implements SomeService {
  private Cache<String, List<SomeVO>> someCache;



  public RecentHighestSlotWinsServiceImpl() {

    someCache= Caffeine.newBuilder().maximumSize(100).expireAfterWrite(1, TimeUnit.DAYS).build();
  }

  @Override
  public List<SomeVO> checkCacheForData(Instant startDate, Instant endDate) {

String cacheKey = startDate.toString() + endDate.toString();
  List<SomeVO> someList= someCache.getIfPresent(cacheKey);
  if (someList!= null) {
      return someList;
  } else {
      log.info("Loading from DB ");
      List<SomeVO> templateResult= getData(startDate, endDate);
      if (templateResult.isSuccessAndNotNull()) {
          someCache.put(cacheKey, Objects.requireNonNull(templateResult.getData()));
      }
      return templateResult;
  }
}

重用咖啡因缓存键

Reuse caffeine cache key

java

spring

java-8

spring-boot

caffeine