[Java] Array <-> ArrayList 변환

1. List -> Array

1) for문

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

arrlist.add("string1");
arrlist.add("string2");
arrlist.add("string3");

String[] arr = new String[arrlist.size()];
for(int i = 0; i < arr.length; i++) {
	arr[i] = arrlist.get(i);
}

2) toArray() 메서드 사용

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

arrlist.add("string1");
arrlist.add("string2");
arrlist.add("string3");

String[] arr = arrlist.toArray(new String[arrlist.size()]);

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2. Array -> List

1) for문

String[] arr = new String[3];
arr[0] = "string1";
arr[1] = "string2";
arr[2] = "string3";

ArrayList<String> arrlist = new ArrayList<>();
for(String s : arr) {
	arrlist.add(s);
}

2) Arrays.asList() 사용

String[] arr = new String[3];
arr[0] = "string1";
arr[1] = "string2";
arr[2] = "string3";

ArrayList<String> arrlist = new ArrayList<>(Arrays.asList(arr));