优雅的构造器模式 

 1 public class A {
 2 
 3     private int a;
 4 
 5     private int b;
 6 
 7     private int c;
 8 
 9 
10 
11     public int getA() {
12         return a;
13     }
14     public int getB() {
15         return b;
16     }
17     public int getC() {
18         return c;
19     }
20     public static class Builder {
21 
22         private int a;
23 
24         private int b;
25 
26         private int c;
27 
28         public Builder(){}
29 
30         public Builder seta(int a) { this.a = a; return this;} 
31 
32         public Builder setb(int b) { this.b = b; return this;}
33 
34         public Builder setc(int c) { this.c = c; return this;}
35 
36         public A build() { return new A(this);}
37 
38     }
39 
40 
41 
42     private A(Builder builder) {
43 
44         this.a = builder.a;
45 
46         this.b = builder.b;
47 
48         this.c = builder.c;
49 
50     }
51     public static void main(String[] args) {
52         A a = new A.Builder().seta(0).setb(1).setc(2).build();
53         System.out.println(a.getA()+a.getB()+a.getC());
54     }
55 
56 }

输出 ：  3

posted @ 2018-01-18 09:39  勤劳的杯子  阅读(131)  评论(0)  编辑  收藏  举报