Java通過stream將list轉換成map

List<Employee> department = new LinkedList<>(
        Arrays.asList(
                new Employee("張三", 12, "2012-11-12"),
                new Employee("李四", 9, "2018-06-01"),
                new Employee("王五", 11.5, "2019-06-01"),
                new Employee("趙六", 11.2, "2018-11-02")
        )
);


Map<Integer, Employee> map = department.stream().collect(Collectors.toMap(Employee::getId, (employee -> employee)));
map.forEach((id, employee)->{
    System.out.println(id+", "+employee.getName());
});