在Java中实现List： 员工管理系统 员工属性：员工编号、员工姓名、性别、年龄、所在部门 1—员工添加 员工信息修改 4—根据员工编号查询员工信息 5—查询所有员工信息要求1.员工信息存储在TreeSet中2.按照员工编号进行升序排序

好的，这是一个很实用的问题，下面是一个简单的Java代码示例，可以实现这个员工管理系统：

import java.util.*;

public class EmployeeManagementSystem {
    private TreeSet<Employee> employees;

    public EmployeeManagementSystem() {
        employees = new TreeSet<>(Comparator.comparingInt(Employee::getId));
    }

    public void addEmployee(Employee employee) {
        employees.add(employee);
    }

    public void modifyEmployee(Employee employee) {
        employees.remove(employee);
        employees.add(employee);
    }

    public Employee getEmployeeById(int id) {
        for (Employee employee : employees) {
            if (employee.getId() == id) {
                return employee;
            }
        }
        return null;
    }

    public List<Employee> getAllEmployees() {
        return new ArrayList<>(employees);
    }
}

class Employee {
    private int id;
    private String name;
    private String gender;
    private int age;
    private String department;

    public Employee(int id, String name, String gender, int age, String department) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.department = department;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                ", department='" + department + '\'' +
                '}';
    }
}

这个代码示例中，我们首先定义了一个员工类 `Employee`，它包含了员工的属性。然后我们定义了一个员工管理系统 `EmployeeManagementSystem`，它包含了添加员工、修改员工、根据员工编号查询员工信息、查询所有员工信息等方法。注意，我们使用了 `TreeSet` 来存储员工信息，并且在构造函数中指定了按照员工编号进行升序排序的比较器。最后，我们在 `main` 函数中演示了如何使用这个员工管理系统。