原型模式

骑猪看日落 2021-09-17 01:08 289阅读 0赞

原型模式：用原型实例指定创建指定对象的种类，并且通过复制这些原型创建新的对象，同时又能保证性能。这种模式是实现了一个原型接口，该接口用于创建当前对象的克隆。当直接创建对象的代价比较大时，则采用这种模式。

注意：如果字段是值类型的，则对该字段执行逐位复制，如果字段是引用类型，则复制引用但是不复制引用的对象，因此，原始对象及其复本引用同一对象。

潜复制：被复制对象的所有变量都含有原来的对象相同的值，而所有的对其他对象的引用仍然指向原来的对象。

深复制：把引用对象的变量指向复制过来的新对象，而不是原有的被引用的对象；

潜复制实例UML图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmdfc2h1eXU_size_16_color_FFFFFF_t_70][]

深复制实例UML图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmdfc2h1eXU_size_16_color_FFFFFF_t_70 1][]

潜复制代码：

/**
     * @author Shuyu.Wang
     * @package:com.shuyu.prototype
     * @description:
     * @date 2018-11-16 23:11
     **/
    @Data
    public class WorkExperience {
        private String workDate;
        private String company;
    }
    
    
    
    
    
    /**
     * @author Shuyu.Wang
     * @package:com.shuyu.prototype
     * @description:原型类,实现Cloneable，重写clone(),实现浅复制
     * @date 2018-11-16 23:05
     **/
    @Slf4j
    public class Resume implements Cloneable{
        private String name;
        private String sex;
        private String age;
        private WorkExperience workExperience;
        public Resume(String name){
            this.name=name;
            workExperience=new WorkExperience();
        }
    
        public void setPersonInfo(String sex,String age){
            this.sex=sex;
            this.age=age;
        }
    
        public void setWorkExperience(String workDate,String company){
            workExperience.setWorkDate(workDate);
            workExperience.setCompany(company);
        }
    
        public void show(){
            log.info("name="+name,",sex="+sex,",age="+age);
            log.info("company="+workExperience.getCompany(),"workDate="+workExperience.getWorkDate());
        }
    
        @Override
        public Object clone() {
            Object clone = null;
            try {
                clone = super.clone();
            } catch (CloneNotSupportedException e) {
                e.printStackTrace();
            }
            return clone;
        }
    
    }

深复制代码：

/**
     * @author Shuyu.Wang
     * @package:com.shuyu.prototype
     * @description:
     * @date 2018-11-16 23:11
     **/
    @Data
    public class WorkExperience2 implements Cloneable{
        private String workDate;
        private String company;
    
        @Override
        public Object clone() {
            Object clone = null;
            try {
                clone = super.clone();
            } catch (CloneNotSupportedException e) {
                e.printStackTrace();
            }
            return clone;
        }
    }
    
    
    
    
    
    
    
    
    
    /**
     * @author Shuyu.Wang
     * @package:com.shuyu.prototype
     * @description:原型类,实现Cloneable，重写clone(),实现深复制
     * @date 2018-11-16 23:05
     **/
    @Slf4j
    public class Resume2 implements Cloneable{
        private String name;
        private String sex;
        private String age;
        private WorkExperience2 workExperience;
        public Resume2(String name){
            this.name=name;
            workExperience=new WorkExperience2();
        }
    
        public void setPersonInfo(String sex,String age){
            this.sex=sex;
            this.age=age;
        }
    
        public void setWorkExperience(String workDate,String company){
            workExperience.setWorkDate(workDate);
            workExperience.setCompany(company);
        }
    
        public void show(){
            log.info("name="+name,",sex="+sex,",age="+age);
            log.info("company="+workExperience.getCompany(),"workDate="+workExperience.getWorkDate());
        }
    
        @Override
        public Object clone() {
            Resume2 clone = null;
            try {
                clone = (Resume2)super.clone();
                clone.workExperience=(WorkExperience2) workExperience.clone();
            } catch (CloneNotSupportedException e) {
                e.printStackTrace();
            }
            return clone;
        }
    
    }

测试代码：

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class PrototypeApplicationTests {
    
    	@Test
    	public void clone1() {
    		Resume resume=new Resume("测试1");
    		resume.setPersonInfo("男","25");
    		resume.setWorkExperience("2016-2017","台达");
    
    		Resume resume1=(Resume)resume.clone();
    		resume1.setWorkExperience("2017-2018","百度");
    
    		Resume resume2=(Resume)resume.clone();
    		resume2.setWorkExperience("2018-2019","阿里");
    		resume.show();
    		resume1.show();
    		resume2.show();
    
    	}
    
    
    	@Test
    	public void clone2() {
    		Resume2 resume=new Resume2("测试1");
    		resume.setPersonInfo("男","25");
    		resume.setWorkExperience("2016-2017","台达");
    
    		Resume2 resume1=(Resume2)resume.clone();
    		resume1.setWorkExperience("2017-2018","百度");
    
    		Resume2 resume2=(Resume2)resume.clone();
    		resume2.setWorkExperience("2018-2019","阿里");
    
    		resume.show();
    		resume1.show();
    		resume2.show();
    	}
    
    }

运行结果如下：

2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : name=测试1  
2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : company=阿里  
2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : name=测试1  
2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : company=阿里  
2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : name=测试1  
2018-11-16 23:40:51.859  INFO 44132 --- \[           main\] com.shuyu.prototype.Resume               : company=阿里

代码github地址：[https://github.com/iot-wangshuyu/designpatterns/tree/master/prototype][https_github.com_iot-wangshuyu_designpatterns_tree_master_prototype]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmdfc2h1eXU_size_16_color_FFFFFF_t_70]: /images/20210901/31fef48decb64e759b4dfc4f2ccf6119.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmdfc2h1eXU_size_16_color_FFFFFF_t_70 1]: /images/20210901/e8969293359f4e31acae996ca8baf70a.png
[https_github.com_iot-wangshuyu_designpatterns_tree_master_prototype]: https://github.com/iot-wangshuyu/designpatterns/tree/master/prototype