Integer 类型
ArrayList<Integer> Mlist = new ArrayList<Integer>();
Scanner scM = new Scanner(new File("D://m.txt"));
while (scM.hasNextInt()) {
int i = scM.nextInt();
Mlist.add(i);
}
/*将list转为数组*/
Integer[] Marray = new Integer[Mlist.size()];
Marray = (Integer[])Mlist.toArray(Marray);
String 类型
ArrayList<String> Nlist = new ArrayList<String>();
Scanner scN = new Scanner(new File("D://n.txt"));
while (scN.hasNextLine()) {
String i = scN.nextLine();
Nlist.add(i);
}
/*将list转为数组*/
String[] Narray = new String[Nlist.size()];
Narray = (String[])Nlist.toArray(Narray);
/*数组转List*/
String[] userid = {"aa","bb","cc"};
List list = new ArrayList(Arrays.asList(userid));