集合到文件（数据排序改进版）

package com.io.liushuaishuai;

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 ArrayListToTxDemo01 {
    public static void main(String[] args) throws IOException {
        TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>() {
            @Override
            public int compare(Student s1, Student s2) {
                int num = s2.sum() - s1.sum();
                int num2 = num == 0 ? s2.getChinese() - s1.getChinese() : num;
                int num3 = num2 == 0 ? s2.getMath() - s1.getMath() : num2;
                int num4 = num3 == 0 ? s2.getName().compareTo(s1.getName()) : num3;
                return num4;

            }
        });

        int i;
        for (i = 0; i < 5; i++) {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入第" + (i + 1) + "个学生的信息");
            System.out.println("请输入姓名");
            String name = sc.nextLine();
            System.out.println("请输入语文成绩");
            int chinese = sc.nextInt();
            System.out.println("请输入数学成绩");
            int math = sc.nextInt();
            System.out.println("请输入英语成绩");
            int english = sc.nextInt();
            Student s = new Student(name, chinese, math, english);
            ts.add(s);
        }
        BufferedWriter bw = new BufferedWriter(new FileWriter("myIOstream\fos.txt"));
        for (Student s : ts) {
            StringBuilder sb = new StringBuilder();
            StringBuilder str = sb.append(s.getName()).append(",").append(s.getChinese()).append(",").append(s.getMath()).append(",").append(s.getEnglish()).append(",").append(s.sum());
            String s1 = str.toString();
            bw.write(s1);
            bw.newLine();
            bw.flush();
        }

        bw.close();


    }
}