Java数组到ArrayList到数组

Question

I have an array name "asset" with 4 number. I then converted it to be stored in arraylist. Then with the arraylist copy to another array. Is this algorithm correct? After adding 5 the array should be able to show 5 number now

List assetList = new ArrayList();
String[] asset = {"1", "2", "3", "4"}; 

Collections.addAll(assetList, asset);

assetList.add("5");

String [] aListToArray = new String[assetList.size()];
aListToArray.toArray(aListToArray);

Answer 1

You need to change this line

aListToArray.toArray(aListToArray); // aListToArray to aListToArray itself? This would have given a compilation error

to this

assetList.toArray(aListToArray); // assetList to aListToArray is what you need.

Answer 2

仅使用Arrays.asList(asset);

Answer 3

You can make some simplifications:

List assetList = new ArrayList();
String[] asset = {"1", "2", "3", "4"}; 

assetList.addAll(asset);

assetList.add("5");

String [] aListToArray = assetList.toArray(aListToArray);

Overall, the code is correct. However if you want to have a "dynamic array", or a collection of items that changes in size, then don't bother trying to keep something in array form. An arraylist will work fine.