Java深复制与浅复制&Clone

http://zzqrj.iteye.com/blog/572562

 

 

浅复制（浅克隆） : 浅复制仅仅复制所考虑的对象，而不复制它所引用的对象。   

     深复制（深克隆）：深复制把要复制的对象所引用的对象都复制了一遍。   

    Java 中对象的克隆 , 为了获取对象的一份拷贝，我们可以利用 Object 类的 clone() 方法。必须要遵循下面三点   

     1. 在派生类中覆盖基类的 clone() 方法，并声明为 public 【 Object 类中的 clone() 方法为 protected 的】。   

     2. 在派生类的 clone() 方法中，调用 super.clone() 。   

     3. 在派生类中实现Cloneable 接口。

     Object 类里的 clone 方法是浅复制（浅克隆）

浅复制：

 public   class  CloneTest {
     public   static   void  main(String[] args)  throws  CloneNotSupportedException {
         Teacher teacher=new  Teacher();
         teacher.setAge(40 );
         teacher.setName("Teacher Zhang" );

         Student student1=new  Student();
         student1.setAge(20 );
         student1.setName("zhangsan" );
         student1.setTeacher(teacher);

         Student student2=(Student)student1.clone();
         System.out.println(student2.getAge());
         System.out.println(student2.getName());
         System.out.println(student2.getTeacher().getAge());
         System.out.println(student2.getTeacher().getName());

         System.out.println("~~~~~~~~~~~~~~~~~~~~~~~" );
         System.out.println(student1.getTeacher().getAge());
         System.out.println(student1.getTeacher().getName());

         student2.setAge(18 );
         student2.getTeacher().setAge(50 ); //浅复制针对对象的引用没有重新开辟新的空间
         student2.getTeacher().setName("Teacher Li" );     //改变值后相应的都改变

         System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~" );
         System.out.println(student1.getAge());
         System.out.println(student1.getTeacher().getAge());
         System.out.println(student1.getTeacher().getName());
     }
 }
 class  Teacher{
     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;}
 }
 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;}
     public  Object clone() throws  CloneNotSupportedException{
         return   super .clone();
     }
 }

public class CloneTest {
	public static void main(String[] args) throws CloneNotSupportedException {
		Teacher teacher=new Teacher();
		teacher.setAge(40);
		teacher.setName("Teacher Zhang");
		
		Student student1=new Student();
		student1.setAge(20);
		student1.setName("zhangsan");
		student1.setTeacher(teacher);
		
		Student student2=(Student)student1.clone();
		System.out.println(student2.getAge());
		System.out.println(student2.getName());
		System.out.println(student2.getTeacher().getAge());
		System.out.println(student2.getTeacher().getName());
		
		System.out.println("~~~~~~~~~~~~~~~~~~~~~~~");
		System.out.println(student1.getTeacher().getAge());
		System.out.println(student1.getTeacher().getName());
		
		student2.setAge(18);
		student2.getTeacher().setAge(50);//浅复制针对对象的引用没有重新开辟新的空间
		student2.getTeacher().setName("Teacher Li");	//改变值后相应的都改变
		
		System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~");
		System.out.println(student1.getAge());
		System.out.println(student1.getTeacher().getAge());
		System.out.println(student1.getTeacher().getName());
	}
}
class Teacher{
	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;}
}
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;}
	public Object clone()throws CloneNotSupportedException{
		return super.clone();
	}
}

 

深复制：

 public   class  DeepCloneTest {
 public   static   void  main(String[] args)  throws  CloneNotSupportedException {
         Teacher teacher = new  Teacher();
         teacher.setAge(40 );
         teacher.setName("Teacher Zhang" );

         Student student1 = new  Student();
         student1.setAge(20 );
         student1.setName("zhangsan" );
         student1.setTeacher(teacher);

         Student student2 = (Student) student1.clone();
         System.out.println(student2.getAge());
         System.out.println(student2.getName());
         System.out.println(student2.getTeacher().getAge());
         System.out.println(student2.getTeacher().getName());

         System.out.println("~~~~~~~~~~~~~~~~~~~~~~~" );
         System.out.println(student1.getTeacher().getAge());
         System.out.println(student1.getTeacher().getName());
         student2.setAge(18 );
         student2.getTeacher().setAge(50 );  //浅复制针对对象的引用没有重新开辟新的空间
         student2.getTeacher().setName("Teacher Li" );  // 改变值后相应的都改变

         System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~" );
         System.out.println(student1.getAge());
         System.out.println(student1.getTeacher().getAge());
         System.out.println(student1.getTeacher().getName());
     }
 }
 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;}
     public  Object clone()  throws  CloneNotSupportedException {
         return   super .clone();
     }
 }

 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;}
     public  Object clone()  throws  CloneNotSupportedException {
         Student student = (Student) super .clone();
         student.setTeacher((Teacher) (student.getTeacher().clone()));
         return  student;
     }
 }

public class DeepCloneTest {
public static void main(String[] args) throws CloneNotSupportedException {
		Teacher teacher = new Teacher();
		teacher.setAge(40);
		teacher.setName("Teacher Zhang");

		Student student1 = new Student();
		student1.setAge(20);
		student1.setName("zhangsan");
		student1.setTeacher(teacher);

		Student student2 = (Student) student1.clone();
		System.out.println(student2.getAge());
		System.out.println(student2.getName());
		System.out.println(student2.getTeacher().getAge());
		System.out.println(student2.getTeacher().getName());

		System.out.println("~~~~~~~~~~~~~~~~~~~~~~~");
		System.out.println(student1.getTeacher().getAge());
		System.out.println(student1.getTeacher().getName());
		student2.setAge(18);
		student2.getTeacher().setAge(50); //浅复制针对对象的引用没有重新开辟新的空间
		student2.getTeacher().setName("Teacher Li"); // 改变值后相应的都改变

		System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~");
		System.out.println(student1.getAge());
		System.out.println(student1.getTeacher().getAge());
		System.out.println(student1.getTeacher().getName());
	}
}
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;}
	public Object clone() throws CloneNotSupportedException {
		return super.clone();
	}
}

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;}
	public Object clone() throws CloneNotSupportedException {
		Student student = (Student) super.clone();
		student.setTeacher((Teacher) (student.getTeacher().clone()));
		return student;
	}
}