本文将简单介绍java中对象的浅拷贝和深拷贝知识点！
Java中通过对象的clone方法可以复制对象，而clone方法在Object里定义的，是一个protected类型的方法，只有实现了Cloneable（java.lang.Cloneable）接口，，该类对象才能调用clone方法，否则抛出异常。
1.浅拷贝
对象经过浅拷贝，基本类型的属性会拷贝值，引用类型的属性会拷贝引用。因此修改引用类型的属性值会影响另一对象！
示例代码
package com.test;public class ShallowCopyTest {static class Country{String name;Country(String name){this.name = name;}}static class Person implements Cloneable{String name;int age;Country country;Person(String name, int age, Country country){this.name = name;this.age = age;this.country = country;}@Overridepublic Object clone() throws CloneNotSupportedException {return super.clone();}}/** * @param args */public static void main(String[] args) {Person zhangsan = new Person("zhangsan", 24, new Country("China"));System.out.println("zhangsan – " + zhangsan.name + ":" + zhangsan.age + ":" + zhangsan.country.name);try {Person tom = (Person) zhangsan.clone();System.out.println("tom – " + tom.name + ":" + tom.age + ":" + tom.country.name);tom.name = "tom";tom.age = 21;tom.country.name = "USA";System.out.println("———-after———-");System.out.println("zhangsan – " + zhangsan.name + ":" + zhangsan.age + ":" + zhangsan.country.name);System.out.println("tom – " + tom.name + ":" + tom.age + ":" + tom.country.name);} catch (CloneNotSupportedException e) {e.printStackTrace();}}}
打印结果zhangsan – zhangsan:24:Chinatom – zhangsan:24:China———-after———-zhangsan – zhangsan:24:USAtom – tom:21:USA
2.深拷贝
对象经过深拷贝，基本类型的属性会拷贝值，引用类型所指向的对象内容也会拷贝一份。因此修改引用类型的属性值不会影响另一对象！
示例代码
package com.test;public class DeepCopyTest {static class Country implements Cloneable{String name;Country(String name){this.name = name;}@Overridepublic Object clone() throws CloneNotSupportedException {return super.clone();}}static class Person implements Cloneable{String name;int age;Country country;Person(String name, int age, Country country){this.name = name;this.age = age;this.country = country;}@Overridepublic Object clone() throws CloneNotSupportedException {Person obj = (Person) super.clone();obj.country = (Country) this.country.clone();return obj;}}/** * @param args */public static void main(String[] args) {Person zhangsan = new Person("zhangsan", 24, new Country("China"));System.out.println("zhangsan – " + zhangsan.name + ":" + zhangsan.age + ":" + zhangsan.country.name);try {Person tom = (Person) zhangsan.clone();System.out.println("tom – " + tom.name + ":" + tom.age + ":" + tom.country.name);tom.name = "tom";tom.age = 21;tom.country.name = "USA";System.out.println("———-after———-");System.out.println("zhangsan – " + zhangsan.name + ":" + zhangsan.age + ":" + zhangsan.country.name);System.out.println("tom – " + tom.name + ":" + tom.age + ":" + tom.country.name);} catch (CloneNotSupportedException e) {e.printStackTrace();}}}
打印结果
zhangsan – zhangsan:24:Chinatom – zhangsan:24:China———-after———-zhangsan – zhangsan:24:Chinatom – tom:21:USA
一个真正的人对困难的回答是战斗，
