克隆Object的方法.
protected native Object clone() throws CloneNotSupportedException;
CloneNotSupportedException表示你必须为你要克隆的类实现Cloneable接口
public interface Cloneable
例子一,User类
package com.ming.test.three;
public class User implements Cloneable{
private String username;
private Integer age;
private int sex;
private Car car;
public User(String username,Integer age,int sex,Car car){
this.username = username;
this.age = age;
this.sex = sex;
this.car = car;
}
@Override
public boolean equals(Object obj) {
// TODO Auto-generated method stub
return super.equals(obj);
}
@Override
protected Object clone() throws CloneNotSupportedException {
// TODO Auto-generated method stub
User u = (User)super.clone();
//u.setUsername(new String(username));//在这里你可以进行重新生成注入进去
//u.setAge(new Integer(age));//在这里进行改良
//----如果是自定义类型
//u.setCar((Car)car.clone());//car 是你当前克隆对象的属性,而且Car必须实现Cloneable接口
return u;
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
Car 类
package com.ming.test.three;
import java.io.Serializable;
/**
* @author user
*
*/
public class Car implements Cloneable{
@Override
protected Object clone() throws CloneNotSupportedException {
// TODO Auto-generated method stub
return super.clone();
}
}
测试类,Test
package com.ming.test.three;
package com.ming.test.three;
public class Test {
public static void main(String[] args) throws CloneNotSupportedException {
User u = new User("jacky",11,1,new Car());
User u1 = (User)u.clone();//克隆一份
System.out.println(u==u1);//false 表示重新生成了一份
System.out.println(u.getUsername()==u1.getUsername());//true 表示引用类型 只是copy了栈的引用为重新复制 这为浅克隆
System.out.println(u.getCar()==u1.getCar());//true
}
}
深克隆的实现方式,对于引用类型的复制,必须要深度克隆,一下有俩种方式实现。
1.在你需要clone的类中
@Override
protected Object clone() throws CloneNotSupportedException {
// TODO Auto-generated method stub
User u = (User)super.clone();
u.setUsername(new String(username));//在这里你可以进行重新生成注入进去
u.setAge(new Integer(age));//在这里进行改良
//----如果是自定义类型
u.setCar(car.clone());//car 是你当前克隆对象的属性,而且Car必须实现Cloneable接口
return u;
}
2.实现 implements Serializable
User类
package com.ming.test.three;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class User implements Cloneable, Serializable{
/** */
private static final long serialVersionUID = 8574879580125565714L;
private String username;
private Integer age;
private int sex;
private Car car;
public User(String username,Integer age,int sex,Car car){
this.username = username;
this.age = age;
this.sex = sex;
this.car = car;
}
@Override
public boolean equals(Object obj) {
// TODO Auto-generated method stub
return super.equals(obj);
}
@Override
protected Object clone() throws CloneNotSupportedException {
// TODO Auto-generated method stub
User u = (User)super.clone();
// u.setUsername(new String(username));//在这里你可以进行重新生成注入进去
//u.setAge(new Integer(age));//在这里进行改良
//----如果是自定义类型
// u.setCar((Car)car.clone());//car 是你当前克隆对象的属性,而且Car必须实现Cloneable接口
return u;
}
public Object deepCopy() throws IOException, ClassNotFoundException{
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos;
ObjectInputStream ois = null;
oos = new ObjectOutputStream(bos);
oos.writeObject(this);
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ois = new ObjectInputStream(bis);
return ois.readObject();
}
public Car getCar() {
return car;
}
public void setCar(Car car) {
this.car = car;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
Car类
package com.ming.test.three;
import java.io.Serializable;
/**
* @author user
*
*/
public class Car implements Cloneable, Serializable{
/** */
private static final long serialVersionUID = -740464901844332572L;
@Override
protected Object clone() throws CloneNotSupportedException {
// TODO Auto-generated method stub
return super.clone();
}
}
Test类
package com.ming.test.three;
public class Test {
public static void main(String[] args) throws CloneNotSupportedException {
//-----深度克隆
Car car = new Car();
User u2 = new User("ming",111,11,car);
try {
User u3 = (User) u2.deepCopy();
System.out.println(u3==u2);//false
System.out.println(u3.getCar()==u2.getCar());//false
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}