使用对象流写入和读取文件中的对象

首先，需要创建一个类，该类需要实现Serializable接口，以便对象可以序列化和反序列化。例如，我们创建一个Person类：

import java.io.Serializable;

public class Person implements Serializable {
    private String name;
    private int age;
    private String address;

    public Person(String name, int age, String address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getAddress() {
        return address;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                '}';
    }
}

然后，我们可以使用对象输出流将一个Person对象写入文件中：

import java.io.*;

public class Main {
    public static void main(String[] args) {
        try {
            FileOutputStream fos = new FileOutputStream("person.txt");
            ObjectOutputStream oos = new ObjectOutputStream(fos);

            Person person = new Person("Alice", 25, "123 Main St");
            oos.writeObject(person);

            oos.close();
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

最后，我们可以使用对象输入流从文件中读取对象：

import java.io.*;

public class Main {
    public static void main(String[] args) {
        try {
            FileInputStream fis = new FileInputStream("person.txt");
            ObjectInputStream ois = new ObjectInputStream(fis);

            Person person = (Person) ois.readObject();
            System.out.println(person);

            ois.close();
            fis.close();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

输出结果为：

Person{name='Alice', age=25, address='123 Main St'}