基本介绍
类图
代码演示
package com.hy.prototype.improve;
import lombok.AllArgsConstructor;
import lombok.Data;
/**
* @author hanyong
* @date 2020/11/6 23:12
*/
@Data
@AllArgsConstructor
public class Sheep implements Cloneable {
private String name;
private int age;
private String color;
@Override
protected Object clone() {
Sheep sheep = null;
try {
sheep = (Sheep) super.clone();
} catch (Exception e) {
System.out.println(e.getMessage());
}
return sheep;
}
}
package com.hy.prototype.improve;
/**
* @author hanyong
* @date 2020/11/6 23:21
*/
public class Client {
public static void main(String[] args) {
System.out.println("原型模式完成对象的创建");
// TODO Auto-generated method stub
Sheep sheep = new Sheep("tom", 1, "白色");
Sheep sheep2 = (Sheep) sheep.clone(); //克隆
Sheep sheep3 = (Sheep) sheep.clone(); //克隆
Sheep sheep4 = (Sheep) sheep.clone(); //克隆
Sheep sheep5 = (Sheep) sheep.clone(); //克隆
System.out.println(sheep==sheep2);
System.out.println(sheep.equals(sheep2));
System.out.println(sheep+""+sheep.hashCode());
System.out.println(sheep2+""+sheep2.hashCode());
System.out.println(sheep3+""+sheep3.hashCode());
System.out.println(sheep4);
System.out.println(sheep5);
}
}
当对象有属性非基本类型而是对象的时候，拷贝不会对对象属性进行拷贝，而是引用初始对象的的属性对象的地址
代码演示
package com.hy.prototype.improve;
import lombok.*;
/**
* @author hanyong
* @date 2020/11/6 23:12
*/
@AllArgsConstructor
@ToString
public class Sheep implements Cloneable {
@Setter
@Getter
private String name;
@Setter
@Getter
private int age;
@Setter
@Getter
private String color;
public Sheep freend ;
public Sheep(String name, int age, String color) {
this.name = name;
this.age = age;
this.color = color;
}
@Override
protected Object clone() {
Sheep sheep = null;
try {
sheep = (Sheep) super.clone();
} catch (Exception e) {
System.out.println(e.getMessage());
}
return sheep;
}
}
package com.hy.prototype.improve;
/**
* @author hanyong
* @date 2020/11/6 23:21
*/
public class Client {
public static void main(String[] args) {
System.out.println("原型模式完成对象的创建");
// TODO Auto-generated method stub
Sheep sheep = new Sheep("tom", 1, "白色");
sheep.freend = new Sheep("小友", 16, "白色");
Sheep sheep2 = (Sheep) sheep.clone(); //克隆
Sheep sheep3 = (Sheep) sheep.clone(); //克隆
Sheep sheep4 = (Sheep) sheep.clone(); //克隆
Sheep sheep5 = (Sheep) sheep.clone(); //克隆
System.out.println(sheep == sheep2);
System.out.println(sheep.equals(sheep2));
System.out.println(sheep + "" + sheep.hashCode()+"spfr:"+sheep.freend.hashCode());
System.out.println(sheep2 + "" + sheep2.hashCode()+"spfr2:"+sheep2.freend.hashCode());
System.out.println(sheep3 + "" + sheep3.hashCode());
System.out.println(sheep4);
System.out.println(sheep5);
}
}
输出结果
复制后friend hashcode指向同一个地址，并没有进行复制，以上属于浅拷贝，非基本数据类型的对象不会进行复制而是指向地址
深拷贝，解决浅拷贝存在问题，会对非基本类型属性进行拷贝。实现方式两种1.重写clone方法 2.使用序列化来实现深拷贝
代码演示两种拷贝方式
package com.hy.prototype.deepclone;
import java.io.Serializable;
/**
* @author hanyong
* @date 2020/11/7 9:24
*/
public class DeepCloneableTarget implements Serializable, Cloneable {
private static final long serialVersionUID = 1L;
private String cloneName;
private String cloneClass;
//构造器
public DeepCloneableTarget(String cloneName, String cloneClass) {
this.cloneName = cloneName;
this.cloneClass = cloneClass;
}
@Override
protected Object clone() throws CloneNotSupportedException {
return super.clone();
}
}
package com.hy.prototype.deepclone;
import java.io.*;
/**
* @author hanyong
* @date 2020/11/7 9:27
*/
public class DeepProtoType implements Serializable, Cloneable {
public String name; //String 属性
public DeepCloneableTarget deepCloneableTarget;// 引用类型
public DeepProtoType() {
super();
}
//深拷贝 - 方式 1 使用clone 方法
@Override
protected Object clone() throws CloneNotSupportedException {
Object deep = null;
deep = super.clone();
DeepProtoType deepProtoType = (DeepProtoType) deep;
deepProtoType.deepCloneableTarget = (DeepCloneableTarget) deepCloneableTarget.clone();
return deepProtoType;
}
//深拷贝 - 方式2 通过对象的序列化实现 (推荐)
public Object deepClone() {
ByteArrayOutputStream bos = null;
ObjectOutputStream oos = null;
ByteArrayInputStream bis = null;
ObjectInputStream ois = null;
try {
//序列化
bos = new ByteArrayOutputStream();
oos = new ObjectOutputStream(bos);
oos.writeObject(this);
//反序列化
bis = new ByteArrayInputStream(bos.toByteArray());
ois = new ObjectInputStream(bis);
DeepProtoType copyObj = (DeepProtoType) ois.readObject();
return copyObj;
} catch (Exception e) {
e.printStackTrace();
return null;
} finally {
//关闭流
try {
bos.close();
oos.close();
bis.close();
ois.close();
} catch (Exception e2) {
// TODO: handle exception
System.out.println(e2.getMessage());
}
}
}
}
package com.hy.prototype.deepclone;
/**
* @author hanyong
* @date 2020/11/7 9:33
*/
public class Client {
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
DeepProtoType p = new DeepProtoType();
p.name = "宋江";
p.deepCloneableTarget = new DeepCloneableTarget("大牛", "小牛");
//方式1 完成深拷贝
// DeepProtoType p2 = (DeepProtoType) p.clone();
//
/*System.out.println("p.name=" + p.name + "p.deepCloneableTarget=" + p.deepCloneableTarget.hashCode());
System.out.println("p2.name=" + p2.name + "p2.deepCloneableTarget=" + p2.deepCloneableTarget.hashCode());*/
//方式2 完成深拷贝
DeepProtoType p2 = (DeepProtoType) p.deepClone();
System.out.println("p.name=" + p.name + "p.deepCloneableTarget=" + p.deepCloneableTarget.hashCode());
System.out.println("p2.name=" + p2.name + "p2.deepCloneableTarget=" + p2.deepCloneableTarget.hashCode());
}
}
测试结果