Java中为什么要实现Serializable序列化

import java.io.*;
public class SerializationDemo {
    public static void main(String[] args) {
        // 创建一个对象
        Employee employee = new Employee("John", "Doe", 30, "123-456-7890");
        // 将对象序列化到文件
        try (FileOutputStream fos = new FileOutputStream("employee.ser");
             ObjectOutputStream oos = new ObjectOutputStream(fos)) {
            oos.writeObject(employee);
            System.out.println("Employee object serialized.");
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 从文件中反序列化对象
        try (FileInputStream fis = new FileInputStream("employee.ser");
             ObjectInputStream ois = new ObjectInputStream(fis)) {
            Employee deserializedEmployee = (Employee) ois.readObject();
            System.out.println("Employee object deserialized: " + deserializedEmployee);
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

import java.io.*;
import java.net.*;
public class NetworkSerializationDemo {
    public static void main(String[] args) {
        try {
            // 创建Socket连接
            ServerSocket serverSocket = new ServerSocket(8080);
            Socket clientSocket = serverSocket.accept();
            // 创建对象并序列化发送
            Employee employee = new Employee("Alice", "Smith", 25, "987-654-3210");
            ObjectOutputStream out = new ObjectOutputStream(clientSocket.getOutputStream());
            out.writeObject(employee);
            // 关闭连接
            out.close();
            clientSocket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import java.io.*;
import java.sql.*;
public class DatabaseSerializationDemo {
    public static void main(String[] args) {
        try {
            // 连接到数据库
            Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "user", "password");
            // 创建对象并序列化
            Employee employee = new Employee("Bob", "Johnson", 28, "456-789-0123");
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
            objectOutputStream.writeObject(employee);
            // 将对象字节流存储到数据库
            PreparedStatement preparedStatement = connection.prepareStatement("INSERT INTO employees (data) VALUES (?)");
            preparedStatement.setBytes(1, byteArrayOutputStream.toByteArray());
            preparedStatement.executeUpdate();
            // 关闭连接
            objectOutputStream.close();
            byteArrayOutputStream.close();
            preparedStatement.close();
            connection.close();
        } catch (SQLException | IOException e) {
            e.printStackTrace();
        }
    }
}