java怎样实现对象的序列化与反序列化 java序列化操作的基础方法

java.io.Serializable

java.io.ObjectOutputStream

java.io.ObjectInputStream

import java.io.*;

// 1. 定义一个可序列化的类
class User implements Serializable {
    private static final long serialVersionUID = 1L; // 推荐显式定义
    private String name;
    private int age;
    private transient String password; // 标记为transient的字段不会被序列化

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

    @Override
    public String toString() {
        return "User{name='" + name + "', age=" + age + ", password='" + password + "'}";
    }

    // 省略getter/setter
    public String getName() { return name; }
    public int getAge() { return age; }
    public String getPassword() { return password; }
}

public class SerializationDemo {
    public static void main(String[] args) {
        User user = new User("张三", 30, "mySecretPass");
        String filePath = "user.ser"; // 序列化文件路径

        // 序列化
        try (FileOutputStream fileOut = new FileOutputStream(filePath);
             ObjectOutputStream out = new ObjectOutputStream(fileOut)) {
            out.writeObject(user);
            System.out.println("User对象已序列化到 " + filePath);
            System.out.println("原始对象: " + user);
        } catch (IOException i) {
            i.printStackTrace();
        }

        // 反序列化
        User deserializedUser = null;
        try (FileInputStream fileIn = new FileInputStream(filePath);
             ObjectInputStream in = new ObjectInputStream(fileIn)) {
            deserializedUser = (User) in.readObject();
            System.out.println("User对象已从 " + filePath + " 反序列化。");
            System.out.println("反序列化对象: " + deserializedUser);
            // 注意：transient字段的值为默认值
            System.out.println("反序列化后密码: " + deserializedUser.getPassword()); // 会是null
        } catch (IOException i) {
            i.printStackTrace();
        } catch (ClassNotFoundException c) {
            System.out.println("User class not found");
            c.printStackTrace();
        }
    }
}

password

null

transient

transient

transient

transient

null

false

static

Serializable

transient

static

Serializable

InvalidClassException

serialVersionUID

serialVersionUID

serialVersionUID

serialVersionUID

java.io.InvalidClassException

Serializable

serialVersionUID

serialVersionUID

private static final long serialVersionUID = 1L;

serialVersionUID

readObject()

writeObject()

Serializable

serialVersionUID

1L

ObjectOutputStream

ObjectInputStream