@SuppressWarnings("unchecked")
        public <T> Constructor<T> get(ClassLoader classLoader, String className) {
            Assert.notNull(className, "className");
            ConcurrentMap<String, WeakReference<Constructor>> innerCache = cache.get(classLoader);
            if (innerCache == null) {
                return null;
            }
            WeakReference<Constructor> reference = innerCache.get(className);
            Constructor constructor = reference == null ? null : reference.get();
            if (reference != null && constructor == null) {
                innerCache.remove(className);
            }
            return (Constructor<T>) constructor;
        }
@author Robert HG (254963746@qq.com)on 12/23/15.
lts-core/src/main/java/com/github/ltsopensource/core/spi/ClassLoaderUtil.java