原型模式

1.创建对象的方式有哪些？

a.new b。clone c。反序列化 d 反射

2.本节就考虑clone创建对象，原型模式简单来说就是利用clone创建对象，好处是，不用调用构造函数的的，clone是本地方法，速度很快，对于大对象创建的效率很棒。

 1 package 原型模式;
 2 
 3 import java.util.ArrayList;
 4 
 5 class Student implements Cloneable
 6 {
 7      int id;
 8     String name;
 9      ArrayList arry;
10     public Student(int id,String name,ArrayList arry)
11     {
12         this.id=id;
13         this.name=name;
14         this.arry=arry;
15         
16     }
17     public Student clone() throws CloneNotSupportedException
18     {
19     Student s= (Student) super.clone();
20     //  s.name=(String)this.name.clone();
21     //   s.arry=(ArrayList<Integer>) this.arry.clone();
22        return s;
23       
24       
25     
26         
27     }
28     }
29 
30 public class Pro {
31     public static void main(String args[]) throws CloneNotSupportedException
32     {
33         ArrayList<Integer> arr=new ArrayList<Integer>();
34         arr.add(99);//语文
35         arr.add(100);//数学
36      Student  s=new Student(1,"hansong",arr);
37      Student s2=s.clone();
38      s2.arry.add(45);
39      System.out.println(s.arry);// 是多少呢？ 结果是 99,100,45
40     
41     
42         
43         
44         
45         
46         
47     }
48 
49 }

3.深度拷贝

 1 package 原型模式;
 2 
 3 import java.util.ArrayList;
 4 
 5 class Student implements Cloneable
 6 {
 7      int id;
 8     String name;
 9      ArrayList arry;
10     public Student(int id,String name,ArrayList arry)
11     {
12         this.id=id;
13         this.name=name;
14         this.arry=arry;
15         
16     }
17     public Student clone() throws CloneNotSupportedException
18     {
19     Student s= (Student) super.clone();
20     //  s.name=(String)this.name.clone();
21      s.arry=(ArrayList<Integer>) this.arry.clone();
22        return s;
23       
24       
25     
26         
27     }
28     }
29 
30 public class Pro {
31     public static void main(String args[]) throws CloneNotSupportedException
32     {
33         ArrayList<Integer> arr=new ArrayList<Integer>();
34         arr.add(99);//语文
35         arr.add(100);//数学
36      Student  s=new Student(1,"hansong",arr);
37      Student s2=s.clone();
38      s2.arry.add(45);
39      System.out.println(s.arry);// 是多少呢？ 结果是 99,100,
40      System.out.println(s2.arry);//99.100,45
41     
42     
43         
44         
45         
46         
47         
48     }
49 
50 }

4.list中存放对象的浅拷贝

 1 package 原型模式;
 2 
 3 import java.util.ArrayList;
 4 class A
 5 {
 6     int x;
 7     public A(int y)
 8     {
 9         x=y;
10     }
11     }
12 
13 class Student implements Cloneable
14 {
15      int id;
16     String name;
17      ArrayList arry;
18     public Student(int id,String name,ArrayList arry)
19     {
20         this.id=id;
21         this.name=name;
22         this.arry=arry;
23         
24     }
25     public Student clone() throws CloneNotSupportedException
26     {
27     Student s= (Student) super.clone();
28     //  s.name=(String)this.name.clone();
29      s.arry=(ArrayList<A>) this.arry.clone();
30        return s;
31       
32       
33     
34         
35     }
36     }
37 
38 public class Pro {
39     public static void main(String args[]) throws CloneNotSupportedException
40     {
41         ArrayList<A> arr=new ArrayList<A>();
42         arr.add(new A(1));//语文
43         arr.add(new A(2));//数学
44      Student  s=new Student(1,"hansong",arr);
45      Student s2=s.clone();
46      s2.arry.add(new A(-3));
47      System.out.println(s.arry);// 是多少呢？ 结果是 99,100,
48      System.out.println(s2.arry);//99.100,45
49     
50     
51         
52         
53         
54         
55         
56     }
57 
58 }

View Code

5存放对象的深度拷贝

 1 package 原型模式;
 2 
 3 import java.util.ArrayList;
 4 class A implements Cloneable
 5 {
 6     int x;
 7     public A(int y)
 8     {
 9         x=y;
10     }
11     public A clone() throws CloneNotSupportedException
12     {
13         return (A) super.clone();
14     }
15     }
16 
17 class Student implements Cloneable
18 {
19      int id;
20     String name;
21      ArrayList arry;
22     public Student(int id,String name,ArrayList arry)
23     {
24         this.id=id;
25         this.name=name;
26         this.arry=arry;
27         
28     }
29     @SuppressWarnings("unchecked")
30     public Student clone() throws CloneNotSupportedException
31     {
32     Student s= (Student) super.clone();
33     //  s.name=(String)this.name.clone();
34      s.arry=(ArrayList<A>) this.arry.clone();
35        for(int i=0;i<s.arry.size();i++)
36        {
37            A a=(A) s.arry.get(i);
38            s.arry.set(i,a.clone());
39        }
40       
41       
42     return s;
43         
44     }
45     }
46 
47 public class Pro {
48     public static void main(String args[]) throws CloneNotSupportedException
49     {
50         ArrayList<A> arr=new ArrayList<A>();
51         arr.add(new A(1));//语文
52         arr.add(new A(2));//数学
53      Student  s=new Student(1,"hansong",arr);
54      Student s2=s.clone();
55      s2.arry.add(new A(-3));
56      System.out.println(s.arry);
57      System.out.println(s2.arry);
58     
59     
60         
61         
62         
63         
64         
65     }
66 
67 }

View Code

[原型模式.A@1fb8ee3, 原型模式.A@61de33]
[原型模式.A@14318bb, 原型模式.A@ca0b6, 原型模式.A@10b30a7]