一、原型模式介紹

二、原型模式引入

需求：

傳統方式UML類圖：

程式碼實現(Java)：

public class Sheep {
    private String name;
    private int age;
    private String color;

    public Sheep(String name, int age, String color) {
        this.name = name;
        this.age = age;
        this.color = color;
    }

    public String getName() {
        
 
return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        
 
this.color = color;
    }

    @Override
    public String toString() {
        return "Sheep{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", color='" + color + '\'' +
                '}';
    }
}

public class Client {
    public static void main(String[] args) {
        
 
//傳統方法
        Sheep sheep = new Sheep("tom", 1, "白色");
        Sheep sheep1 = new Sheep(sheep.getName(), sheep.getAge(), sheep.getColor());
        Sheep sheep2 = new Sheep(sheep.getName(), sheep.getAge(), sheep.getColor());
        Sheep sheep3 = new Sheep(sheep.getName(), sheep.getAge(), sheep.getColor());
        Sheep sheep4 = new Sheep(sheep.getName(), sheep.getAge(), sheep.getColor());
        Sheep sheep5 = new Sheep(sheep.getName(), sheep.getAge(), sheep.getColor());

        System.out.println(sheep);
        System.out.println(sheep1);
        System.out.println(sheep2);
        System.out.println(sheep3);
        System.out.println(sheep4);
        System.out.println(sheep5);
    }
}

原型模式UML類圖：

原型模式(淺拷貝Java實現)：

public class Sheep implements Cloneable{
    private String name;
    private int age;
    private String color;
    private String address = "蒙古羊";
    public Sheep friend; //是物件，克隆會如何處理

    public Sheep(String name, int age, String color) {
        this.name = name;
        this.age = age;
        this.color = color;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    @Override
    public String toString() {
        return "Sheep{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", color='" + color + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    //克隆該例項，使用預設的clone方法來完成
    @Override
    protected Object clone() {
        Sheep sheep = null;
        try {
            sheep = (Sheep)super.clone();
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
        return sheep;
    }
}

public class Client {
    public static void main(String[] args) {
        System.out.println("原型模式完成物件的建立");
        Sheep sheep = new Sheep("tom", 1, "白色");

        sheep.friend = new Sheep("jack", 2, "黑色");

        Sheep sheep1 = (Sheep) sheep.clone();
        Sheep sheep2 = (Sheep) sheep.clone();
        Sheep sheep3 = (Sheep) sheep.clone();
        Sheep sheep4 = (Sheep) sheep.clone();

        System.out.println("sheep1 = "+sheep1 + "sheep1.friend="+sheep1.friend.hashCode());
        System.out.println("sheep2 = "+sheep2 + "sheep2.friend="+sheep2.friend.hashCode());
        System.out.println("sheep3 = "+sheep3 + "sheep3.friend="+sheep3.friend.hashCode());
        System.out.println("sheep4 = "+sheep4 + "sheep4.friend="+sheep4.friend.hashCode());
    }
}

原型模式(深拷貝Java實現)：

import java.io.Serializable;

public class DeepCloneableTarget implements Serializable, Cloneable {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    private String cloneName;

    private String cloneClass;

    //構造器
    public DeepCloneableTarget(String cloneName, String cloneClass) {
        this.cloneName = cloneName;
        this.cloneClass = cloneClass;
    }

    //因為該類的屬性，都是String , 因此我們這裡使用預設的clone完成即可
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

import java.io.*;

public class DeepProtoType implements Serializable, Cloneable{

    public String name; //String 屬性
    public DeepCloneableTarget deepCloneableTarget;// 引用型別
    public DeepProtoType() {
        super();
    }


    //深拷貝 - 方式 1 使用clone 方法
    @Override
    protected Object clone() throws CloneNotSupportedException {

        Object deep = null;
        //這裡完成對基本資料型別(屬性)和String的克隆
        deep = super.clone();
        //對引用型別的屬性，進行單獨處理
        DeepProtoType deepProtoType = (DeepProtoType)deep;
        deepProtoType.deepCloneableTarget  = (DeepCloneableTarget)deepCloneableTarget.clone();

        return deepProtoType;
    }

    //深拷貝 - 方式2 通過物件的序列化實現 (推薦)
    public Object deepClone() {

        //建立流物件
        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); //當前這個物件以物件流的方式輸出

            //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 {
            //關閉流
            try {
                bos.close();
                oos.close();
                bis.close();
                ois.close();
            } catch (Exception e2) {
                System.out.println(e2.getMessage());
            }
        }

    }

}

public class Client {

    public static void main(String[] args) throws Exception {
        DeepProtoType p = new DeepProtoType();
        p.name = "宋江";
        p.deepCloneableTarget = new DeepCloneableTarget("大牛", "小牛");

        //方式1 完成深拷貝

//        DeepProtoType p2 = (DeepProtoType) p.clone();
//
//        System.out.println("p.name=" + p.name + "p.deepCloneableTarget=" + p.deepCloneableTarget.hashCode());
//        System.out.println("p2.name=" + p.name + "p2.deepCloneableTarget=" + p2.deepCloneableTarget.hashCode());

        //方式2 完成深拷貝
        DeepProtoType p2 = (DeepProtoType) p.deepClone();

        System.out.println("p.name=" + p.name + "p.deepCloneableTarget=" + p.deepCloneableTarget.hashCode());
        System.out.println("p2.name=" + p.name + "p2.deepCloneableTarget=" + p2.deepCloneableTarget.hashCode());

    }

}

三、原型模式在Spring框架中原始碼分析

四、深入討論-淺拷貝和深拷貝

五、原型模式的注意事項和細節