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大话设计模式_原型模式(Java代码)

2024-07-07 08:48:34   230人阅读

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

简单描述：即通过实现接口Cloneable重写方法clone()，使得创建新的拷贝对象不需要一个成员一个成员的重新复制，而且可以提高创建对象的效率

Java中要想实现拷贝使用clone()方法，类必须实现Cloneable接口，并且重写Object类中的clone()方法，调用父类的clone()方法即可实现浅复制

代码如下：

WorkExperience类：

 1 package com.longsheng.prototype;
 2 
 3 public class WorkExperience {
 4 
 5     private String workDate;
 6     private String workCompany;
 7 
 8     public WorkExperience(String workDate, String workCompany) {
 9         this.workDate = workDate;
10         this.workCompany = workCompany;
11     }
12     
13     public String getWorkDate() {
14         return workDate;
15     }
16 
17     public void setWorkDate(String workDate) {
18         this.workDate = workDate;
19     }
20 
21     public String getWorkCompany() {
22         return workCompany;
23     }
24 
25     public void setWorkCompany(String workCompany) {
26         this.workCompany = workCompany;
27     }
28 
29 }

Resume类：

 1 package com.longsheng.prototype;
 2 
 3 public class Resume implements Cloneable {
 4 
 5     private String name;
 6     private String age;
 7     private String sex;
 8     private WorkExperience mWorkExperience;
 9 
10     public Resume( String name ) {
11         this.name = name;
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 String getAge() {
23         return age;
24     }
25 
26     public void setAge(String age) {
27         this.age = age;
28     }
29 
30     public String getSex() {
31         return sex;
32     }
33 
34     public void setSex(String sex) {
35         this.sex = sex;
36     }
37 
38     public WorkExperience getmWorkExperience() {
39         return mWorkExperience;
40     }
41 
42     public void setmWorkExperience(WorkExperience mWorkExperience) {
43         this.mWorkExperience = mWorkExperience;
44     }
45     
46     public void display() {
47         System.out.println(name + "   "  + sex + "   " + age);
48         System.out.println(mWorkExperience.getWorkDate() + "   " + mWorkExperience.getWorkCompany());
49     }
50     
51     protected Object clone() throws CloneNotSupportedException {
52         return super.clone();
53     }
54 
55 }

客户端：

 1 package com.longsheng.prototype;
 2 
 3 public class Client {
 4 
 5     public static void main(String[] args) throws Exception {
 6         Resume resumeA = new Resume("同学");
 7         resumeA.setAge("25");
 8         resumeA.setSex("男");
 9         WorkExperience mWorkExperience = new WorkExperience("2011-2014", "XX公司");
10         resumeA.setmWorkExperience(mWorkExperience);
11         Resume resumeB = (Resume)resumeA.clone();
12         mWorkExperience.setWorkCompany("YY公司");
13         resumeA.display();
14         resumeB.display();
15     }
16 
17 }

运行后得出结果：

1 同学 男 25
2 2011-2014 YY公司
3 同学 男 25
4 2011-2014 YY公司

由此可知super.clone()实现的是浅复制。

 

要想实现深复制，则可修改程序如下：

WorkExperience类(红色部分为修改的部分)：

 1 package com.longsheng.prototype;
 2 
 3 public class WorkExperience implements Cloneable {
 4 
 5     private String workDate;
 6     private String workCompany;
 7 
 8     public WorkExperience(String workDate, String workCompany) {
 9         this.workDate = workDate;
10         this.workCompany = workCompany;
11     }
12     
13     public String getWorkDate() {
14         return workDate;
15     }
16 
17     public void setWorkDate(String workDate) {
18         this.workDate = workDate;
19     }
20 
21     public String getWorkCompany() {
22         return workCompany;
23     }
24 
25     public void setWorkCompany(String workCompany) {
26         this.workCompany = workCompany;
27     }
28 
29     @Override
30     protected Object clone() throws CloneNotSupportedException {
31         return super.clone();
32     }
33     
34 }

Resume类(红色部分为修改的部分)：

 1 package com.longsheng.prototype;
 2 
 3 public class Resume implements Cloneable {
 4 
 5     private String name;
 6     private String age;
 7     private String sex;
 8     private WorkExperience mWorkExperience;
 9 
10     public Resume( String name ) {
11         this.name = name;
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 String getAge() {
23         return age;
24     }
25 
26     public void setAge(String age) {
27         this.age = age;
28     }
29 
30     public String getSex() {
31         return sex;
32     }
33 
34     public void setSex(String sex) {
35         this.sex = sex;
36     }
37 
38     public WorkExperience getmWorkExperience() {
39         return mWorkExperience;
40     }
41 
42     public void setmWorkExperience(WorkExperience mWorkExperience) {
43         this.mWorkExperience = mWorkExperience;
44     }
45     
46     public void display() {
47         System.out.println(name + "   "  + sex + "   " + age);
48         System.out.println(mWorkExperience.getWorkDate() + "   " + mWorkExperience.getWorkCompany());
49     }
50     
51     protected Object clone() throws CloneNotSupportedException {
52         Resume mResume = (Resume)super.clone();
53         mResume.setmWorkExperience((WorkExperience)this.getmWorkExperience().clone());
54         return mResume;
55     }//或者可以和书本类似，创建一个接收WorkExperience对象的构造器，在这个方法中先构造新对象，再设相应值，然后返回此新对象(如以下折叠的部分)
56 
57 }

另外一种实现方法(Resume类)

 1 package com.longsheng.prototype;
 2 
 3 public class Resume implements Cloneable {
 4 
 5     private String name;
 6     private String age;
 7     private String sex;
 8     private WorkExperience mWorkExperience;
 9 
10     public Resume( String name ) {
11         this.name = name;
12     }
13     
14     public Resume( WorkExperience mWorkExperience ) throws Exception {
15         this.mWorkExperience = (WorkExperience)mWorkExperience.clone();
16     }
17     
18     public String getName() {
19         return name;
20     }
21 
22     public void setName(String name) {
23         this.name = name;
24     }
25 
26     public String getAge() {
27         return age;
28     }
29 
30     public void setAge(String age) {
31         this.age = age;
32     }
33 
34     public String getSex() {
35         return sex;
36     }
37 
38     public void setSex(String sex) {
39         this.sex = sex;
40     }
41 
42     public WorkExperience getmWorkExperience() {
43         return mWorkExperience;
44     }
45 
46     public void setmWorkExperience(WorkExperience mWorkExperience) {
47         this.mWorkExperience = mWorkExperience;
48     }
49     
50     public void display() {
51         System.out.println(name + "   "  + sex + "   " + age);
52         System.out.println(mWorkExperience.getWorkDate() + "   " + mWorkExperience.getWorkCompany());
53     }
54     
55     protected Object clone() throws CloneNotSupportedException {
56         Resume mResume = null;
57         try {
58             mResume = new Resume(this.mWorkExperience);
59             mResume.setName(this.getName());
60             mResume.setAge(this.getAge());
61             mResume.setSex(this.getSex());
62         } catch (Exception e) {
63             e.printStackTrace();
64         }
65         return mResume;
66     }
67 
68 }
Resume

 

客户端代码不变，运行后的结果：

1 同学   男   25
2 2011-2014   YY公司
3 同学   男   25
4 2011-2014   XX公司

 


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