java中如何实现数组、List、Set、Map之间互相转换。

1、数组转List:

String[] countries = {"Array", "List", "Set", "Map"};

List list = Arrays.asList(countries);

2、Array转:Set

String [] countries = {"Array", "List", "Set"};

Set<String> set = new HashSet<String>(Arrays.asList(countries));

System.out.println(set);

3、List转Array:

List<String> list = new ArrayList<String>();

list.add("Array");

list.add("List");

list.add("Set");

list.add("Map");

String [] countries = list.toArray(new String[list.size()]);

4、Map转List:

List<Value> list = new ArrayList<Value>(map.values());

5、Map转Set:

Map<Integer, String> map = createMap();

Set<String> set = new HashSet<>(map.values());

6、List转Set:

String[] staffs = new String[]{"Array", "List", "Set"};

List staffsList = Arrays.asList(staffs);

Set result = new HashSet(staffsList);