weixin4j-base:获取cache时加锁处理(via 风车车)

CHANGE.md

@@ -736,3 +736,5 @@
 * 2016-07-22
 
   + weixin4j-base:主要调整退款相关类与官网一致
+  
+  + weixin4j-base:获取cache时加锁处理(via 风车车)

weixin4j-base/src/main/java/com/foxinmy/weixin4j/cache/CacheManager.java

@@ -1,5 +1,8 @@
 package com.foxinmy.weixin4j.cache;
 
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
+
 import com.foxinmy.weixin4j.exception.WeixinException;
 
 /**
@@ -14,6 +17,7 @@ import com.foxinmy.weixin4j.exception.WeixinException;
 public class CacheManager<T extends Cacheable> {
 	protected final CacheCreator<T> cacheCreator;
 	protected final CacheStorager<T> cacheStorager;
+	private final ReentrantLock lock = new ReentrantLock();
 
 	public CacheManager(CacheCreator<T> cacheCreator,
 			CacheStorager<T> cacheStorager) {
@@ -30,10 +34,21 @@ public class CacheManager<T extends Cacheable> {
 	public T getCache() throws WeixinException {
 		String cacheKey = cacheCreator.key();
 		T cache = cacheStorager.lookup(cacheKey);
+		try {
+			if (cache == null && lock.tryLock(3, TimeUnit.SECONDS)) {
+				try {
+					cache = cacheStorager.lookup(cacheKey);
 					if (cache == null) {
 						cache = cacheCreator.create();
 						cacheStorager.caching(cacheKey, cache);
 					}
+				} finally {
+					lock.unlock();
+				}
+			}
+		} catch (InterruptedException e) {
+			throw new WeixinException("get cache error on lock", e);
+		}
 		return cache;
 	}