浅复制和深复制示例

Question

Can i implement deep copy and shallow copy in following way?Is it correct? Any one on the following 2 clone methods would be placed in final code

public class Student{
  private String name;
  private DepartMent dept;


 //deep copy 
 public Object clone() throws CloneNotSupportedException{
  Student s =  (Student)super.clone();
  s.septDept((Department)dept.clone());
 }

 //shallow copy
 public Object clone() throws CloneNotSupportedException{
   return super.clone();
 }

}

Answer 1

Instead of attempting to implement Cloneable , which is considered broken , I would recommend you look at using copy constructors . A copy constructor takes an instance of its own declaring type as an argument, and copies that instance's fields to the new object. For example:

public Student(Student copyFrom) {
    this.name = copyFrom.name;
    this.dept = copyFrom.dept;
}

...

Student copy = new Student(originalStudent);

If Department also exposes a copy constructor, this will allow you to make a deep copy of Student . For example:

public Student(Student copyFrom) {
    this.name = copyFrom.name;
    this.dept = new Department(copyFrom.dept);
}

Although it's unclear from your question why a deep copy is necessary.

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For further reading, this article touches on both the issues of Cloneable and the limitations of copy constructors.

Answer 2

根据我的理解，是正确的，您只需要确保一件事，即在DepartMent类中覆盖clone（）方法。

Answer 3

您还可以使用dup（）方法，该方法还返回原始副本，具体取决于您尝试使用copy方法实现的代码类型...您只是在寻求建议，而没有提供足够的信息以正确指导您...在stackoverflow中也有很多回答问题的例子，因此您应该在寻求附加帮助之前先对它进行检查。