【137期】面試官：問點兒基礎(chǔ)的，你能說說Java深拷貝和淺拷貝區(qū)別嗎
閱讀本文大概需要 4 分鐘。
作者：riemann
blog.csdn.net/riemann_/article/details/87217229
一、拷貝的引入
（1）、引用拷貝
創(chuàng)建一個指向?qū)ο蟮囊米兞康目截悺?/p>
Teacher?teacher?=?new?Teacher("Taylor",26);
Teacher?otherteacher?=?teacher;
System.out.println(teacher);
System.out.println(otherteacher);
blog.Teacher@355da254
blog.Teacher@355da254
（2）、對象拷貝
Teacher?teacher?=?new?Teacher("Swift",26);?
Teacher?otherteacher?=?(Teacher)teacher.clone();?
System.out.println(teacher);
System.out.println(otherteacher);
blog.Teacher@355da254
blog.Teacher@4dc63996
注：深拷貝和淺拷貝都是對象拷貝
二、淺拷貝
（1）、定義
（2）、淺拷貝實例
package?com.test;
public?class?ShallowCopy?{
????public?static?void?main(String[]?args)?throws?CloneNotSupportedException?{
????????Teacher?teacher?=?new?Teacher();
????????teacher.setName("riemann");
????????teacher.setAge(27);
????????Student2?student1?=?new?Student2();
????????student1.setName("edgar");
????????student1.setAge(18);
????????student1.setTeacher(teacher);
????????Student2?student2?=?(Student2)?student1.clone();
????????System.out.println("拷貝后");
????????System.out.println(student2.getName());
????????System.out.println(student2.getAge());
????????System.out.println(student2.getTeacher().getName());
????????System.out.println(student2.getTeacher().getAge());
????????System.out.println("修改老師的信息后-------------");
????????//?修改老師的信息
????????teacher.setName("Games");
????????System.out.println(student1.getTeacher().getName());
????????System.out.println(student2.getTeacher().getName());
????}
}
class?Teacher?implements?Cloneable?{
????private?String?name;
????private?int?age;
????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;
????}
}
class?Student2?implements?Cloneable?{
????private?String?name;
????private?int?age;
????private?Teacher?teacher;
????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?Teacher?getTeacher()?{
????????return?teacher;
????}
????public?void?setTeacher(Teacher?teacher)?{
????????this.teacher?=?teacher;
????}
????public?Object?clone()?throws?CloneNotSupportedException?{
????????Object?object?=?super.clone();
????????return?object;
????}
}
拷貝后
edgar
18
riemann
27
修改老師的信息后-------------
Games
Games
三、深拷貝
（1）、定義
（2）、深拷貝實例
package?com.test;
public?class?DeepCopy?{
????public?static?void?main(String[]?args)?throws?CloneNotSupportedException?{
????????Teacher2?teacher?=?new?Teacher2();
????????teacher.setName("riemann");
????????teacher.setAge(27);
????????Student3?student1?=?new?Student3();
????????student1.setName("edgar");
????????student1.setAge(18);
????????student1.setTeacher(teacher);
????????Student3?student2?=?(Student3)?student1.clone();
????????System.out.println("拷貝后");
????????System.out.println(student2.getName());
????????System.out.println(student2.getAge());
????????System.out.println(student2.getTeacher().getName());
????????System.out.println(student2.getTeacher().getAge());
????????System.out.println("修改老師的信息后-------------");
????????//?修改老師的信息
????????teacher.setName("Games");
????????System.out.println(student1.getTeacher().getName());
????????System.out.println(student2.getTeacher().getName());
????}
}
class?Teacher2?implements?Cloneable?{
????private?String?name;
????private?int?age;
????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?Object?clone()?throws?CloneNotSupportedException?{
????????return?super.clone();
????}
}
class?Student3?implements?Cloneable?{
????private?String?name;
????private?int?age;
????private?Teacher2?teacher;
????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?Teacher2?getTeacher()?{
????????return?teacher;
????}
????public?void?setTeacher(Teacher2?teacher)?{
????????this.teacher?=?teacher;
????}
????public?Object?clone()?throws?CloneNotSupportedException?{
????????//?淺復(fù)制時：
????????//?Object?object?=?super.clone();
????????//?return?object;
????????//?改為深復(fù)制：
????????Student3?student?=?(Student3)?super.clone();
????????//?本來是淺復(fù)制，現(xiàn)在將Teacher對象復(fù)制一份并重新set進來
????????student.setTeacher((Teacher2)?student.getTeacher().clone());
????????return?student;
????}
}
拷貝后
edgar
18
riemann
27
修改老師的信息后-------------
Games
riemann
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