关于HashMap的深复制与浅复制

Java是不支持HashMap的深复制，如果想将一个HashMap中的元素深复制到另一个HashMap中只能一个实体一个实体复制过去。比如

public static HashMap<Integer, List<MySpecialClass>> copy(
    HashMap<Integer, List<MySpecialClass>> original)
{
    HashMap<Integer, List<MySpecialClass>> copy = new HashMap<Integer, List<MySpecialClass>>();
    for (Map.Entry<Integer, List<MySpecialClass>> entry : original.entrySet())
    {
        copy.put(entry.getKey(),
           // Or whatever List implementation you'd like here.
           new ArrayList<MySpecialClass>(entry.getValue()));
    }
    return copy;
}

参考https://stackoverflow.com/questions/28288546/how-to-copy-hashmap-not-shallow-copy-in-java/28288729