我无法弄清楚如何将用户输入放在逗号分隔的列表中并将其放入ArrayList中

Question

I'm trying to present the user with text, then the user types a comma-separated list of full names (first and last) then hits enter, each full name is placed into an ArrayList, then the elements of the list are displayed back to the user.

So I tried this:

Scanner in = new Scanner(System.in);
ArrayList<String> members = new ArrayList<String>();
String[] groupName = new String[1];
System.out.print("Group Name: ");
groupName[0] = in.next().toLowerCase();
System.out.print("Names: ");
in.useDelimiter(",| ");
while (in.hasNext()){
    members.add(in.next().toLowerCase();
}
for (String m : members)
{
  System.out.println(m + ", ");
}

What happens is "Group Name: " displays, I type whatever I want the name to be then hit enter, then "Names: " displays, I enter "a aa, b bb, c cc" and hit enter, then nothing happens. What I expected to happen is the first element of the arraylist is set to "a aa", the second element to "b bb", and the third to "c cc" so it would print "a aa, b bb, c cc, " (I know this looks bad but it doesn't really matter, I'm just using this for now to make sure the ArrayList is being populated properly, which it's not). But the scanner seems to think there's still input so it gets stuck in the while loop. I've been trying a lot of different ways to fix this, some very convoluted using booleans in an attempt to break out of the while loop after hitting enter. I've been trying for hours and everything has failed. I'd really appreciate any help.

Answer 1

Your problem is that there is no way to stop your execution.

Could you just read the whole line of names using names = in.nextLine() and use String.split(",") to split the values?

Scanner in = new Scanner(System.in);
String[] groupName = new String[1];
System.out.print("Group Name: ");
groupName[0] = in.nextLine();
System.out.print("Names: ");
String names = in.nextLine();
String[] members = names.split(",");
System.out.println(Arrays.toString(members));
in.close();

Answer 2

There are two problems. First, use in.nextLine() instead of in.next().toLowerCase(). Then use split() function of taken input string and then divide the string in the array. Please try the following code.

    Scanner in = new Scanner(System.in);
    ArrayList<String> members = new ArrayList<String>();
    System.out.print("Group Name: ");
    String ab = in.nextLine();
    String[] splitString = ab.split(", ");
    for (String string : splitString)
    {
        //System.out.println("splited string: " + string);
        members.add(string);
    }
    System.out.println("Names: ");
    for (String m : members)
    { 
        System.out.println(m + ", ");
    }