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java如何创建深拷贝

2026-03-18 22:59:56Java

创建深拷贝的方法

在Java中创建深拷贝需要确保对象及其所有嵌套对象都被完全复制，而不是仅复制引用。以下是几种常见方法：

实现Cloneable接口并重写clone方法

通过实现Cloneable接口并重写clone()方法，可以手动实现深拷贝。需要递归调用嵌套对象的clone()方法。

class Person implements Cloneable {
    private String name;
    private Address address;

    @Override
    protected Object clone() throws CloneNotSupportedException {
        Person cloned = (Person) super.clone();
        cloned.address = (Address) address.clone(); // 递归调用
        return cloned;
    }
}

class Address implements Cloneable {
    private String city;

    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

使用序列化与反序列化

通过将对象序列化为字节流再反序列化，可以实现完全的深拷贝。需要确保所有相关类都实现Serializable接口。

import java.io.*;

public class DeepCopyUtil {
    public static <T extends Serializable> T deepCopy(T object) {
        try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
             ObjectOutputStream oos = new ObjectOutputStream(baos)) {
            oos.writeObject(object);
            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(bais);
            return (T) ois.readObject();
        } catch (IOException | ClassNotFoundException e) {
            throw new RuntimeException("Deep copy failed", e);
        }
    }
}

使用第三方库

Apache Commons Lang库的SerializationUtils提供了简单的深拷贝方法：

import org.apache.commons.lang3.SerializationUtils;

Person original = new Person();
Person copied = SerializationUtils.clone(original);

手动复制构造函数

为每个类创建复制构造函数，显式地复制所有字段：

java如何创建深拷贝

class Person {
    private String name;
    private Address address;

    public Person(Person other) {
        this.name = other.name;
        this.address = new Address(other.address); // 调用嵌套对象的复制构造函数
    }
}

class Address {
    private String city;

    public Address(Address other) {
        this.city = other.city;
    }
}