Java 8 – Convert Map to List
Introduction#
Convert Map to List in java 8 using stream api
Java 8 – Convert Map to List
public class ConvertMapToList {
public static void main(String[] args) {
Map<Integer, String> map = new HashMap<>();
map.put(10, "apple");
map.put(20, "orange");
map.put(30, "banana");
map.put(40, "watermelon");
map.put(50, "dragonfruit");
System.out.println("\n1. Export Map Key as List of Integrer method 1");
List<Integer> methodOneIntegers= map.entrySet().stream()
.map(x -> x.getKey())
.collect(Collectors.toList());
methodOneIntegers.forEach(System.out::println);
System.out.println("\n1. Export Map Key as List of Integrer method 2");
List<Integer> methodTwoIntegers= map.keySet().stream()
.collect(Collectors.toList());
methodOneIntegers.forEach(System.out::println);
System.out.println("\n2. Export Map Value as List of String method 1");
List<String> methodOneStrings= map.entrySet().stream()
.map(x -> x.getValue())
.collect(Collectors.toList());
methodOneStrings.forEach(System.out::println);
System.out.println("\n2. Export Map Value as List of String method 2");
List<String> methodTwoStrings= map.values().stream()
.map(x -> x.getValue())
.collect(Collectors.toList());
methodTwoStrings.forEach(System.out::println);
}
}
Output
Export Map Key as List of Integrer method 1
50
20
40
10
30
Export Map Key as List of Integrer method 2
50
20
40
10
30
Export Map Value as List of String method 1
dragonfruit
orange
watermelon
apple
banana
Export Map Value as List of String method 2
dragonfruit
orange
watermelon
apple
banana