在java中,我們經常需要對List、Array等做一些轉換操作,當然轉換方法有很多種,但哪種方法既方便又高效呢?在這裏向大家介紹一下集合間的最佳轉換方法。
1.List轉換爲Array:
List<String> list = new ArrayList<String>();
list.add("China");
list.add("Switzerland");
list.add("Italy");
list.add("France");
String [] countries = list.toArray(new String[list.size()]);
2.Array轉換爲List:
String[] countries = {"China", "Switzerland", "Italy", "France"};
List list = Arrays.asList(countries);
3.Map轉換爲List:
List<Value> list = new ArrayList<Value>(map.values());
4.Array轉換爲Set
String [] countries = {"India", "Switzerland", "Italy"};
Set<String> set = new HashSet<String>(Arrays.asList(countries));
System.out.println(set);
5.Map轉換爲Set
Map<Integer, String> sourceMap = createMap();
Set<String> targetSet = new HashSet<>(sourceMap.values());