Java中Arraylists的排列和组合？

Question

我有三个像这样的Arraylists

List<String> list1 = new ArrayList<String>();    
List<String> list2 = new ArrayList<String>();    
List<String> finallist = new ArrayList<String>();   

list1包含项目"a","b"list2包含项目1,2,3如何制作一个包含"a1""a2""a3""b1""b2""b3"的finallist

Answer 1

假设列表看起来像这样:

    List<String> list1 = Arrays.asList("a", "b", "c");
    List<String> list2 = Arrays.asList("1", "2", "3");

然后:

    List<String> finalList = new ArrayList<String>();
    for (String letter: list1) {
        for (String number: list2) {
            finalList.add(letter + number);
        }
    }

    System.out.println(finalList);