Java ArrayList和常用 數組間的相互轉換

public static void main(String[] args) {

Map<String, ArrayList<String>>  map = new HashMap<String, ArrayList<String>>();

ArrayList<String> arrayList = new ArrayList<String>();

arrayList.add("1");

arrayList.add("2");

map.put("A",arrayList);

 

//list轉數組

ArrayList<String> list  = map.get("A");

String [] strings = list.toArray(new String[list.size()]);

System.out.println(strings[1].toString());

 

//數組轉list 推薦下一行方法

//ArrayList<String> list2 = (ArrayList<String>) Arrays.asList(strings);

ArrayList<String> list2= new ArrayList<String>(Arrays.asList(strings));

System.out.println(list2.toString());