code: public static <T> Reference<T> create(ReferenceType type, T referent, ReferenceQueue<T> queue) {
  		switch (type) {
  		case SOFT:
  			return new SoftReference<>(referent);
  		case WEAK:
  			return new WeakReference<>(referent);
  		case PHANTOM:
  			return new PhantomReference<T>(referent, queue);
  		default:
  			return null;
  		}
  	}
docs: 获得引用
  
  @param <T> 被引用对象类型
  @param type 引用类型枚举
  @param referent 被引用对象
  @param queue 引用队列
  @return {@link Reference}