Java的Clone简要

对于一个普通的对象来说，如果实现Cloneable接口，并重写clone方法可以实现对象的深拷贝。

但是对于List/Set等集合来说不管是用集合的clone方法还是对象的clone方法都是浅拷贝，即指针的引用，如果要实现java集合的深拷贝必须将对象实现Serializable接口后写一个深拷贝方法才行。

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

public class test {
    public static void main(String[] args) {
        List<Human> sdf = new ArrayList<Human>();
        sdf.add(new Human("sdf1", 100));
        sdf.add(new Human("sdf2", 200));

        List<Human> h3c = null;
        try {
            h3c = deepCopy(sdf);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Human h1 = h3c.get(0);
        h1.name = "h3c";

        System.out.println(sdf.get(0).name + "-" + sdf.get(0).age);
        System.out.println(h3c.get(0).name + "-" + h3c.get(0).age);
    }

    static class Human implements Serializable {
        String name;
        int age;

        public Human(String n, int a) {
            this.name = n;
            this.age = a;
        }

    }

    //关键代码 执行序列化和反序列化  进行深度拷贝
    public static <T> List<T> deepCopy(List<T> src) throws IOException, ClassNotFoundException {
        ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
        ObjectOutputStream out = new ObjectOutputStream(byteOut);
        out.writeObject(src);  

        ByteArrayInputStream byteIn = new ByteArrayInputStream(byteOut.toByteArray());
        ObjectInputStream in = new ObjectInputStream(byteIn);
        @SuppressWarnings("unchecked")
        List<T> dest = (List<T>) in.readObject();
        return dest;
    }
}