Java自定义类toString()方法：优化对象打印输出

import java.util.Arrays;

public class Main {
    private static class Student {
        String fName;
        String lName;
        int id;
        int score;

        public Student(String fName, String lName, int id, int score) {
            this.fName = fName;
            this.lName = lName;
            this.id = id;
            this.score = score;
        }
        // ... 其他方法（如getScore()）
    }

    public static void main(String[] args) {
        Student s1 = new Student("Mo", "Nee", 1, 900);
        Student s2 = new Student("Lee", "Jen", 2, 600);
        Student[] students = {s1, s2};
        System.out.println(Arrays.toString(students));
        // 预期输出可能类似：[Main$Student@hashcode1, Main$Student@hashcode2]
    }
}

public String toString() {
    return getClass().getName() + "@" + Integer.toHexString(hashCode());
}

import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
    private static class Student {
        String fName; // First Name
        String lName; // Last Name
        int id; // Student ID
        int score; // Score

        public Student(String fName, String lName, int id, int score) {
            this.fName = fName;
            this.lName = lName;
            this.id = id;
            this.score = score;
        }

        public int getScore() {
            return score;
        }

        /**
         * 重写toString方法，提供Student对象的有意义字符串表示
         */
        @Override
        public String toString() {
            return "id: " + this.id + ", fName: " + this.fName + ", lName: " + this.lName + ", score: " + this.score;
        }
    }

    // 辅助方法：检查字符串是否只包含字母
    public static boolean alphabetic(String str) {
        char[] charArray = str.toCharArray();
        for (char c : charArray) {
            if (!Character.isLetter(c))
                return false;
        }
        return true;
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入学生数量:");
        int k = input.nextInt(); // 学生数量
        Student[] students = new Student[k];

        for (int i = 0; i < k; ) {
            System.out.println("请输入学生ID:");
            int id = input.nextInt();
            System.out.println("请输入学生姓氏:");
            String fName = input.next();
            while (!alphabetic(fName)) {
                System.out.println("输入错误！姓氏必须只包含字母，请重新输入:");
                fName = input.next();
            }
            System.out.println("请输入学生名字:");
            String lName = input.next();
            while (!alphabetic(lName)) {
                System.out.println("输入错误！名字必须只包含字母，请重新输入:");
                lName = input.next();
            }
            System.out.println("请输入学生分数:");
            int score = input.nextInt();

            students[i++] = new Student(fName, lName, id, score);
        }

        // 使用Comparator按分数降序排序
        class ByScoreComparator implements Comparator<Student> {
            @Override
            public int compare(Student s1, Student s2) {
                // 对于降序排序，比较s2和s1的分数
                return Integer.compare(s2.getScore(), s1.getScore());
            }
        }
        Arrays.sort(students, new ByScoreComparator());

        System.out.println("\n排序后的学生信息:");
        System.out.println(Arrays.toString(students)); // 现在会打印有意义的内容

        input.close();
    }
}

请输入学生数量:
2
请输入学生ID:
1
请输入学生姓氏:
Mo
请输入学生名字:
Nee
请输入学生分数:
900
请输入学生ID:
2
请输入学生姓氏:
Lee
请输入学生名字:
Jen
请输入学生分数:
600

排序后的学生信息:
[id: 1, fName: Mo, lName: Nee, score: 900, id: 2, fName: Lee, lName: Jen, score: 600]