2、定义一个TreeSet集合用来存储学生对象（要求按照姓名排序显示）

可以使用以下代码来定义一个TreeSet集合用来存储学生对象，并按照姓名排序显示：

import java.util.TreeSet;

public class Test {
    public static void main(String[] args) {
        TreeSet<Student> set = new TreeSet<>();
        set.add(new Student("Tom", 19));
        set.add(new Student("Jerry", 18));
        set.add(new Student("Alice", 20));
        set.add(new Student("Bob", 22));
        for (Student student : set) {
            System.out.println(student);
        }
    }
}

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

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

    @Override
    public int compareTo(Student o) {
        return this.name.compareTo(o.name);
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

输出结果为：

Student{name='Alice', age=20}
Student{name='Bob', age=22}
Student{name='Jerry', age=18}
Student{name='Tom', age=19}