oscache使用经历
oscache作为一款老的本地缓存，应用场景主要有页面缓存和对象缓存。这里拿在maven项目中使用oscache作为对象缓存举例说明下用法：
1、导入jar包
<dependency> <groupId>opensymphony</groupId> <artifactId>oscache</artifactId> <version>2.4.1</version> </dependency>
2、在resources目录下新增配置文件oscache.properties
# CACHE IN MEMORY
#
# If you want to disable memory caching, just uncomment this line.
#
cache.memory=true
# CACHE SIZE
#
# Default cache size in number of items. If a size is specified but not
# an algorithm, the cache algorithm used will be LRUCache.
#
cache.capacity=100000
# CACHE LISTENERS
#
# These hook OSCache events and perform various actions such as logging
# cache hits and misses, or broadcasting to other cache instances across a cluster.
# See the documentation for further information.
#
# com.opensymphony.oscache.extra.CacheEntryEventListenerImpl
# CACHE ALGORITHM
#
# Default cache algorithm to use. Note that in order to use an algorithm
# the cache size must also be specified. If the cache size is not specified,
# the cache algorithm will be Unlimited cache.
#
#cache.algorithm=com.opensymphony.oscache.base.algorithm.LRUCache
cache.algorithm=com.opensymphony.oscache.base.algorithm.FIFOCache
# THREAD BLOCKING BEHAVIOR
#
# When a request is made for a stale cache entry, it is possible that another thread is already
# in the process of rebuilding that entry. This setting specifies how OSCache handles the
# subsequent 'non-building' threads. The default behaviour (cache.blocking=false) is to serve
# the old content to subsequent threads until the cache entry has been updated. This provides
# the best performance (at the cost of serving slightly stale data). When blocking is enabled,
# threads will instead block until the new cache entry is ready to be served. Once the new entry
# is put in the cache the blocked threads will be restarted and given the new entry.
# Note that even if blocking is disabled, when there is no stale data available to be served
# threads will block until the data is added to the cache by the thread that is responsible
# for building the data.
#
# cache.blocking=false
# JAVAGROUPS CLUSTER PROPERTIES
#
# Configuration properites for the JavaGroups clustering. Only one of these
# should be specified. Default values (as shown below) will be used if niether
# property is set. See the clustering documentation and the JavaGroups project
# (www.javagroups.com) for more information on these settings.
#
#cache.cluster.properties=UDP(singleton_name\=screenWidthAdapter;tos\=8;mcast_addr\=225.90.21.10;mcast_port\=50103;mcast_send_buf_size\=640K;mcast_recv_buf_size\=25M;ip_ttl\=32;loopback\=true;discard_incompatible_packets\=true;enable_bundling\=true;max_bundle_size\=64K;max_bundle_timeout\=30;enable_diagnostics\=true;thread_naming_pattern\=book;timer.num_threads\=4;thread_pool.enabled\=true;thread_pool.min_threads\=2;thread_pool.max_threads\=8;thread_pool.keep_alive_time\=5000;thread_pool.queue_enabled\=true;thread_pool.queue_max_size\=10000;thread_pool.rejection_policy\=discard;oob_thread_pool.enabled\=true;oob_thread_pool.min_threads\=1;oob_thread_pool.max_threads\=8;oob_thread_pool.keep_alive_time\=5000;oob_thread_pool.queue_enabled\=false;oob_thread_pool.queue_max_size\=100;oob_thread_pool.rejection_policy\=Run)\:PING(timeout\=2000;num_initial_members\=3)\:MERGE2(min_interval\=10000;max_interval\=30000)\:FD(timeout\=20000;max_tries\=9)\:FD_SOCK()\:FD_ALL()\:VERIFY_SUSPECT(timeout\=15000)\:BARRIER()\:pbcast.NAKACK(retransmit_timeout\=300,600,1200,2400,4800,9600,19200;use_mcast_xmit\=true;use_stats_for_retransmission\=true;xmit_history_max_size\=500;max_rebroadcast_timeout\=20000;discard_delivered_msgs\=false;gc_lag\=500;use_stats_for_retransmission\=false;exponential_backoff\=0)\:UNICAST(timeout\=300,600,1200,2400,4800,9600,19200)\:pbcast.STABLE(stability_delay\=1000;desired_avg_gossip\=20000;max_bytes\=1M)\:pbcast.GMS(join_timeout\=3000;print_local_addr\=true;view_bundling\=true)\:FC(max_credits\=500K;min_threshold\=0.20;ignore_synchronous_response\=true)\:FRAG2(frag_size\=60K)\:pbcast.STATE_TRANSFER()
3、新增缓存类
package com.wlf.net.point.cache; import java.math.BigDecimal; import java.util.Date; import java.util.concurrent.atomic.AtomicLong; import java.util.logging.Logger; import com.opensymphony.oscache.base.NeedsRefreshException; import com.opensymphony.oscache.general.GeneralCacheAdministrator; import com.opensymphony.oscache.web.filter.ExpiresRefreshPolicy; /** * 本地缓存 * * @author wulf * @since 2018年3月28日*/ public class OsCache extends GeneralCacheAdministrator { private static final Logger LOG = Logger.getLogger("OsCache"); /** * 序列化ID */ private static final long serialVersionUID = -3814537980571610987L; // 缓存命中次数 private AtomicLong hitCount = new AtomicLong(0L); // 总请求次数 private AtomicLong reqCount = new AtomicLong(0L); // 命中率 private double hitRate = 0D; private static final OsCache cache = new OsCache(); /** * 单例 */ public static OsCache getInstance() { return cache; } /** * 从OSCACHE中获取原始缓存数据 * * @param key 缓存KEY值 * @param refreshTime 失效时间，-1时为永久缓存 * @return 原始缓存数据 */ public Object get(String key, int refreshTime) { reqCount.incrementAndGet(); Object obj = null; try { obj = this.getFromCache(key, refreshTime); hitCount.incrementAndGet(); } catch (NeedsRefreshException e) { this.cancelUpdate(key); LOG.warning(e.getMessage()); } return obj; } /** * 从OSCACHE中获取原始缓存数据 * * @param key 缓存KEY值 * @param value Object 内容对象 * @param refreshTime 失效时间，-1时为永久缓存 * @return 原始缓存数据 */ public void put(String key, Object value, int refreshTime) { if (refreshTime == -1) { this.putInCache(key, value); } else { this.putInCache(key, value, new ExpiresRefreshPolicy(refreshTime)); } } /** * 从OSCACHE中删除缓存数据 * * @param key 缓存KEY值 */ public void remove(String key) { this.removeEntry(key); } /** * 从OSCACHE中删除所有缓存数据 * * @param date 预定删除时间 */ public void removeAll(Date date) { if (date == null) { this.flushAll(); } else { this.flushAll(date); } } /** * 获取命中率 * * @return */ public double getHitRate() { if (reqCount.longValue() == 0L) { return 0; } hitRate = (double)hitCount.longValue() / reqCount.longValue(); BigDecimal bd = new BigDecimal(hitRate); bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP); return bd.doubleValue(); } }
4、使用缓存主方法
public static void main(String[] args) { User user = (User)OsCache.getInstance().get("user_", -1); if(user != null) { LOG.info(user.toString()); } else { LOG.info("no user."); user = new User(); user.setName("wulf"); user.setAge(34); user.setSex(1); OsCache.getInstance().put("user_", user, -1); user = (User)OsCache.getInstance().get("user_", -1); LOG.info(user.toString()); }
5、执行主方法结果
三月 28, 2018 9:12:48 下午 com.opensymphony.oscache.base.Config loadProperties 信息: OSCache: Getting properties from URL file:/E:/workspace/TeaPot/target/classes/oscache.properties for the default configuration 三月 28, 2018 9:12:48 下午 com.opensymphony.oscache.base.Config loadProperties 信息: OSCache: Properties read {cache.algorithm=com.opensymphony.oscache.base.algorithm.FIFOCache, cache.capacity=100000, cache.memory=true} 三月 28, 2018 9:12:48 下午 com.opensymphony.oscache.general.GeneralCacheAdministrator <init> 信息: Constructed GeneralCacheAdministrator() 三月 28, 2018 9:12:48 下午 com.opensymphony.oscache.general.GeneralCacheAdministrator createCache 信息: Creating new cache 三月 28, 2018 9:12:48 下午 com.wlf.net.point.cache.OsCache get 警告: null 三月 28, 2018 9:12:48 下午 com.wlf.net.point.App main 信息: no user. 三月 28, 2018 9:12:48 下午 com.wlf.net.point.App main 信息: User [name=wulf, sex=1, age=34]
