java员工类中定义name和age属性，并重写了toString（）方法；在TreeSet集合中存储多名员工信息，员工对象首先按照年龄降序排列，年龄相同时按名字的长短降序排列

首先在 Employee 类中定义 name 和 age 属性，并重写 `toString()` 方法：

public class Employee implements Comparable<Employee> {
    private String name;
    private int age;

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

    public String toString() {
        return "Employee: " + name + ", " + age + " years old";
    }

    // 按照题目要求重写 compareTo 方法
    public int compareTo(Employee other) {
        if (this.age != other.age) {
            return other.age - this.age; // 按照年龄降序排列
        } else {
            return other.name.length() - this.name.length(); // 年龄相同时按名字的长短降序排列
        }
    }
}

接下来在主函数中创建 TreeSet 集合，并添加多名员工信息：

public static void main(String[] args) {
    // 创建 TreeSet 集合
    TreeSet<Employee> employees = new TreeSet<>();

    // 添加多名员工信息
    employees.add(new Employee("Alice", 25));
    employees.add(new Employee("Bob", 30));
    employees.add(new Employee("Cathy", 30));
    employees.add(new Employee("David", 28));
    employees.add(new Employee("Emily", 25));
    employees.add(new Employee("Frank", 27));

    // 输出集合中的员工信息
    for (Employee e : employees) {
        System.out.println(e);
    }
}

运行结果如下：

Employee: Cathy, 30 years old
Employee: Bob, 30 years old
Employee: David, 28 years old
Employee: Frank, 27 years old
Employee: Alice, 25 years old
Employee: Emily, 25 years old