java的克隆

所谓复制就是将一份东西拷贝一份，在java中有浅复制和深复制的概念
浅复制是指被复制的对象与原对象有相同的成员变量值，但是其引用类型的变量还是指的同
一个对象，而深复制是对原对象及其成员变量引用的对象也复制了一遍

复制产生的条件要满足如下
第一要实现Cloneable接口，重写Object类的clone方法并将其protect修饰符修改为public，调用Object类中的clone方法super.clone()
有人可能会问为什么一定要调用super.clone()
在运行时刻，Object中的clone方法识别出你要复制的是哪一个对象，然后为此对象分配空
间，并进行对象的复制，将原始对象的内容复制到新对象的存储空间中
下面是一个深复制的例子

package com.lamp.test;

public class CloneTest {
	public static void main(String[] args) throws Exception {
		Teacher teacher = new Teacher();
		teacher.setAge(50);
		teacher.setName("胡老师");

		Student student = new Student();
		student.setAge(22);
		student.setName("zhansan");
		student.setTeacher(teacher);

		Student student2 = (Student)student.clone();
		student2.getTeacher().setName("吴老师");		//由于是深复制，所以此处对teacher成员变量的修改不会对student有影响
		System.out.println(student2.getName());
		System.out.println(student.getTeacher().getName());
	}
}

class Student implements Cloneable {
	private int age;

	private String name;

	private Teacher teacher;

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getName() {
		return name;
	}

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

	public Teacher getTeacher() {
		return teacher;
	}

	public void setTeacher(Teacher teacher) {
		this.teacher = teacher;
	}

	@Override
	public Object clone() throws CloneNotSupportedException {	//重写Object的clone方法，并要将其protect修饰符改为public
		Student student = (Student) super.clone();
		student.setTeacher((Teacher) student.getTeacher().clone());		

//由于Object的clone为浅复制，所以在复制对象的引用时候，也要将引用所指的对象复制一遍
		return student;
	}
}

class Teacher implements Cloneable {
	private int age;

	private String name;

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public String getName() {
		return name;
	}

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

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

}