在Java中实现缓存的几种方式包括：
- 使用
HashMap：
public class Cache<K, V> {
private final Map<K, V> cache = new HashMap<>();
public V get(K key) {
return cache.get(key);
}
public void put(K key, V value) {
cache.put(key, value);
}
}
- 使用
Guava Cache：
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
public class GuavaCacheExample {
private static final LoadingCache<String, String> cache = CacheBuilder.newBuilder()
.maximumSize(1000)
.expireAfterWrite(10, TimeUnit.MINUTES)
.build(new CacheLoader<String, String>() {
@Override
public String load(String key) throws Exception {
return fetchDataFromDatabase(key);
}
});
public static String get(String key) {
try {
return cache.get(key);
} catch (ExecutionException e) {
e.printStackTrace();
return null;
}
}
private static String fetchDataFromDatabase(String key) {
// 从数据库获取数据
return "data";
}
}
- 使用
Ehcache：
import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Element;
public class EhCacheExample {
private static final CacheManager cacheManager = CacheManager.newInstance();
private static final Cache cache = cacheManager.getCache("myCache");
public static String get(String key) {
Element element = cache.get(key);
return element != null ? (String) element.getObjectValue() : null;
}
public static void put(String key, String value) {
cache.put(new Element(key, value));
}
}
- 使用
Caffeine：
import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
public class CaffeineCacheExample {
private static final Cache<String, String> cache = Caffeine.newBuilder()
.maximumSize(1000)
.expireAfterWrite(10, TimeUnit.MINUTES)
.build();
public static String get(String key) {
return cache.get(key, k -> fetchDataFromDatabase(key));
}
private static String fetchDataFromDatabase(String key) {
// 从数据库获取数据
return "data";
}
}
这些方式可以实现不同层次的缓存需求，从简单的HashMap到复杂的分布式缓存解决方案如Ehcache和\`Caffeine