浅谈深拷贝和浅拷贝

package com.wgw.entities;

public class MyDate {
	private int year;
	private int month;
	private int day;
	
	public int getYear() {
		return year;
	}


	public void setYear(int year) {
		this.year = year;
	}


	public int getMonth() {
		return month;
	}


	public void setMonth(int month) {
		this.month = month;
	}


	public int getDay() {
		return day;
	}


	public void setDay(int day) {
		this.day = day;
	}


	public void set(int year,int month,int day) {
		this.year = year;
		this.month = month;
		this.day = day;
	}
	
	
	public MyDate(MyDate d){
		d.set(d.year, d.month, d.day);
	}
	
	public MyDate(int year,int month,int day) {
		this.set(year, month, day);
	}
	
	public String toString() {
		return year + "年" + String.format("%02d",month) + "月" + String.format("%02d", day) + "日";
	}
	
	public boolean equals(MyDate d) {
		return this==d || d!=null &&this.year==d.year&&this.month==d.month&&this.day==d.day;
	}
	
}

package com.wgw.entities;

public class Person {
	private String name;
	private MyDate birthday;
	private String sex;
	
	public String getName() {
		return name;
	}

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

	public MyDate getBirthday() {
		return birthday;
	}

	public void setBirthday(MyDate birthday) {
		this.birthday = birthday;
	}

	public String isSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex = sex;
	}

	
	
	public Person(String name,MyDate birthday,String sex) {   //这样传参的时候不会new mydate
		this.set(name, birthday, sex);
		
	}
	
	public Person(Person p) { //深度拷贝的时候会New
		this(p.name,new MyDate(p.birthday),p.sex);
	}
	
//	public Person(Person p) { //深度拷贝的时候会New
//		this(p.name,p.birthday,p.sex);
//	}
	
	public void set(String name,MyDate birthday,String sex) {
		this.name = name;
		this.birthday = birthday;
		this.sex = sex;
	}
	
	public String toString() {
		return name + "," + birthday.toString() + sex;
	}
	
	public boolean equals(Person p) {
		return this==p||p.name ==this.name&&p.birthday == this.birthday && p.sex == this.sex;
	}
	

}

package com.wgw.test;

import com.wgw.entities.MyDate;
import com.wgw.entities.Person;

public class Test {
	public static void main(String[] args) {
		MyDate d1 = new MyDate(1997,9,20);
		MyDate d2 = new MyDate(2017,4,5);
		System.out.println(d1.toString());
		System.out.println(d2.toString());
		
		//打印p1内容
		Person p1 = new Person("Bob",d1,"男");
		System.out.println(p1.toString());
		
		//拷贝构造
		Person p2 = new Person(p1);
		System.out.println(p2.toString());
		//改变p2的内容，测试p1是否也跟着改变
		p2.getBirthday().set(1996,10,1);
		p2.setName("Mary");//浅构造的时候把这里注释,equals返回true
		p2.setSex("女");
		System.out.println(p2.toString());
		System.out.println(p1.toString());
		System.out.println(p2.equals(p1));//birth对象是不同的
		
		
//		p1.set("Alice", d2, "女");
//		System.out.println(p1.toString());
//		System.out.println(p2.toString());
//		
//		System.out.println(p2.equals(p1));//birth对象是不同的

		
//		d1.setYear(3010);
//		d1.toString();
//		p1.set("Jack", d1, "男");
//		
//		Person p3 = new Person("Jack", d1, "男");
//		System.out.println(p3.equals(p1));
		
		
	}
}

分别注释浅拷贝和深拷贝的结果：