史上最清晰易懂的JAVA深克隆和浅克隆讲解

深入浅出了解面向对象的深克隆和浅克隆

阅读本文需要一定的面向对象基础和JavaIO流的相应知识！

深克隆(要实现深克隆被克隆类以及被克隆类的引用必须实现Serializable接口)

(未实现接口会抛出NotSerializableException异常)

定义:被复制对象的所有变量都含有与原来的对象相同的值，除去那些引用其他对象的变量。那些引用其他对象的变量将指向被复制过的新对象，而不再是原有的那些被引用的对象。深克隆的是实现实际上是对对象的序列化和反序列化

浅克隆(要实现浅克隆被克隆的类必须实现Cloneable接口)

(未实现接口会跑出CloneNotSupportedException异常)

定义:被复制对象的所有变量都含有与原来的对象相同的值，而所有的对其他对象的引用仍然指向原来的对象。

详细讲解代及实现码如下

实现类：

package com.xiaoqiang;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
/**
 * 本案例配合上文解说
 * 详细讲解java深克隆浅克隆的区别
 * @author xiaoqiang
 * @Time 2017年5月5日
 */
public class Student implements Cloneable,Serializable{
    private String name;
    private int age;
    private Date birthday;
    public Student(){
        super();
    }
    public Student(String name, int age, Date birthday) {
        super();
        this.name = name;
        this.age = age;
        this.birthday = birthday;
    }
    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 Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", birthday="
                + birthday + "]";
    }
    /**
     * 完成浅克隆类需实现Cloneable接口
     * @param student
     * @return Object
     */
    public Object shallowClone(Student student){
        try {
            return student.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return null;
    }
    /**
     * 完成深克隆被克隆的类和类的引用类
     * 均实现Serializable接口
     * @param student
     * @return Object
     */
    public Object deepClone(Student student){
        /*
         *本次实现深克隆使用 ByteArrayOutputStream 
         * 和ByteArrayInputStream 
         *作为复制过程中字符数组存储中介
         */
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos =null;
        ObjectInputStream ois = null;
        try {
            //将bos作为收集字节数组中介
            oos= new ObjectOutputStream(bos);
            //将传入参数student类写入bos中
            oos.writeObject(student);
            //将读取到数据传入ObjectInputStream
            ois = new ObjectInputStream(new ByteArrayInputStream(bos.toByteArray()));
            return ois.readObject();
        } catch (IOException | ClassNotFoundException e) {
            //JDK 1.7后引入 可以同时用| 优化代码可读性
            e.printStackTrace();
            return null;
        } finally{
            try {
                bos.close();
                oos.close();
                ois.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    public static void main(String[] args) {
        Student student = new Student("小强",,new Date("1997","06","13"));
        System.out.println("原student类   "+student);
        //浅克隆对象shallowCloneStudent
        Student shallowCloneStudent = (Student) student.shallowClone(student);
        System.out.println("浅克隆出来的student   "+shallowCloneStudent);
        System.out.println("浅克隆和深克隆对象对比   "+shallowCloneStudent.equals(student));
        System.out.println("浅克隆Date和深克隆Date类引用是否相同   "+shallowCloneStudent.getBirthday().equals(student.getBirthday()));
        //深克隆对象deepCloneStudent
        Student deepCloneStudent = (Student) student.deepClone(student);
        System.out.println("深克隆出来的student   "+deepCloneStudent);
        System.out.println("深克隆和深克隆对象对比   "+deepCloneStudent.equals(student));
        System.out.println("深克隆Date和深克隆Date类引用是否相同   "+deepCloneStudent.getBirthday().equals(student.getBirthday()));

    }
}   
           

引用类

package com.xiaoqiang;

import java.io.Serializable;
/**
 * @author xiaoqiang
 * @Time 2017年5月5日
 */
public class Date implements Serializable{
    private String year;
    private String month;
    private String day;
    public Date(){}
    public Date(String year, String month, String date) {
        super();
        this.year = year;
        this.month = month;
        this.day = date;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getMonth() {
        return month;
    }
    public void setMonth(String month) {
        this.month = month;
    }
    public String getDate() {
        return day;
    }
    public void setDate(String date) {
        this.day = date;
    }
    @Override
    public String toString() {
        return year+"年"+month+"月"+day+"日";
    }
}