Array转List

String[] s = new String[]{"A", "B", "C", "D","E"};
List<String> list = Arrays.asList(s);

值得注意的是上边转换过来的List并不是java.util.ArrayList，而是java.util.Arrays#ArrayList，这个使用的时候要注意下。

List转Array

String[] dest = list.toArray(new String[0]);//new String[0]是指定返回数组的类型
System.out.println("dest: " + Arrays.toString(dest));

List转Set

Set<String> set = new HashSet<>(list);

Set转List

List<String> list_1 = new ArrayList<>(set);

Array转Set

s = new String[]{"A", "B", "C", "D","E"};
set = new HashSet<>(Arrays.asList(s));

Set转Array

dest = set.toArray(new String[0]);