将hashmap的arraylist放入另一个

Question

I want to put an ArrayList<HashMap<String, Object>> into another ArrayList<HashMap<String, Object>> . How can I do that?

I was trying with the assignment operator ( = ) but I found out that it just points to the reference, I want to put the elements into another.

Answer 1

您可以使用addAll方法，但是请记住，它不会复制HashMaps，而且不会复制其中的Object！

Answer 2

Try this:

List<HashMap<String, Object>> newList = new ArrayList<HashMap<String,Object>>();
for (HashMap<String, Object> hm: oldList) {
    newList.add(hm);
}

Answer 3

You can create a new ArrayList Object and just call the addAll method and pass the ArrayList you want to copy

Another way is Collections.copy(desc,src) but this is not feasible since the size of both the List must be equal.