Java对象转换的深拷贝实现方案

import java.io.*;

public class DeepCopyUtil {

    @SuppressWarnings("unchecked")
    public static <T extends Serializable> T deepCopy(T obj) {
        try {
            // 写入字节流
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(obj);

            // 从字节流中读取
            ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(bis);
            return (T) ois.readObject();

        } catch (IOException | ClassNotFoundException e) {
            // 实际项目中可能需要更细致的异常处理
            System.err.println("深拷贝失败: " + e.getMessage());
            throw new RuntimeException("深拷贝操作失败", e);
        }
    }

    // 示例类
    public static class Address implements Serializable {
        private static final long serialVersionUID = 1L;
        private String city;
        private String street;

        public Address(String city, String street) {
            this.city = city;
            this.street = street;
        }

        public String getCity() { return city; }
        public void setCity(String city) { this.city = city; }
        public String getStreet() { return street; }
        public void setStreet(String street) { this.street = street; }

        @Override
        public String toString() {
            return "Address{" + "city='" + city + '\'' + ", street='" + street + '\'' + '}';
        }
    }

    public static class Person implements Serializable {
        private static final long serialVersionUID = 1L;
        private String name;
        private int age;
        private Address address; // 引用类型

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

        public String getName() { return name; }
        public void setName(String name) { this.name = name; }
        public int getAge() { return age; }
        public void setAge(int age) { this.age = age; }
        public Address getAddress() { return address; }
        public void setAddress(Address address) { this.address = address; }

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

    public static void main(String[] args) {
        Address originalAddress = new Address("北京", "朝阳区");
        Person originalPerson = new Person("张三", 30, originalAddress);

        System.out.println("原始对象: " + originalPerson);

        // 执行深拷贝
        Person copiedPerson = DeepCopyUtil.deepCopy(originalPerson);
        System.out.println("拷贝对象: " + copiedPerson);

        // 修改拷贝对象的内部引用
        copiedPerson.getAddress().setStreet("海淀区");
        copiedPerson.setName("李四");

        System.out.println("修改后原始对象: " + originalPerson);
        System.out.println("修改后拷贝对象: " + copiedPerson);

        // 验证是否是深拷贝
        System.out.println("原始地址对象和拷贝地址对象是否是同一个引用: " + (originalPerson.getAddress() == copiedPerson.getAddress()));
    }
}

// 假设有上面的Address类，但它不再需要实现Serializable
// public class Address { ... }

public class PersonWithManualCopy {
    private String name;
    private int age;
    private DeepCopyUtil.Address address; // 使用上面的Address类

    public PersonWithManualCopy(String name, int age, DeepCopyUtil.Address address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    // 拷贝构造器实现深拷贝
    public PersonWithManualCopy(PersonWithManualCopy other) {
        this.name = other.name; // String是不可变的，直接赋值即可
        this.age = other.age; // 基本类型直接赋值
        // 对于可变引用类型，必须创建新实例并拷贝其内容
        this.address = new DeepCopyUtil.Address(other.address.getCity(), other.address.getStreet());
    }

    // 或者提供一个深拷贝方法
    public PersonWithManualCopy deepCopy() {
        return new PersonWithManualCopy(this.name, this.age,
                new DeepCopyUtil.Address(this.address.getCity(), this.address.getStreet()));
    }

    // Getters and Setters (略)
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public int getAge() { return age; }
    public void setAge(int age) { this.age = age; }
    public DeepCopyUtil.Address getAddress() { return address; }
    public void setAddress(DeepCopyUtil.Address address) { this.address = address; }

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

    public static void main(String[] args) {
        DeepCopyUtil.Address originalAddress = new DeepCopyUtil.Address("上海", "浦东新区");
        PersonWithManualCopy originalPerson = new PersonWithManualCopy("王五", 25, originalAddress);

        System.out.println("原始对象: " + originalPerson);

        // 使用拷贝构造器
        PersonWithManualCopy copiedPerson = new PersonWithManualCopy(originalPerson);
        // 或者使用deepCopy方法
        // PersonWithManualCopy copiedPerson = originalPerson.deepCopy();

        System.out.println("拷贝对象: " + copiedPerson);

        copiedPerson.getAddress().setStreet("闵行区");
        copiedPerson.setName("赵六");

        System.out.println("修改后原始对象: " + originalPerson);
        System.out.println("修改后拷贝对象: " + copiedPerson);

        System.out.println("原始地址对象和拷贝地址对象是否是同一个引用: " + (originalPerson.getAddress() == copiedPerson.getAddress()));
    }
}