策略模式：定义算法家族，分别封装，让它们之间可以互相替换，此模式让算法的变化不会影响到使用算法的客户
简单描述：一个父类，多个子类实现具体方法。一个Context类持有父类的引用(使用子类实例化此引用)，客户端代码只需要与此Context类交互即可
大话设计模式中的截图：
例子代码：
策略类：
1 package com.longsheng.strategy;
2
3 public abstract class Strategy {
4
5 public abstract double getResult( double cash );
6
7 }
Strategy
促销满减类：
1 package com.longsheng.strategy;
2
3 public class CashReturn extends Strategy {
4
5 private double moneyCondition;
6 private double moneyReturn;
7
8 public CashReturn(double moneyCondition, double moneyReturn) {
9 super();
10 this.moneyCondition = moneyCondition;
11 this.moneyReturn = moneyReturn;
12 }
13
14 public double getMoneyCondition() {
15 return moneyCondition;
16 }
17
18 public void setMoneyCondition(double moneyCondition) {
19 this.moneyCondition = moneyCondition;
20 }
21
22 public double getMoneyReturn() {
23 return moneyReturn;
24 }
25
26 public void setMoneyReturn(double moneyReturn) {
27 this.moneyReturn = moneyReturn;
28 }
29
30 @Override
31 public double getResult(double cash) {
32 double result = cash;
33 if (cash >= moneyCondition) {
34 result = cash - (cash / moneyCondition) * moneyReturn;
35 }
36 return result;
37 }
38
39 }
CashReturn
促销折扣类：
1 package com.longsheng.strategy;
2
3 public class CashRebate extends Strategy {
4
5 private double discount;
6
7 public double getDiscount() {
8 return discount;
9 }
10
11 public void setDiscount(double discount) {
12 this.discount = discount;
13 }
14
15 public CashRebate(double discount) {
16 this.discount = discount;
17 }
18
19 @Override
20 public double getResult(double cash) {
21 return cash * getDiscount();
22 }
23
24 }
CashRebate
正常结算类：
1 package com.longsheng.strategy;
2
3 public class CashNormal extends Strategy {
4
5 @Override
6 public double getResult( double cash ) {
7 return cash;
8 }
9
10 }
CashNormal
策略Context:(与简单工厂相结合)
1 package com.longsheng.strategy;
2
3 public class StrategyContext {
4
5 private Strategy str;
6
7 /**
8 * a 代表正常收费; b 代表打7折; c 代表满500减100
9 * @param s
10 */
11 public StrategyContext(String s) {
12 switch (s) {
13 case "a":
14 this.str = new CashNormal();
15 break;
16 case "b":
17 this.str = new CashRebate(0.7d);
18 break;
19 case "c":
20 this.str = new CashReturn(500d, 100d);
21 break;
22 }
23 }
24
25 public double getResult(double cash) {
26 return str.getResult(cash);
27 }
28 }
StrategyContext
客户端：
1 package com.longsheng.strategy;
2
3 //商场促销，打折、满减、满送积分等
4 public class Client {
5
6 public static void main(String[] args) {
7 // a 代表正常收费; b 代表打7折; c 代表满500减100
8 double total = 1000d;
9
10 StrategyContext sa = new StrategyContext("a");
11 System.out.println(sa.getResult(total));
12
13 StrategyContext sb = new StrategyContext("b");
14 System.out.println(sb.getResult(total));
15
16 StrategyContext sc = new StrategyContext("c");
17 System.out.println(sc.getResult(total));
18 }
19
20 }
Client
在分析过程中听到需要在不同时间应用不同的业务规则，就可以考虑使用策略模式处理这种变化的可能性
大话设计模式_策略模式(Java代码),布布扣,bubuko.com
时间： 2024-10-12 13:21:29