原型模式

一、定义：

​ 原型模式，用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。

二、特点：

​ 一般在初始化信息不发生变化的情况下，克隆是最好的方法。这既隐藏了对象创建的细节，又对性能是大大的提高。可以不用重新初始化对象，而是动态地获得对象运行时的状态。

浅复制：只复制它本身和其中包含的值的类型的成员变量，而引用类型的成员变量并没有被复制。所有的对其他对象的引用仍然指向原来的对象。

深复制：复制它本身和其中包含的所有成员变量。

三、示例代码：

​ 浅复制：

//原型类，简历
public class Resume implements Cloneable {
    private String name;
    private String sex;
    private String age;
    private WorkExperience work;

    public void setPersonalInfo(String sex, String age) {
        this.sex = sex;
        this.age = age;
    }

    public Resume(String name) {
        this.name = name;
        work = new WorkExperience();
    }

    public void setWork(String workDate, String workCompany) {
        work.setWorkCompany(workCompany);
        work.setWorkDate(workDate);
    }

    public void display() {
        System.out.println("name:"+name+" age:"+age+" sex:"+sex);
        System.out.println("workExperience:"+work.getWorkCompany()+" "+work.getWorkDate());
    }
    
    public Resume clone(){
        Object object=null;
        try {
          object = super.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();

        }
        return (Resume) object;
    }
}

//引用对象,工作经历类
public class WorkExperience {
    private String workDate;
    private String workCompany;

    public String getWorkDate() {
        return workDate;
    }

    public void setWorkDate(String workDate) {
        this.workDate = workDate;
    }

    public String getWorkCompany() {
        return workCompany;
    }

    public void setWorkCompany(String workCompany) {
        this.workCompany = workCompany;
    }
}

//客户端类
public class Client {
    public static void main(String[] args) {
        Resume resume = new Resume("小鹏");
        resume.setPersonalInfo("male", "20");
        resume.setWork("2017-2018", "tencent");

        Resume resume1 = resume.clone();
        Resume resume2 = resume.clone();
        //一个对象的引用类型发生变化，三个对象都发生了变化。值类型不变
        resume1.setWork("23", "2334");
        resume1.setPersonalInfo("23", "2334");


        resume.display();
        resume1.display();
        resume2.display();
    }
}

深复制：

//原型类
public class Resume implements Cloneable {
    private String name;
    private String sex;
    private String age;
    private WorkExperience work;

    public void setPersonalInfo(String sex, String age) {
        this.sex = sex;
        this.age = age;
    }

    public Resume(String name) {
        this.name = name;
        work = new WorkExperience();
    }

    public void setWork(String workDate, String workCompany) {
        work.setWorkCompany(workCompany);
        work.setWorkDate(workDate);
    }

    public void display() {
        System.out.println("name:" + name + " age:" + age + " sex:" + sex);
        System.out.println("workExperience:" + work.getWorkCompany() + " " + work.getWorkDate());
    }

    public Resume clone() {
        Object object = null;
        try {
            object = super.clone();
            //引用类型和对象本身都需要克隆
            Resume resume = (Resume) object;
            resume.work = work.clone();
            return (Resume) object;
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
            return null;
        }
    }
}

//工作经历类，引用类也需要实现cloneable接口
public class WorkExperience implements Cloneable {
    private String workDate;
    private String workCompany;

    public String getWorkDate() {
        return workDate;
    }

    public void setWorkDate(String workDate) {
        this.workDate = workDate;
    }

    public String getWorkCompany() {
        return workCompany;
    }

    public void setWorkCompany(String workCompany) {
        this.workCompany = workCompany;
    }
    public WorkExperience clone(){
        Object  object=null;
        try {
            object=super.clone();
            return (WorkExperience) object;
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
            return null;
        }
    }
}

//客户端
public class Client {
    public static void main(String[] args) {
        Resume resume = new Resume("小鹏");
        resume.setPersonalInfo("male", "20");
        resume.setWork("2017-2018", "tencent");
		//深复制把引用对象的变量指向复制过的新对象，而不是原有的被引用的对象
        Resume resume1 = resume.clone();
        Resume resume2 = resume.clone();
        resume1.setWork("23", "2334");
        resume1.setPersonalInfo("23", "2334");


        resume.display();
        resume1.display();
        resume2.display();
    }
}