Stream List、Set、Map 初始化

原创转载请注明出处：https://www.cnblogs.com/agilestyle/p/12812686.html

List

@Test
public void listInitTest() {
    List<Integer> list = Stream.of(1, 2, 3, 4, 5, 6).collect(Collectors.toList());

    // [1, 2, 3, 4, 5, 6]
    System.out.println(list);
}

Set

@Test
public void setInitTest() {
    Set<Integer> set = Stream.of(1, 1, 2, 2, 3, 3).collect(Collectors.toSet());

    // [1, 2, 3]
    System.out.println(set);
}

Map

@Test
public void mapInitTest() {
    Map<Integer, String> map = Stream.of(new Object[][]{
            {1, "hello"},
            {2, "world"},
    }).collect(Collectors.toMap(data -> (Integer) data[0], data -> (String) data[1]));

    // {1=hello, 2=world}
    System.out.println(map);
}

Reference

https://www.baeldung.com/java-init-list-one-line

https://www.baeldung.com/java-initialize-hashmap

https://www.baeldung.com/java-8-collectors