用Java设计基于文件的学生成绩管理系统，包含添加，修改，查询，删除，保存学生信息的功能

您好！对于基于文件的学生成绩管理系统，您可以使用 Java 来设计并实现。下面是一个简单的实现示例，包含添加、修改、查询、删除和保存学生信息的功能：

import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class StudentManagementSystem {
    private static final String FILE_PATH = "students.txt";
    private static List<Student> students;

    public static void main(String[] args) {
        students = new ArrayList<>();
        loadStudents();

        Scanner scanner = new Scanner(System.in);
        int choice;
        do {
            System.out.println("学生成绩管理系统");
            System.out.println("1. 添加学生");
            System.out.println("2. 修改学生");
            System.out.println("3. 查询学生");
            System.out.println("4. 删除学生");
            System.out.println("5. 保存学生信息");
            System.out.println("0. 退出");

            System.out.print("请选择操作：");
            choice = scanner.nextInt();
            scanner.nextLine(); // 读取换行符

            switch (choice) {
                case 1:
                    addStudent(scanner);
                    break;
                case 2:
                    modifyStudent(scanner);
                    break;
                case 3:
                    queryStudent(scanner);
                    break;
                case 4:
                    deleteStudent(scanner);
                    break;
                case 5:
                    saveStudents();
                    break;
                case 0:
                    System.out.println("感谢使用！");
                    break;
                default:
                    System.out.println("无效的选择，请重新输入！");
                    break;
            }
        } while (choice != 0);
    }

    private static void addStudent(Scanner scanner) {
        System.out.print("请输入学生姓名：");
        String name = scanner.nextLine();
        System.out.print("请输入学生学号：");
        String id = scanner.nextLine();
        System.out.print("请输入学生成绩：");
        double score = scanner.nextDouble();
        scanner.nextLine(); // 读取换行符

        Student student = new Student(name, id, score);
        students.add(student);
        System.out.println("学生添加成功！");
    }

    private static void modifyStudent(Scanner scanner) {
        System.out.print("请输入要修改的学生学号：");
        String id = scanner.nextLine();
        boolean found = false;

        for (Student student : students) {
            if (student.getId().equals(id)) {
                System.out.print("请输入新的学生姓名：");
                String name = scanner.nextLine();
                System.out.print("请输入新的学生成绩：");
                double score = scanner.nextDouble();
                scanner.nextLine(); // 读取换行符

                student.setName(name);
                student.setScore(score);
                found = true;
                System.out.println("学生信息修改成功！");
                break;
            }
        }

        if (!found) {
            System.out.println("未找到该学生！");
        }
    }

    private static void queryStudent(Scanner scanner) {
        System.out.print("请输入要查询的学生学号：");
        String id = scanner.nextLine();
        boolean found = false;

        for (Student student : students) {
            if (student.getId().equals(id)) {
                System.out.println("学生姓名：" + student.getName());
                System.out.println("学生成绩：" + student.getScore());
                found = true;
                break;
            }
        }

        if (!found) {
            System.out.println("未找到该学生！");
        }
    }

    private static void deleteStudent(Scanner scanner) {
        System.out.print("请输入要删除的学生学号：");
        String id = scanner.nextLine();
        boolean removed = false;

        for (Student student : students) {
            if (student.getId().equals(id)) {
                students.remove(student);
                removed = true;
                System.out.println("学生删除成功！");
                break;
            }
        }

        if (!removed) {
            System.out.println("未找到该学生！");
        }
    }

    private static void saveStudents() {
        try (PrintWriter writer = new PrintWriter(FILE_PATH)) {
            for (Student student : students) {
                writer.println(student.getName() + "," + student.getId() + "," + student.getScore());
            }
            System.out.println("学生信息保存成功！");
        } catch (IOException e) {
            System.out.println("保存学生信息失败：" + e.getMessage());
        }
    }

    private static void loadStudents() {
        File file = new File(FILE_PATH);
        if (!file.exists()) {
            return;
        }

        try (Scanner scanner = new Scanner(file)) {
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                String[] parts = line.split(",");
                if (parts.length == 3) {
                    String name = parts[0];
                    String id = parts[1];
                    double score = Double.parseDouble(parts[2]);
                    Student student = new Student(name, id, score);
                    students.add(student);
                }
            }
            System.out.println("学生信息加载成功！");
        } catch (IOException e) {
            System.out.println("加载学生信息失败：" + e.getMessage());
        }
    }

    static class Student {
        private String name;
        private String id;
        private double score;

        public Student(String name, String id, double score) {
            this.name = name;
            this.id = id;
            this.score = score;
        }

        // getter 和 setter 方法省略

        public String getName() {
            return name;
        }

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

        public String getId() {
            return id;
        }

        public void setId(String id) {
            this.id = id;
        }

        public double getScore() {
            return score;
        }

        public void setScore(double score) {
            this.score = score;
        }
    }
}

该示例使用一个 `Student` 类来表示学生对象，包含姓名、学号和成绩等属性。学生信息保存在一个 `List` 集合中，在程序运行时从文件中加载，并在退出前保存到文件中。

注意：该示例只是一个简单的实现，没有进行输入验证和异常处理。在实际应用中，您可能需要添加额外的功能和改进代码以满足实际需求。