1.开闭原则(OCP)
遵循开闭原则设计出的模块具有两个主要特征：
（1）对于扩展是开放的（Open for extension）。这意味着模块的行为是可以扩展的。当应用的需求改变时，我们可以对模块进行扩展，使其具有满足那些改变的新行为。也就是说，我们可以改变模块的功能。
（2）对于修改是关闭的（Closed for modification）。对模块行为进行扩展时，不必改动模块的源代码或者二进制代码。模块的二进制可执行版本，无论是可链接的库、DLL或者.EXE文件，都无需改动。
2.通过UML认识OCP
3.代码
(1)IShoe接口
1 package com.alibaba.www.miao;
2
3 public interface IShoe {
4
5 public String getName();
6 public String getType();
7 public int getValue();
8 }
(2)MenShoe实现IShoe接口
1 package com.alibaba.www.miao;
2
3 public class MenShoe implements IShoe {
4
5 private String name;
6 private String type;
7 private int value;
8
9 public MenShoe(String name, String type, int value) {
10 super();
11 this.name = name;
12 this.type = type;
13 this.value = value;
14 }
15
16 @Override
17 public String getName() {
18 return this.name;
19 }
20
21 @Override
22 public String getType() {
23 return this.type;
24 }
25
26 @Override
27 public int getValue() {
28 return this.value;
29 }
30
31 }
(3)GirlShoe实现IShoe接口
1 package com.alibaba.www.miao;
2
3 public class GirlShoe implements IShoe {
4
5 private String name;
6 private String type;
7 private int value;
8
9 public GirlShoe(String name, String type, int value) {
10 super();
11 this.name = name;
12 this.type = type;
13 this.value = value;
14 }
15
16 @Override
17 public String getName() {
18 return this.name;
19 }
20
21 @Override
22 public String getType() {
23 return this.type;
24 }
25
26 @Override
27 public int getValue() {
28 return this.value;
29 }
30
31 }
(4)PriceCutMenShoe继承MenShoe类
1 package com.alibaba.www.miao;
2
3 public class PriceCutMenShoe extends MenShoe {
4
5 public PriceCutMenShoe(String name, String type, int value) {
6 super(name, type, value);
7 }
8
9 public int getValue() {
10 int primeCost = super.getValue();
11 int cutPrice = 0;
12 if (primeCost > 200) {
13 cutPrice = cutPrice * 80 / 100;
14 }
15 if (primeCost > 150) {
16 cutPrice = cutPrice * 85 / 100;
17 }
18 return cutPrice;
19 }
20 }
(5)PriceCutGirlShoe继承GirlShoe类
1 package com.alibaba.www.miao;
2
3 public class PriceCutGirlShoe extends GirlShoe {
4
5 public PriceCutGirlShoe(String name, String type, int value) {
6 super(name, type, value);
7 }
8
9 public int getValue() {
10 int primeCost = super.getValue();
11 int cutPrice = 0;
12 if (primeCost > 200) {
13 cutPrice = cutPrice * 75 / 100;
14 System.out.println("如果原价大于200元，则打折7.5折");
15 }
16 if (primeCost > 150) {
17 cutPrice = cutPrice * 80 / 100;
18 System.out.println("如果原价大于150元，则打折8折");
19 } else {
20 cutPrice = cutPrice * 85 / 100;
21 System.out.println("其他。则打8.5折");
22 }
23 return primeCost;
24 }
25 }
(6)测试ocp.jsp，验证开闭原则
1 <%@page import="com.alibaba.www.miao.PriceCutGirlShoe"%>
2 <%@ page language="java" contentType="text/html; charset=UTF-8"
3 pageEncoding="UTF-8"%>
4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5 <html>
6 <head>
7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
8 <title>Insert title here</title>
9 </head>
10 <body>
11
12 <%
13 PriceCutGirlShoe a = new PriceCutGirlShoe("女鞋名","女鞋类型",160);
14 out.print("鞋价为:"+a.getValue());
15 %>
16
17 </body>
18 </html>
(7)参考目录结构
源码下载:http://download.csdn.net/detail/sxmiaochuang/7629901
Java Web 设计模式之开闭原则,布布扣,bubuko.com
时间： 2024-12-29 16:22:00