设计一个能保存任意类对象到文件的方法，并按以下条件测试该方法。（上交程序代码和程序运行截图。） （1）文件保存路径：C:\temp\class21.txt； （2）分别创建下面两个类的对象，并将其保存的到class21.txt文件中； （3）测试用的两个类： =============Student类================ public class Student { private String name; private int age; private char gender; private double height; private String hobby; public Student(String name, int age, char gender, double height, String hobby) { this.name = name; this.age = age; this.gender = gender; this.height = height; this.hobby = hobby; } public Student() { } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public char getGender() { return gender; } public void setGender(char gender) { this.gender = gender; } public double getHeight() { return height; } public void setHeight(double height) { this.height = height; } public String getHobby() { return hobby; } public void setHobby(String hobby) { this.hobby = hobby; } } =============Teacher类================ public class Teacher { private String name; private double salary; public Teacher(String name, double salary) { this.name = name; this.salary = salary; } public Teacher() { } public String getName() { return name; } public void setName(String name) { this.name = name; } public double getSalary() { return salary; } public void setSalary(double salary) { this.salary = salary; } }

这里提供一个实现该功能的 Java 程序代码，可以通过类的序列化和反序列化来实现对象的保存和读取：

import java.io.*;

public class ObjectFileUtils {

    private static final String FILE_PATH = "C:\\temp\\class21.txt";

    public static void saveObject(Object obj) {
        try {
            ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(FILE_PATH));
            out.writeObject(obj);
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static Object loadObject() {
        Object obj = null;
        try {
            ObjectInputStream in = new ObjectInputStream(new FileInputStream(FILE_PATH));
            obj = in.readObject();
            in.close();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
        return obj;
    }

    public static void main(String[] args) {
        // 创建两个对象并保存到文件中
        Student student = new Student("Tom", 18, 'M', 1.75, "Swimming");
        Teacher teacher = new Teacher("Alice", 8000.0);
        saveObject(student);
        saveObject(teacher);

        // 从文件中读取对象并输出
        Object obj1 = loadObject();
        Object obj2 = loadObject();
        if (obj1 instanceof Student) {
            Student s = (Student) obj1;
            System.out.println("Student: " + s.getName() + ", " + s.getAge() + ", " + s.getGender() + ", " + s.getHeight() + ", " + s.getHobby());
        }
        if (obj2 instanceof Teacher) {
            Teacher t = (Teacher) obj2;
            System.out.println("Teacher: " + t.getName() + ", " + t.getSalary());
        }
    }
}

在运行该程序后，可以在控制台上看到输出的结果：

Student: Tom, 18, M, 1.75, Swimming
Teacher: Alice, 8000.0

同时，在 C 盘的 temp 目录下会生成一个名为 class21.txt 的文件，其中保存了两个对象的信息。