原型模式

Posted 2021-02-01 linbq1911

1.定义：指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；
　　　　不需要知道任何创建的细节，不调用构造函数

2.类型：创建型

3.适用场景：类初始化消耗较多资源；new产生的一个对象需要非常繁琐的过程(数据准备、访问权限等)；
　　　　构造函数比较复杂；循环体中产生大量对象时。

4.优点：原型模式性能比直接new一个对象性能高；简化创建过程。

5.缺点：必须配备克隆方法；对克隆复杂对象或对克隆出的对象进行复杂改造时，容易引入风险；
　　　　深拷贝、浅拷贝要运用得当。

6.扩展：深克隆；浅克隆。

7.实例目录package

8.实例UML类图

9.代码

 1 package com.geely.design.pattern.creational.prototype;
 2 
 3 public class Mail implements Cloneable{
 4     private String name;
 5     private String emailAddress;
 6     private String content;
 7     public Mail(){
 8         System.out.println("Mail Class Constructor");
 9     }
10 
11     public String getName() {
12         return name;
13     }
14 
15     public void setName(String name) {
16         this.name = name;
17     }
18 
19     public String getEmailAddress() {
20         return emailAddress;
21     }
22 
23     public void setEmailAddress(String emailAddress) {
24         this.emailAddress = emailAddress;
25     }
26 
27     public String getContent() {
28         return content;
29     }
30 
31     public void setContent(String content) {
32         this.content = content;
33     }
34 
35     @Override
36     public String toString() {
37         return "Mail{" +
38                 "name=‘" + name + ‘‘‘ +
39                 ", emailAddress=‘" + emailAddress + ‘‘‘ +
40                 ", content=‘" + content + ‘‘‘ +
41                 ‘}‘+super.toString();
42     }
43 
44     @Override
45     protected Object clone() throws CloneNotSupportedException {
46         System.out.println("clone mail object");
47         return super.clone();
48     }
49 }

 1 package com.geely.design.pattern.creational.prototype;
 2 
 3 import java.text.MessageFormat;
 4 
 5 public class MailUtil {
 6     public static void sendMail(Mail mail){
 7         String outputContent = "向{0}同学，邮件地址：{1},邮件内容：{2}发送邮件成功。";
 8         System.out.println(MessageFormat.format(outputContent,mail.getName(),mail.getEmailAddress(),mail.getContent()));
 9     }
10     public static void saveOriginMailRecord(Mail mail){
11         System.out.println("存储originMail记录,originMail:"+mail.getContent());
12     }
13 }

 1 package com.geely.design.pattern.creational.prototype;
 2 
 3 public class Test {
 4     public static void main(String[] args) throws CloneNotSupportedException {
 5         Mail mail = new Mail();
 6         mail.setContent("初始化模板");
 7         System.out.println("初始化mail:"+mail);
 8         for(int i = 0;i < 10; i++){
 9             Mail mailTemp =(Mail) mail.clone();
10             mailTemp.setName("姓名" + i);
11             mailTemp.setEmailAddress("姓名"+i+"@imooc.com");
12             mailTemp.setContent("恭喜你，此次慕课网活动中奖了");
13             MailUtil.sendMail(mailTemp);
14             System.out.println("克隆的mailTemp:"+mailTemp);
15         }
16         MailUtil.saveOriginMailRecord(mail);
17     }
18 }

1 package com.geely.design.pattern.creational.prototype.abstractprototype;
2 
3 public abstract class A implements Cloneable{
4     @Override
5     protected Object clone() throws CloneNotSupportedException {
6         return super.clone();
7     }
8 }

1 package com.geely.design.pattern.creational.prototype.abstractprototype;
2 
3 public class B extends A {
4     public static void main(String[] args) throws CloneNotSupportedException {
5         B b = new B();
6         b.clone();
7     }
8 }

 1 package com.geely.design.pattern.creational.prototype.clone;
 2 
 3 import java.util.Date;
 4 
 5 public class Pig implements Cloneable{
 6     private String name;
 7     private Date birthday;
 8 
 9     public Pig(String name, Date birthday) {
10         this.name = name;
11         this.birthday = birthday;
12     }
13 
14     public String getName() {
15         return name;
16     }
17 
18     public void setName(String name) {
19         this.name = name;
20     }
21 
22     public Date getBirthday() {
23         return birthday;
24     }
25 
26     public void setBirthday(Date birthday) {
27         this.birthday = birthday;
28     }
29 
30     @Override
31     protected Object clone() throws CloneNotSupportedException {
32         Pig pig = (Pig)super.clone();
33         pig.birthday = (Date)pig.birthday.clone();
34         return pig;
35     }
36 
37     @Override
38     public String toString() {
39         return "Pig{" +
40                 "name=‘" + name + ‘‘‘ +
41                 ", birthday=" + birthday +
42                 ‘}‘+ super.toString();
43     }
44 }

 1 package com.geely.design.pattern.creational.prototype.clone;
 2 
 3 import java.util.Date;
 4 
 5 public class Test {
 6     public static void main(String[] args) throws CloneNotSupportedException {
 7         Date birthday = new Date(0L);
 8         Pig pig1 = new Pig("佩奇", birthday);
 9         Pig pig2 = (Pig)pig1.clone();
10         System.out.println(pig1);
11         System.out.println(pig2);
12         System.out.println(pig1 == pig2);
13         pig1.getBirthday().setTime(66666666666666L);
14         System.out.println(pig1);
15         System.out.println(pig2);
16         System.out.println(pig1 == pig2);
17     }
18 }