How can I convert a String array to a different Class ArrayList in Java

Question

I'm trying to figure out how to write logic to convert an array of string into an ArrayList weekday object

String[] weekdays = request.getParameterValues("weekday");

I've made my ArrayList weekday2 the length of my String[] weekdays.

ArrayList<WeekDay> weekdays2 = new ArrayList<WeekDay>(weekdays.length);

I know there is a way to utilize enums, and that's what I'm trying to do.

for (int i = 0; i < weekdays.length; i++) {
            weekdays2.add(new WeekDay().valueOf(weekdays2, weekdays));
        }

I know I'm definitely missing something.

error:

The method valueOf(Class<T>, String) in the type Enum<WeekDay> is not applicable for the arguments (ArrayList<WeekDay>, String[])

@alexander - It just has an enum in it. The array and arraylist above are in one of my servlets. My WeekDay enum is just this currently. — Evan Chapman
– Evan Chapman, Commented Sep 3, 2020 at 14:50
@alexander public enum WeekDay { MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY } — Evan Chapman
– Evan Chapman, Commented Sep 3, 2020 at 14:50

Alexandr Ivanov · Accepted Answer · 2020-09-03 15:09:12Z

1

Code to get list of WeekDay may be such:

    for (int i = 0; i < weekdays.length; i++) {
        weekdays2.add(WeekDay.valueOf(weekdays[i]));
    }

answered Sep 3, 2020 at 15:09

Alexandr Ivanov

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3 Comments

I would suggest to add toUpperCase() since valueOf() matches for the exact identifier.

I think when you develop web application you control all possible parameter values.

Yeah you're right, however this would make the code a little safer at low cost.