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;
	}
}