咖啡因缓存刷新/重新加载缓存手动或按需

Question

我已经在我的应用程序中实现了咖啡因缓存。我正在从几个静态表中缓存数据。但是我想知道我是否可以使用 REST API 或任何其他方式手动或按需刷新/清除/重新加载缓存。 任何人都可以提出实施这种要求的方法吗？

我想要这样的东西：- 一个端点网址，如：- http://localhost:8080/refreshCache

这将在内部触发某些方法并手动清除缓存或重新加载缓存中的新值。

以下是缓存配置：

@Configuration
public class CacheConfig{
private com.github.benmanes.caffeine.cache.Cache<Object, Object> cache;
@Bean
Caffeine<Object,Object> cacheBuilder(){
return Caffeine.newBuilder()
.initialCapacity(300)
.maximumSize(50000)
.expireAfterAccess(1, TimeUnit.DAYS)
.removalListener(new CacheRemovalListener())
.recordStats();
}
class CacheRemovalListener implements RemovalListener<Object, Object> {
@Override
public void onRemoval(Object key, Object value, RemovalCause cause) {
System.out.format("Removal listener called with key [%s], cause[%s], evicted [%s] %n", 
key , cause.toString(), cause.wasEvicted());
}
}
} 

Answer 1

您可以使用Spring的CacheManager创建CaffeineCache实例，然后可以使用CacheManager对任何缓存执行CRUD操作。

请参阅下面的代码。

Bean 配置：

public class CacheBeansConfig {
@Bean
public CacheManager cacheManager() {
// create multiple instances of cache
CaffeineCacheManager cacheManager = new CaffeineCacheManager("UserCache","InventoryCache");
cacheManager.setCaffeine(caffeineCacheBuilder());
return cacheManager;
}
private Caffeine<Object, Object> caffeineCacheBuilder() {
return Caffeine.newBuilder()
.initialCapacity(<initial capacity>)
.maximumSize(<max size>)
.expireAfterAccess(<expire after hrs>, TimeUnit.HOURS)
.recordStats();
}

这将使用两个 Caffeeine 缓存实例初始化您的 CacheManager。

使用下面的 Rest 控制器类来访问这些类。

@RestController
@RequestMapping(path = "/v1/admin/cache")
public class ACSCacheAdminController {
@Autowired
private CacheManager cacheManager;
/**
* call this to invalidate all cache instances
*/
@DeleteMapping(
path = "/",
produces = {"application/json"})
public void invalidateAll() {
Collection<String> cacheNames = cacheManager.getCacheNames();
cacheNames.forEach(this::getCacheAndClear);
}
/**
* call this to invalidate a given cache name
*/
@DeleteMapping(
path = "/{cacheName}",
produces = {"application/json"})
public void invalidateCache(@PathVariable("cacheName") final String cacheName) {
getCacheAndClear(cacheName);
}
/**
* Use this to refresh a cache instance
*/
@PostMapping(
path = "/{cacheName}",
produces = {"application/json"})
public void invalidateCache(@PathVariable("cacheName") final String cacheName) {
getCacheAndClear(cacheName);
Cache cache = cacheManager.getCache(cacheName);
// your logic to put in above cache instance
// use cache.put(key,value)
}

/**
* call this to invalidate cache entry by given cache name and cache key
*/
@DeleteMapping(
path = "/{cacheName}/{key}/",
produces = {"application/json"})
public void invalidateCacheKey(
@PathVariable("cacheName") final String cacheName, @PathVariable("key") Object key) {
final Cache cache = cacheManager.getCache(cacheName);
if (cache == null) {
throw new IllegalArgumentException("invalid cache name for key invalidation: " + cacheName);
}
cache.evict(key);
}
@GetMapping(
path = "/{cacheName}/{key}",
produces = {"application/json"})
public ResponseEntity<Object> getByCacheNameAndKey(
@PathVariable("cacheName") final String cacheName, @PathVariable("key") final int key) {
final Cache cache = cacheManager.getCache(cacheName);
if (cache == null) {
throw new IllegalArgumentException("invalid cache name: " + cacheName);
}
return ResponseEntity.ok().body(cache.get(key));
}
private void getCacheAndClear(final String cacheName) {
final Cache cache = cacheManager.getCache(cacheName);
if (cache == null) {
throw new IllegalArgumentException("invalid cache name: " + cacheName);
}
cache.clear();
}

只需根据需要更改代码即可:)