集合IO流

package com.shujia.day17.ketang;



/*
        键盘录入5个学生信息(姓名,语文成绩,数学成绩,英语成绩),按照总分从高到低存入文本文件

 */

import java.io.BufferedReader;
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 IOTest3 {
    public static void main(String[] args) throws IOException {
        //创建键盘录入对象
        Scanner sc = new Scanner(System.in);
        //创建TreeSet集合对象
        TreeSet<Student> set = new TreeSet<>(new Comparator<Student>() {
            @Override
            public int compare(Student o1, Student o2) {
                //主要条件：总分从高到低
                int i = o2.getSumScore() - o1.getSumScore();
                //隐含条件
                //总成绩一样，语文成绩不一定一样
                int i2 = (i == 0) ? o2.getChinese() - o1.getChinese() : i;
                //语文成绩一样，数学成绩不一定一样
                int i3 = (i2 == 0) ? o2.getMath() - o1.getMath() : i2;

                //姓名不一定一样
                int i4 = (i3 == 0) ? o2.getName().compareTo(o1.getName()) : i3;
                return i4;
            }
        });

        Student student = null;
        for (int i = 1; i <= 5; i++) {
            System.out.println("请输入第" + i + "个学生的信息：");
            System.out.println("请输入姓名：");
            String name = sc.next();
            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 = new Student(name, chinese, math, english);
            set.add(student);
            System.out.println("---------------------------------------------");
        }
        StringBuffer sb = null;
        //创建字符缓冲输入流对象
        BufferedWriter bw = new BufferedWriter(new FileWriter("studentInfo.txt"));

        //遍历集合得到每个学生信息，将学生信息组成字符串写入到文件中
        for(Student student1 : set){
            sb = new StringBuffer();
            String name = student1.getName();
            int chinese = student1.getChinese();
            int math = student1.getMath();
            int english = student1.getEnglish();
            int sumScore = student1.getSumScore();
            sb.append("姓名：")
                    .append(name)
                    .append("，语文成绩：")
                    .append(chinese)
                    .append("，数学成绩：")
                    .append(math)
                    .append("，英语成绩：")
                    .append(english)
                    .append("，总成绩：")
                    .append(sumScore);
            //将StringBuffer转成字符串
            String s = sb.toString();
            bw.write(s);
            bw.newLine();
            bw.flush();
        }

        System.out.println("所有学生信息录入存储完毕！");


        //释放资源
        bw.close();


    }
}

student类

package com.shujia.day17.ketang;



public class Student {
    private String name;
    private int chinese;
    private int math;
    private int english;

    public Student() {
    }

    public Student(String name, int chinese, int math, int english) {
        this.name = name;
        this.chinese = chinese;
        this.math = math;
        this.english = english;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getChinese() {
        return chinese;
    }

    public void setChinese(int chinese) {
        this.chinese = chinese;
    }

    public int getMath() {
        return math;
    }

    public void setMath(int math) {
        this.math = math;
    }

    public int getEnglish() {
        return english;
    }

    public void setEnglish(int english) {
        this.english = english;
    }

    public int getSumScore() {
        return chinese + math + english;
    }

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