• 如何实现对象克隆?


    1). 实现Cloneable接口并重写Object类中的clone()方法;
    2). 实现Serializable接口,通过对象的序列化和反序列化实现克隆,可以实现真正的深度克隆,代码

    import java.io.ByteArrayInputStream;
    import java.io.ByteArrayOutputStream;
    import java.io.ObjectInputStream;
    import java.io.ObjectOutputStream;
     
    public class MyUtil {
     
        private MyUtil() {
            throw new AssertionError();
        }
     
        public static <T> T clone(T obj) throws Exception {
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bout);
            oos.writeObject(obj);
     
            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(bin);
            return (T) ois.readObject();
     
            // 说明:调用ByteArrayInputStream或ByteArrayOutputStream对象的close方法没有任何意义
            // 这两个基于内存的流只要垃圾回收器清理对象就能够释放资源,这一点不同于对外部资源(如文件流)的释放
        }
    }
    

     下面是测试代码:

    import java.io.Serializable;
     
    /**
     * 人类
     * @author 骆昊
     *
     */
    class Person implements Serializable {
        private static final long serialVersionUID = -9102017020286042305L;
     
        private String name;    // 姓名
        private int age;        // 年龄
        private Car car;        // 座驾
     
        public Person(String name, int age, Car car) {
            this.name = name;
            this.age = age;
            this.car = car;
        }
     
        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 Car getCar() {
            return car;
        }
     
        public void setCar(Car car) {
            this.car = car;
        }
     
        @Override
        public String toString() {
            return "Person [name=" + name + ", age=" + age + ", car=" + car + "]";
        }
     
    }
    
    	
    /**
     * 小汽车类
     * @author 骆昊
     *
     */
    class Car implements Serializable {
        private static final long serialVersionUID = -5713945027627603702L;
     
        private String brand;       // 品牌
        private int maxSpeed;       // 最高时速
     
        public Car(String brand, int maxSpeed) {
            this.brand = brand;
            this.maxSpeed = maxSpeed;
        }
     
        public String getBrand() {
            return brand;
        }
     
        public void setBrand(String brand) {
            this.brand = brand;
        }
     
        public int getMaxSpeed() {
            return maxSpeed;
        }
     
        public void setMaxSpeed(int maxSpeed) {
            this.maxSpeed = maxSpeed;
        }
     
        @Override
        public String toString() {
            return "Car [brand=" + brand + ", maxSpeed=" + maxSpeed + "]";
        }
     
    }
    
    	
    class CloneTest {
     
        public static void main(String[] args) {
            try {
                Person p1 = new Person("Hao LUO", 33, new Car("Benz", 300));
                Person p2 = MyUtil.clone(p1);   // 深度克隆
                p2.getCar().setBrand("BYD");
                // 修改克隆的Person对象p2关联的汽车对象的品牌属性
                // 原来的Person对象p1关联的汽车不会受到任何影响
                // 因为在克隆Person对象时其关联的汽车对象也被克隆了
                System.out.println(p1);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    
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  • 原文地址:https://www.cnblogs.com/gjack/p/8901693.html
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