如果父类实现并重写了compareTo方法，那么其子类同样具有该方法，可以直接加入TreeSet

class Person implements Comparable<Person> {
   String name;
   public Person(String name) {
      this.name = name;
   }
   @Override
   public int compareTo(Person o) {
      return (this.name.compareTo(o.name) == 0) ? this.getClass().getName().compareTo(o.getClass().getName()) : this.name.compareTo(o.name);
   }
}
class Teacher extends Person {
   @Override
   public String toString() {
      return this.getClass().getName()+":姓名：" + super.name + ",职称：" + title;
   }
   String title;
   public Teacher(String name, String title) {
      super(name);
      this.title = title;
   }
class Worker extends Person {
   String job;
   public Worker(String name,String job) {
      super(name);
      this.job=job;
   }
   @Override
   public String toString() {
      return this.getClass().getName()+":姓名:"+name+",工种:"+job;
   }
}