学生成绩排序（比较器Comparator排序）

package com.liushuaishuai;

import java.util.Comparator;
import java.util.TreeSet;

public class TreeSetDemo {
    public static void main(String[] args) {
        TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>() {
            @Override
            public int compare(Student s1, Student s2) {
                int num = s2.getSum()-s1.getSum();
                int num2 = (num == 0 ? s1.getName().compareTo(s2.getName()):num);
                return num2;
            }
        });

        Student s1 = new Student("风清扬",95,98);
        Student s2 = new Student("流清扬",94,98);
        Student s3 = new Student("李清扬",93,98);
        Student s4 = new Student("B清扬",92,98);
        Student s5 = new Student("A清扬",92,98);


        ts.add(s1);ts.add(s2);ts.add(s3);ts.add(s4);ts.add(s5);

        for(Student s:ts) {
            System.out.println(s.getName()+","+s.getSum()+","+s.getChinese()+","+s.getMath());
        }
    }
}