Java 開発: リフレクション メカニズムを使用してオブジェクトのシリアル化と逆シリアル化を実装する方法

public class Person {
    private String name;
    private int age;

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

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

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

    public void setAge(int age) {
        this.age = age;
    }
}

import java.lang.reflect.Field;

public class SerializationUtil {
    public static byte[] serialize(Object obj) throws Exception {
        Class<?> cls = obj.getClass();
        Field[] fields = cls.getDeclaredFields();

        byte[] bytes = new byte[fields.length * 4];
        for (int i = 0; i < fields.length; i++) {
            fields[i].setAccessible(true);
            if (fields[i].getType() == int.class) {
                int value = fields[i].getInt(obj);
                int offset = i * 4;
                bytes[offset] = (byte) (value >> 24);
                bytes[offset + 1] = (byte) (value >> 16);
                bytes[offset + 2] = (byte) (value >> 8);
                bytes[offset + 3] = (byte) value;
            }
        }
        return bytes;
    }

    public static Object deserialize(byte[] bytes, Class<?> cls) throws Exception {
        Object obj = cls.newInstance();
        Field[] fields = cls.getDeclaredFields();
        for (int i = 0; i < fields.length; i++) {
            fields[i].setAccessible(true);
            if (fields[i].getType() == int.class) {
                int offset = i * 4;
                int value = (bytes[offset] << 24) | ((bytes[offset + 1] & 0xFF) << 16) | ((bytes[offset + 2] & 0xFF) << 8) | (bytes[offset + 3] & 0xFF);
                fields[i].setInt(obj, value);
            }
        }
        return obj;
    }
}

public class Main {
    public static void main(String[] args) {
        try {
            Person person = new Person("Alice", 25);

            // 序列化
            byte[] bytes = SerializationUtil.serialize(person);
            // 反序列化
            Person deserializedPerson = (Person) SerializationUtil.deserialize(bytes, Person.class);

            System.out.println("Name: " + deserializedPerson.getName());
            System.out.println("Age: " + deserializedPerson.getAge());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Name: Alice
Age: 25