java中List、Array、Map、Set等集合相互转换
java中List、Array、Map、Set等集合相互转换
在java中,我们经常需要对List、Array等做一些转换操作,当然转换方法有很多种,但哪种方法既方便又高效呢?在这里向大家介绍一下集合间的最佳转换方法。
1.List转换为Array
Listlist=newArrayList (); list.add("China"); list.add("Switzerland"); list.add("Italy"); list.add("France"); String[]countries=list.toArray(newString[list.size()]);
2.Array转换为List
String[]countries={"China","Switzerland","Italy","France"}; Listlist=Arrays.asList(countries);
3.Map转换为List
Listlist=newArrayList (map.values());
4.Array转换为Set
String[]countries={"India","Switzerland","Italy"}; Setset=newHashSet (Arrays.asList(countries)); System.out.println(set);
5.Map转换为Set
MapsourceMap=createMap(); Set targetSet=newHashSet<>(sourceMap.values());
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