原型模式

原型模式属于对象的创建模式。通过给出一个原型对象来指明所有创建的对象的类型，然后用复制这个原型对象的办法创建出更多同类型的对象。

原型模式又分为浅拷贝和深拷贝模式，类中只有简单数据类型的拷贝属于浅拷贝，如：

class Prototype 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;
    }
    
    public Object clone(){
        Prototype p = null;
        try {
            p = (Prototype) super.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return p;
    }
}

当类中持有其他类的对象的实例时，需要使用深拷贝，深拷贝又有两种方法，第一种是将持有的对象再分别进行浅拷贝，这种方法适合持有少量对象：

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;
    }
    
    public Object clone(){
        Person person = null;
        try{
            person = (Person) super.clone();
        }catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return person;
    }
}

class Prototype implements Cloneable{
    private boolean flag;
    private Person person;
    public boolean isFlag() {
        return flag;
    }
    public void setFlag(boolean flag) {
        this.flag = flag;
    }
    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }
    
    public Object clone(){
        Prototype p = null;
        try{
            p = (Prototype) super.clone();
            p.person = (Person) person.clone();
        }catch(CloneNotSupportedException e){
            e.printStackTrace();
        }
        return p;
    }
}

另一种深拷贝的方法就是使用序列化：

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

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;
    }
    
    public Object clone(){
        Person person = null;
        try{
            person = (Person) super.clone();
        }catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return person;
    }
}

class Prototype implements Serializable{
    private boolean flag;
    private Person person;
    public boolean isFlag() {
        return flag;
    }
    public void setFlag(boolean flag) {
        this.flag = flag;
    }
    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }
    
    public Object clone() {
        try{
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(oos);
            
            ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());  
            ObjectInputStream ois = new ObjectInputStream(bis);  
            return ois.readObject();
        }catch(IOException e){
            e.printStackTrace();
        }catch(ClassNotFoundException e){
            e.printStackTrace();
        }
        return null;
    }
}