如何将Map转为List?分为2种情况,一种是将Map中的key转为List,一种是将Map中的value转为List
import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class Main2Test { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(1, "1a"); map.put(2, "2b"); map.put(3, "3c"); map.put(3, "3d"); map.put(4, "4a"); List<Integer> keyList = new ArrayList(map.keySet()); for (Integer tmp : keyList) { System.out.println(tmp); } List<String> valueList = new ArrayList<>(map.values()); for (String tmp : valueList) { System.out.println(tmp); } } } 复制代码