JAVA_集合到文件数据排序

案例

*需求:键盘录入5个学生信息(姓名,语文成绩,数学成绩英语成绩)。要求按照成绩总分从高到低写入文本文件
格式:姓名,语文成绩,数学成绩英语成绩 举例:林青霞98,99,100

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Comparator;
import java.util.Scanner;
import java.util.TreeSet;

public class Demo05Scanner {
    public static void main(String[] args) throws IOException {

        TreeSet<Student> ts = new TreeSet<>(new Comparator<Student>() {
            @Override
            public int compare(Student st1, Student st2) {
                //成绩从高到底
                int num = st2.getSum() - st1.getSum();
                //次要条件
                //语文成绩相同
                int num2 = num ==0? st1.getChinese() -st2.getChinese() : num;
                //数学成绩相同
                int num3 = num2 ==0 ? st1.getMath() - st2.getMath() : num2;
                int num4 = num3 == 0 ? st1.getName().compareTo(st2.getName()) : num3;
                return num4;
            }
        });

        BufferedWriter bw = new BufferedWriter(new FileWriter("D:\\java\\成绩.txt"));

        Scanner sc = new Scanner(System.in);

        for (int i = 0; i < 5; i++) {
            Student stu = new Student();
            System.out.println("请第"+(i + 1)+"次输入姓名：");
            String name = sc.next();
            stu.setName(name);
            System.out.println("请"+(i + 1)+"次输入语文成绩：");
            int chinese = sc.nextInt();
            stu.setChinese(chinese);
            System.out.println("请"+(i + 1)+"次输入数学成绩：");
            int match = sc.nextInt();
            stu.setMath(match);
            System.out.println("请"+(i + 1)+"次输入英语成绩：");
            int english = sc.nextInt();
            stu.setEnglish(english);

            ts.add(stu);

        }

        for (Student t : ts) {
            //格式：姓名，语文成绩，数学成绩，英语成绩
            StringBuilder sb = new StringBuilder();
            sb.append(t.getName()).append(",").append(t.getChinese()).append(",").append(t.getMath()).append(",").append(t.getEnglish());

            bw.write(sb.toString());
            bw.newLine();
            bw.flush();
        }
            bw.close(); // 释放资源
    }