Java stream groupingBy key 作为最大工资员工和价值作为部门的所有员工

Question

我有一个清单 Employee

public class Employee {
  private String name;
  private Integer age;
  private Double salary;
  private Department department;
}

List<Employee> employeeList = Arrays.asList(
      new Employee("Tom Jones", 45, 12000.00,Department.MARKETING),
      new Employee("Harry Major", 26, 20000.00, Department.LEGAL),
      new Employee("Ethan Hardy", 65, 30000.00, Department.LEGAL),
      new Employee("Nancy Smith", 22, 15000.00, Department.MARKETING),
      new Employee("Catherine Jones", 21, 18000.00, Department.HR),
      new Employee("James Elliot", 58, 24000.00, Department.OPERATIONS),
      new Employee("Frank Anthony", 55, 32000.00, Department.MARKETING),
      new Employee("Michael Reeves", 40, 45000.00, Department.OPERATIONS));

我想知道Map<Employee, List<Employee>>每个部门的最高工资员工的映射键在哪里，值是该部门的所有员工。我正在尝试 groupingBy 但它为所有员工提供了部门地图。如何将所有最高工资员工作为映射键？

Map<Department,List<Employee>> employeeMap
        = employeeList.stream().collect(Collectors.groupingBy(Employee::getDepartment));