Java 序列化和Java反射的底层原理及区别对比分析

import java.io.*;
// 实现Serializable接口
class User implements Serializable {
    private static final long serialVersionUID = 1L; // 版本号
    private String name;
    private transient int age; // transient修饰，不序列化
    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }
    @Override
    public String toString() {
        return "User{name='" + name + "', age=" + age + "}";
    }
}
public class SerializationDemo {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        // 序列化：对象→字节序列（存文件）
        User user = new User("Alice", 20);
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("user.ser"));
        oos.writeObject(user);
        oos.close();
        // 反序列化：字节序列→对象
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("user.ser"));
        User deserializedUser = (User) ois.readObject();
        ois.close();
        System.out.println(deserializedUser); // 输出：User{name='Alice', age=0}（age未序列化）
    }
}

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
class Person {
    private String name;
    private int age;
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    private void sayHello() {
        System.out.println("Hello, " + name);
    }
}
public class ReflectionDemo {
    public static void main(String[] args) throws Exception {
        // 1. 获取Class对象
        Class<?> personClass = Person.class;
        // 2. 通过反射创建对象（调用构造器）
        Constructor<?> constructor = personClass.getConstructor(String.class, int.class);
        Object person = constructor.newInstance("Bob", 25);
        // 3. 访问private属性
        Field nameField = personClass.getDeclaredField("name");
        nameField.setAccessible(true); // 打破封装
        System.out.println("Name: " + nameField.get(person)); // 输出：Name: Bob
        // 4. 调用private方法
        Method sayHelloMethod = personClass.getDeclaredMethod("sayHello");
        sayHelloMethod.setAccessible(true);
        sayHelloMethod.invoke(person); // 输出：Hello, Bob
    }
}