CaffeineCache自定义缓存时间

1、POM文件依赖

<dependency><groupId>com.github.ben-manes.caffeine</groupId><artifactId>caffeine</artifactId><version>3.1.0</version></dependency>

2、声明缓存

@Slf4j
public class CaffeineCacheUtils {/*** 声明缓存对象*/private static final Cache<String, Object> CACHE = Caffeine.newBuilder()// 当key和value都没有引用时驱逐缓存.weakKeys().weakValues()// 最大容量.maximumSize(10_000)// 固定存活时间24小时.expireAfterWrite(2 * 60 * 60 * 1000L, TimeUnit.MILLISECONDS).build()// 构建Caffeine缓存;}

3、缓存使用

/*** 添加缓存** @param key   key值* @param value value值*/public static void put(String key, Object value) {CACHE.put(key, value);}/*** 获取缓存对象** @param key key值* @return 返回value值*/public static Object get(String key) {return CACHE.getIfPresent(key);}

4、测试缓存

@Testpublic void testCache() {CaffeineCacheUtils.put("key", "value");Object value = CaffeineCacheUtils.get("key");log.info("value={}", value);}

5、自定义缓存过期时间

expireAfterWrite是指定一个固定的过期时间，如果想要根据不同的key值自己指定过期时间，可以按照下面的方法来实现。

声明一个缓存value值holder对象

@Data
public class CacheValueHolder implements Serializable {@Serialprivate static final long serialVersionUID = 1398783661313031605L;private Object value;private TimeUnit timeUnit;private long expire;}

创建缓存容器

/*** 声明缓存对象*/private static final Cache<String, CacheValueHolder> CACHE = Caffeine.newBuilder()// 当key和value都没有引用时驱逐缓存.weakKeys().weakValues()// 最大容量.maximumSize(10_000).expireAfter(new Expiry<String, CacheValueHolder>() {@Overridepublic long expireAfterCreate(String key, CacheValueHolder valueHolder, long currentTime) {log.info("创建缓存对象，key={}，value={}，currentTime={}", key, JSON.toJSONString(valueHolder), currentTime);return valueHolder.getTimeUnit().toNanos(valueHolder.getExpire());}@Overridepublic long expireAfterUpdate(String key, CacheValueHolder valueHolder, long currentTime, @NonNegative long currentDuration) {log.info("更新缓存对象，key={}，value={}，currentTime={}，currentDuration={}", key, JSON.toJSONString(valueHolder), currentTime, currentDuration);return valueHolder.getTimeUnit().toNanos(valueHolder.getExpire());}@Overridepublic long expireAfterRead(String key, CacheValueHolder valueHolder, long currentTime, @NonNegative long currentDuration) {log.info("读取缓存对象，key={}，value={}，currentTime={}，currentDuration={}", key, JSON.toJSONString(valueHolder), currentTime, currentDuration);return currentDuration;}})// 如果缓存不存在，则同步查询事业部产品列表，同时加入缓存.build()// 构建Caffeine缓存;

修改缓存使用方法

/*** 添加缓存** @param key      key值* @param value    value值* @param expire   过期时间* @param timeUnit 时间类型*/public static void put(String key, Object value, long expire, TimeUnit timeUnit) {CacheValueHolder valueHolder = new CacheValueHolder();valueHolder.setValue(value);valueHolder.setExpire(expire);valueHolder.setTimeUnit(timeUnit);CACHE.put(key, valueHolder);}/*** 添加缓存** @param key   key值* @param value value值*/public static void put(String key, Object value) {// 默认缓存存在时间为1000毫秒put(key, value, 1000, TimeUnit.MILLISECONDS);}/*** 获取缓存对象** @param key key值* @return 返回value值*/public static Object get(String key) {CacheValueHolder valueHolder = CACHE.getIfPresent(key);if (Objects.isNull(valueHolder)) {return null;}return valueHolder.getValue();}

6、测试自定义超时时间

@Testpublic void testCache() throws InterruptedException {CaffeineCacheUtils.put("key1", "value1", 1000L, TimeUnit.MILLISECONDS);CaffeineCacheUtils.put("key2", "value2", 2000L, TimeUnit.MILLISECONDS);Object value1 = CaffeineCacheUtils.get("key1");Object value2 = CaffeineCacheUtils.get("key2");log.info("value1={}", value1);log.info("value2={}", value2);TimeUnit.MILLISECONDS.sleep(1000L);Object value11 = CaffeineCacheUtils.get("key1");Object value22 = CaffeineCacheUtils.get("key2");log.info("value1={}", value11);log.info("value2={}", value22);}

方法运行后日志为：

23:44:21.398 [main] INFO com.summer.toolkit.util.CaffeineCacheUtils - 创建缓存对象，key=key1，value={"expire":1000,"timeUnit":"MILLISECONDS","value":"value1"}，currentTime=8165196876700
23:44:21.401 [main] INFO com.summer.toolkit.util.CaffeineCacheUtils - 创建缓存对象，key=key2，value={"expire":2000,"timeUnit":"MILLISECONDS","value":"value2"}，currentTime=8165240503500
23:44:21.401 [main] INFO com.summer.toolkit.util.CaffeineCacheUtils - 读取缓存对象，key=key1，value={"expire":1000,"timeUnit":"MILLISECONDS","value":"value1"}，currentTime=8165240686100，currentDuration=956190600
23:44:21.403 [main] INFO com.summer.toolkit.util.CaffeineCacheUtils - 读取缓存对象，key=key2，value={"expire":2000,"timeUnit":"MILLISECONDS","value":"value2"}，currentTime=8165242670700，currentDuration=1997832800
23:44:21.403 [main] INFO com.summer.toolkit.service.CaffeineCacheUtilsTest - value1=value1
23:44:21.403 [main] INFO com.summer.toolkit.service.CaffeineCacheUtilsTest - value2=value2
23:44:22.410 [main] INFO com.summer.toolkit.util.CaffeineCacheUtils - 读取缓存对象，key=key2，value={"expire":2000,"timeUnit":"MILLISECONDS","value":"value2"}，currentTime=8166249659500，currentDuration=990844000
23:44:22.411 [main] INFO com.summer.toolkit.service.CaffeineCacheUtilsTest - value1=null
23:44:22.412 [main] INFO com.summer.toolkit.service.CaffeineCacheUtilsTest - value2=value2

可以看到同时放入缓存容器中的两个缓存，一个1000毫秒的过期时间，一个2000毫秒的过期时间，当刚放入时都可以获取到，等待1000毫秒后，只有第二个缓存可以获取到，第一个缓存对象已经过期获取不到，实现了用户自定义缓存对象过期时间。