原型模式（Prototype Pattern）：
用一个已经创建的实例作为原型，通过复制该原型对象来创建一个和原型相同或相似的新对象。
原型模式的核心就是拷贝（复制）对象， 拷贝对象分为：浅拷贝（浅复制）和深拷贝（深复制）；浅拷贝：只拷贝对象中的基本数据类型（8种），对于数组、容器、引用对象等都不会拷贝；深拷贝：不仅能拷贝基本数据类型，还要拷贝数组、容器、引用对象等；
原型模式的角色：
抽象原型类（Prototype）、具体原型类（Concrete Prototype）和访问类（Client）；
java 实现原型模式的方法是：克隆（Object类中的clone()方法）、通过对象 序列化 以及反序列化；
原型模式的应用场景
1、类初始化需要消化非常多的资源，这个资源包括：数据、硬件资源等，通过原型拷贝避免这些消耗。
2、通过new一个对象需要非常繁琐的数据准备或访问权限，可以使用原型模式。
3、一个对象需要提供给其他对象访问，而且各个调用者可能需要修改其值，可以考虑使用原型模式拷贝多个对象供调用者使用，即保护性拷贝。
原型模式的代码案例
1、浅拷贝实现
/**
* java.lang.Cloneable为抽象原型类（Prototype）
* Person为具体原型类
*/public class Person implements Cloneable{
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ Override
protected Object clone() throws CloneNotSupportedException {
return super.clone();
}
}
/**
* 访问类（Client）
*/public class PrototypePattern {
public static void main(String[] args) {
// 浅拷贝实现
Person person = new Person();
person.setId(1024);
person.setName("唐僧");
Person person2 = null;
try {
person2 = (Person) person.clone();
System.out.println(person2.getId() + "," + person2.getName());
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
System.out.println(person == person2);
System.out.println("person hashCode -> " + person.hashCode());
System.out.println("person2 hashCode -> " + person2.hashCode());
System.out.println(person.equals(person2));
}
} 2、深拷贝实现，通过实现java.lang.Cloneable接口
/**
* java.lang.Cloneable为抽象原型类（Prototype）
* Person为具体原型类
*/public class Person implements Cloneable{
private int id;
private String name;
private IDCard idCard;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public IDCard getIdCard() {
return idCard;
}
public void setIdCard(IDCard idCard) {
this.idCard = idCard;
}
@Override
protected Object clone() throws CloneNotSupportedException {
Person person = null;
try {
person = (Person)super.clone();
IDCard cloneIDCard = (IDCard)idCard.clone();
person.setIdCard(cloneIDCard);
}catch(Exception e) {
}
return person;
}
}
/**
* java.lang.Cloneable为抽象原型类（Prototype）
* IDCard为具体原型类
*/public class IDCard implements Cloneable {
// 号码
private String number ;
// 过期时间
private String expiryTime;
public String getExpiryTime() {
return expiryTime;
}
public String getNumber() {
return number;
}
public void setExpiryTime(String expiryTime) {
this.expiryTime = expiryTime;
}
public void setNumber(String number) {
this.number = number;
}
@Override
protected Object clone() throws CloneNotSupportedException {
return super.clone();
}
}
/**
* 访问类（Client）
*/public class PrototypePattern {
public static void main(String[] args) {
// 深拷贝实现
IDCard idCard = new IDCard();
idCard.setNumber("2020XXXXXXXXXXXXXXXXXXXXXXX");
idCard.setExpiryTime("20200720");
Person person = new Person();
person.setId(1024);
person.setName("唐僧");
person.setIdCard(idCard);
Person person2 = null;
try {
person2 = (Person) person.clone();
System.out.println(person2.getId() + "," + person2.getName());
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
System.out.println("person==person2 => " + (person == person2));
System.out.println("person hashCode => " + person.hashCode());
System.out.println("person2 hashCode => " + person2.hashCode());
System.out.println("person equals person2 => " + person.equals(person2));
System.out.println("IdCard==IdCard2 => " + (person.getIdCard() == person2.getIdCard()));
System.out.println("person IdCard hashCode -> " + person.getIdCard().hashCode());
System.out.println("person2 IdCard hashCode -> " + person2.getIdCard().hashCode());
System.out.println("IdCard equals IdCard2 => " + person.getIdCard().equals(person2.getIdCard()));
}
} 3、深拷贝实现，通过序列化和反序列化实现
/**
* 抽象原型类（Prototype）
*/public interface AbstractPrototype {
public Person cloneObject();
}
public class Person implements java.io.Serializable,AbstractPrototype {
private static final long serialVersionUID = 29082744664639018L;
private int id;
private String name;
private IDCard idCard;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public IDCard getIdCard() {
return idCard;
}
public void setIdCard(IDCard idCard) {
this.idCard = idCard;
}
public Person cloneObject(){
Person person = null;
try {
// 序列化操作
ByteArrayOutputStream byteOuput = new ByteArrayOutputStream();
ObjectOutputStream objectOuput = new ObjectOutputStream(byteOuput);
objectOuput.writeObject(this);
// 反序列化（字节数组缓冲区）
ByteArrayInputStream byteInput = new ByteArrayInputStream(byteOuput.toByteArray());
ObjectInputStream objectInput = new ObjectInputStream(byteInput);
person = (Person)objectInput.readObject();
objectInput. close ();
byteInput.close();
byteOuput.close();
objectOuput.close();
} catch (Exception e) {
e.printStackTrace();
}
return person;
}
}
public class IDCard implements java.io.Serializable {
private static final long serialVersionUID = -2351753423118799929L;
// 号码
private String number;
// 过期时间
private String expiryTime;
public String getExpiryTime() {
return expiryTime;
}
public String getNumber() {
return number;
}
public void setExpiryTime(String expiryTime) {
this.expiryTime = expiryTime;
}
public void setNumber(String number) {
this.number = number;
}
}
/**
* 访问类（Client）
*/public class PrototypePattern {
public static void main(String[] args) {
// 深拷贝实现
IDCard idCard = new IDCard();
idCard.setNumber("2020XXXXXXXXXXXXXXXXXXXXXXX");
idCard.setExpiryTime("20200720");
Person person = new Person();
person.setId(1024);
person.setName("唐僧");
person.setIdCard(idCard);
Person person2 = null;
try {
person2 = (Person) person.cloneObject();
System.out.println(person2.getId() + "," + person2.getName());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("person==person2 => " + (person == person2));
System.out.println("person hashCode => " + person.hashCode());
System.out.println("person2 hashCode => " + person2.hashCode());
System.out.println("person equals person2 => " + person.equals(person2));
System.out.println("IdCard==IdCard2 => " + (person.getIdCard() == person2.getIdCard()));
System.out.println("person IdCard hashCode -> " + person.getIdCard().hashCode());
System.out.println("person2 IdCard hashCode -> " + person2.getIdCard().hashCode());
System.out.println("IdCard equals IdCard2 => " + person.getIdCard().equals(person2.getIdCard()));
}
} 
