JavaSE-19.1.1【IO流练习案例-集合到文件（排序改进版）】

package day10.lesson1.p1;

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

/*
1 IO流练习

1.1 案例-集合到文件（排序改进版）

    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

    定义学生类
    2. 创建TreeSet集合，通过比较器排序进行排序
    3. 键盘录入学生数据
    4. 创建学生对象，把键盘录入的数据对应赋值给学生对象的成员变量
    5. 把学生对象添加到TreeSet集合
    6. 创建字符缓冲输出流对象
    7. 遍历集合，得到每一个学生对象
    8. 把学生对象的数据拼接成指定格式的字符串
    9. 调用字符缓冲输出流对象的方法写数据
    10. 释放资源
 */
public class TreeSetToFileDemo {
    public static void main(String[] args) throws IOException {
        TreeSet<Student> treeSet = new TreeSet<>(new Comparator<Student>() { //比较器排序
            @Override
            public int compare(Student s1, Student s2) { //自定义比较规则
                //主要条件
                int num = s2.getSum() - s1.getSum();
                //次要条件
                int num2 = (num==0) ? (s1.getChinese()-s2.getChinese()) : num;
                int num3 = (num2==0) ? (s1.getMath()-s2.getMath()) : num2;
                int num4 = (num3==0) ? (s1.getName().compareTo(s2.getName())) : num3;
                return num4;
            }
        });

        for (int i=1; i<=5; i++){
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入第" + i + "个学生的信息：");
            System.out.println("姓名：");
            String name = sc.nextLine();
            System.out.println("语文成绩:");
            int chinese = sc.nextInt();
            System.out.println("数学成绩：");
            int math = sc.nextInt();
            System.out.println("英语成绩：");
            int english = sc.nextInt();

            Student student = new Student();
            student.setName(name);
            student.setChinese(chinese);
            student.setMath(math);
            student.setEnglish(english);

            treeSet.add(student);
        }

        BufferedWriter bw = new BufferedWriter(new FileWriter("stage2\\src\\day10\\lesson1\\ts.txt"));

        for (Student s: treeSet){
            StringBuilder sb = new StringBuilder();
            sb.append(s.getName()).append(",").append(s.getChinese()).append(",").append(s.getMath()).append(",").append(s.getEnglish()).append(",").append(s.getSum());

            bw.write(sb.toString());
            bw.newLine();
            bw.flush();
        }

        bw.close();
    }
}

package day10.lesson1.p1;

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

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

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

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

    public String getName() {
        return name;
    }

    public int getChinese() {
        return chinese;
    }

    public int getMath() {
        return math;
    }

    public int getEnglish() {
        return english;
    }

    public int getSum(){
        return this.chinese + this.math + this.english;
    }
}

 

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1 2 3 4 5

冯七,85,85,75,245 王五,55,99,88,242 张三,90,80,70,240 赵六,88,77,66,231 李四,80,60,80,220