java深度拷贝实现

1. BeanUtils
spring提供了BeanUtils来实现对象的克隆，基本原理大体上就是使用反射机制来实现的。BeanUtils实现的并不是深度拷贝，不过BeanUtils可以拷贝两个不同的对象，这一点还是很不错的。


2，序列化clone
String json = JSON.toJSONString(list);
        List<User> list2 = JSON.parseArray(json,User.class);
通过序列化进行拷贝的方式效率很低 ，慎用

3，重新clone方法
public class Main {

    public static void main(String[] args) {

        Info info = new Info();
        info.setName("张三");
        info.setIDCard("111111");

        Person person1 = new Person();
        person1.setAdress("北京");
        person1.setInfo(info);

        System.out.println("clone()前person1："+person1.toString());

        Person person2 = null;
        try {
            person2 = (Person)person1.clone();
            person2.setAdress("河南");
            Info info1 = person2.getInfo();
            info1.setName("李四");
            info1.setIDCard("222222");
            person2.setInfo(info1);
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        System.out.println("clone()后person1："+person1.toString());
        System.out.println("clone()后person2："+person2.toString());

    }


    public static class Person implements Cloneable {

        private String adress;
        private Info info;

        public String getAdress() {
            return adress;
        }

        public void setAdress(String adress) {
            this.adress = adress;
        }

        public Info getInfo() {
            return info;
        }

        public void setInfo(Info info) {
            this.info = info;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "adress='" + adress + '\'' +
                    ", info=" + info +
                    '}';
        }

        public Object clone() throws CloneNotSupportedException{
            Person person = (Person) super.clone();
            person.info = (Info) info.clone();
            return person;
        }
    }

    public static class Info implements Cloneable {

        private String IDCard;
        private String name;

        public String getIDCard() {
            return IDCard;
        }

        public void setIDCard(String IDCard) {
            this.IDCard = IDCard;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        @Override
        public String toString() {
            return "Info{" +
                    "IDCard='" + IDCard + '\'' +
                    ", name='" + name + '\'' +
                    '}';
        }

        public Object clone() throws CloneNotSupportedException{
            return super.clone();
        }
    }


}



打印结果：

clone()前person1：Person{adress='北京', info=Info{IDCard='111111', name='张三'}}
clone()后person1：Person{adress='北京', info=Info{IDCard='111111', name='张三'}}
clone()后person2：Person{adress='河南', info=Info{IDCard='222222', name='李四'}}