网站建设运转,wordpress酒店,郑州比较好的设计公司,怎样自己做免费网站1. 功能#xff1a; map 线程安全#xff0c;能够对存入的数据设置过期#xff0c;或者自定义删除
2. aliyun代码看到的一个对象正好符合上述需求 出处是aliyun sdk core jar包的一个类。感兴趣可以去下载下jar查看
下面是源码#xff1a;
package com.aliyuncs.policy.…1. 功能 map 线程安全能够对存入的数据设置过期或者自定义删除
2. aliyun代码看到的一个对象正好符合上述需求 出处是aliyun sdk core jar包的一个类。感兴趣可以去下载下jar查看
下面是源码
package com.aliyuncs.policy.cache;import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.commons.lang3.concurrent.BasicThreadFactory;public class ThrottlingPool {private static final MapString, Entity map new ConcurrentHashMap();private static final ScheduledExecutorService executor new ScheduledThreadPoolExecutor(1, (new BasicThreadFactory.Builder()).namingPattern(throttling-pool-%d).daemon(true).build());public ThrottlingPool() {}public static synchronized void put(String key, Object data) {put(key, data, -1);}public static synchronized void put(final String key, Object data, int expire) {remove(key);if (data ! null) {if (expire 0) {Future future executor.schedule(new Runnable() {public void run() {synchronized(ThrottlingPool.class) {ThrottlingPool.map.remove(key);}}}, (long)expire, TimeUnit.MILLISECONDS);map.put(key, new Entity(data, expire, future));} else {map.put(key, new Entity(data, expire, (Future)null));}}}public static synchronized Object get(String key) {Entity entity (Entity)map.get(key);return entity ! null ? entity.getValue() : null;}public static synchronized T T get(String key, ClassT clazz) {return (T)clazz.cast(get(key));}public static synchronized int getExpire(String key) {Entity entity (Entity)map.get(key);return entity ! null ? entity.getExpire() : 0;}public static synchronized Object remove(String key) {Entity entity (Entity)map.remove(key);if (entity null) {return null;} else {Future future entity.getFuture();if (future ! null) {future.cancel(true);}return entity.getValue();}}public static synchronized int size() {return map.size();}public static synchronized void clear() {for(Entity entity : map.values()) {if (entity ! null) {Future future entity.getFuture();if (future ! null) {future.cancel(true);}}}map.clear();}public static synchronized MapString, Entity getPool() {return map;}private static class Entity {private Object value;private int expire;private Future future;public Entity(Object value, int expire, Future future) {this.value value;this.expire expire;this.future future;}public Object getValue() {return this.value;}public int getExpire() {return this.expire;}public Future getFuture() {return this.future;}}
}2. 但是有个问题如果数据量大且都设置有过期时间容易过期不及时单线程处理不过来
3. 下面代码采用延迟队列一版
import java.util.concurrent.*;public class ThrottlingPool {private static final ConcurrentHashMapString, Object map new ConcurrentHashMap();private static final DelayQueueDelayedCacheEntry delayQueue new DelayQueue();private static final ExecutorService executor Executors.newSingleThreadExecutor(r - {Thread t new Thread(r);t.setDaemon(true);return t;});public static void put(String key, Object data, long expireMs) {long expirationTime System.currentTimeMillis() expireMs;delayQueue.removeIf(entry - entry.getKey().equals(key));map.put(key, data);delayQueue.offer(new DelayedCacheEntry(key, expirationTime));}public static Object get(String key) {return map.get(key);}public static void remove(String key) {map.remove(key);}public static int size() {return map.size();}// 启动一个后台线程处理过期任务static {executor.execute(() - {while (!Thread.currentThread().isInterrupted()) {try {DelayedCacheEntry entry delayQueue.take();
// synchronized (ThrottlingPool.class) {map.remove(entry.getKey());
// }} catch (InterruptedException ex) {ex.printStackTrace();Thread.currentThread().interrupt();break;}}});// 钩子Runtime.getRuntime().addShutdownHook(new Thread(() - {executor.shutdown();}));
// Thread cleanupThread new Thread(() - {
// while (true) {
// try {
// DelayedCacheEntry entry delayQueue.take();
// synchronized (ThrottlingPool.class) {
// map.remove(entry.getKey());
// }
// } catch (InterruptedException e) {
// Thread.currentThread().interrupt();
// break;
// }
// }
// });
// cleanupThread.setDaemon(true);
// cleanupThread.start();}private static class DelayedCacheEntry implements Delayed {private final String key;private final long expirationTime;public DelayedCacheEntry(String key, long expirationTime) {this.key key;this.expirationTime expirationTime;}Overridepublic long getDelay(TimeUnit unit) {long diff expirationTime - System.currentTimeMillis();return unit.convert(diff, TimeUnit.MILLISECONDS);}Overridepublic int compareTo(Delayed o) {return Long.compare(this.expirationTime, ((DelayedCacheEntry) o).expirationTime);}public String getKey() {return key;}}}
4.本人水平有限如有问题欢迎指正
