java ArrayList set等转化
数组和ArrayList转化
String[] arr = new String[]{"1","2"};
List strings = Arrays.asList(arr);
String[] strings1 = strings.toArray(new String[0]);
list 和set 转化
String[] arr = new String[]{"1","2"};
List strings = Arrays.asList(arr);
Set set = new HashSet<>(strings);
List strings1 = new ArrayList<>(set);
list 和map转化
String[] arr = new String[]{"1","2"};
List strings = Arrays.asList(arr);
Set set = new HashSet<>(strings);
List strings1 = new ArrayList<>(set);
Map collect = strings1.stream().collect(Collectors.toMap(item -> item, item -> item));
