spring Strategy 策略模式

spring容器注入实现策略模式

spring容器注入实现策略模式

Posted by John Doe on 2022-04-22
Words 908 and Reading Time 4 Minutes
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背景

一个项目对接多个系统的同一功能，或者同一功能多种实现的选择需求的策略模式实现。

Spring容器实现

需求: 物质采购汉堡选择，可以选择采购肯德基或麦当劳

示例代码:

汉堡策略类上下文HamburgerContext:

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@Component
public class HamburgerContext {

    /**
     * 汉堡采购service的实现类
     */
    @Autowired
    private final Map<String, HamburgerStrategy> HamburgerStrategyMap = new ConcurrentHashMap<>();

    /**
     *
     * HamburgerStrategyContext
     * @author guozhixian
     * @date 2022-4-14
     */
    public HamburgerStrategy getHamburgerStrategy(String key) {
        return HamburgerStrategyMap.get(key);
    }
}

汉堡策略类接口HamburgerStrategy：

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/**
 * HamburgerStrategy
 * @date 2022-4-14
 */
public interface HamburgerStrategy {

    String getBeefBurger(String count);

    String getChickenBurger(String count);
}

汉堡策略接口实现类KFCStrategy：

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@Service("KFCStrategy")
@Slf4j
public class KFCStrategy implements HamburgerStrategy{
    
    @Override
    public String getBeefBurger(String count) {
        log.info("采购KFC牛肉汉堡{}个",count);
        return String.format("KFC牛肉汉堡%s个", count);
    }
    
    @Override
    public String getChickenBurger(String count) {
        log.info("采购KFC鸡肉汉堡{}个",count);
        return String.format("KFC鸡肉汉堡%s个", count);
    }
}

汉堡策略接口实现类McDonaldStrategy：

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@Service("McDonaldStrategy")
public class McDonaldStrategy implements HamburgerStrategy{
    
    @Override
    public String getBeefBurger(String count) {
        log.info("采购麦当劳牛肉汉堡{}个",count);
        return String.format("麦当劳牛肉汉堡%s个", count);
    }
    
    @Override
    public String getChickenBurger(String count) {
        log.info("采购麦当劳鸡肉汉堡{}个",count);
        return String.format("麦当劳鸡肉汉堡%s个", count);
    }
}

实现类枚举HamburgerEnum

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@Getter
@AllArgsConstructor
public enum HamburgerEnum {
     /**
     * KFC实现类
     */
    KFC("1", "KFCStrategy"),

    /**
     * McDonald实现类
     */
    MCDONALD("2", "McDonaldStrategy");
     /**
     * 单值码
     */
    private final String code;

    /**
     * 值
     */
    private final String value;
    
    public static String getStrategyByCode(String code) {
        // 默认KFC实现类
        String result = HamburgerEnum.KFC.value;
        for (HamburgerEnum hamburgerEnum : HamburgerEnum.values()) {
            if (StringUtils.equals(HamburgerEnum.code, code)) {
                result = HamburgerEnum.value;
                break;
            }
        }
        return result;
    }    
}

controller调用的策略选择service

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@Service
public class HamburgerChooseStrategy {
    
    @Autowired
    private HamburgerContext hamburgerContext;
    
    @Value("${type}")
    private String type;
    
    
     /**
     * 根据配置选择哪家牛肉汉堡
     * @param count 数量
	 * @return String
     */
    public String getBeefBurgerBySysConfig(String count) {
        return hamburgerContext.getHamburgerStrategy(HamburgerEnum.getStrategyByCode(type)).getBeefBurger(count);
    }
    
    
     /**
     * 根据参数选择哪家鸡肉汉堡
     */
     public String getChickenBurgerByParam(String count, String code) {
        return hamburgerContext.getHamburgerService(HamburgerEnum.getStrategyByCode(code)).getChickenBurger(count);
    }
}

传统策略模式写法实现

汉堡策略类上下文HamburgerContext:

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public class HamburgerContext {

    private final HamburgerStrategy hamburgerStrategy
        
    public HamburgerContext(HamburgerStrategy hamburgerStrategy) {
        this.hamburgerStrategy = hamburgerStrategy;
    }        

	public String getBeefBurger(String count) {
        this.hamburgerStrategy.getBeefBurger(count);
    }

    public String getChickenBurger(String count) {
        this.hamburgerStrategy.getChickenBurger(count);
    }
}

汉堡策略类接口HamburgerStrategy：

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/**
 * HamburgerStrategy
 * @date 2022-4-14
 */
public interface HamburgerStrategy {

    String getBeefBurger(String count);

    String getChickenBurger(String count);
}

汉堡策略接口实现类KFCStrategy：

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@Service
@Slf4j
public class KFCStrategy implements HamburgerStrategy{
    
    @Override
    public String getBeefBurger(String count) {
        log.info("采购KFC牛肉汉堡{}个",count);
        return String.format("KFC牛肉汉堡%s个", count);
    }
    
    @Override
    public String getChickenBurger(String count) {
        log.info("采购KFC鸡肉汉堡{}个",count);
        return String.format("KFC鸡肉汉堡%s个", count);
    }
}

汉堡策略接口实现类McDonaldStrategy：

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@Service
public class McDonaldStrategy implements HamburgerStrategy{
    
    @Override
    public String getBeefBurger(String count) {
        log.info("采购麦当劳牛肉汉堡{}个",count);
        return String.format("麦当劳牛肉汉堡%s个", count);
    }
    
    @Override
    public String getChickenBurger(String count) {
        log.info("采购麦当劳鸡肉汉堡{}个",count);
        return String.format("麦当劳鸡肉汉堡%s个", count);
    }
}

实现类枚举HamburgerEnum

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@Getter
@AllArgsConstructor
public enum HamburgerEnum {
     /**
     * KFC实现类
     */
    KFC("1", "KFC"),

    /**
     * McDonald实现类
     */
    MCDONALD("2", "MCDONALD");
     /**
     * 单值码
     */
    private final String code;

    /**
     * 值
     */
    private final String name;
}

controller调用的策略选择service

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@Service
public class HamburgerChooseStrategy {
    
    @Value("${type}")
    private String type;
    
    @Autowired
    private KFCStrategy kfcStrategy;
    
    @Autowired
    private McDonaldStrategy mcDonaldStrategy;
    
    @PostConstruct
    private void init() {
        HamburgerStrategy hamburgerStrategy;
        if (StringUtils.isNotBlank(type) && HamburgerEnum.KFC.getName().equals(type)) {
            hamburgerStrategy = kfcStrategy;
        }else {
            hamburgerStrategy = mcDonaldStrategy;
        }
        HamburgerContext = new HamburgerContext(hamburgerStrategy);
    }

    
     /**
     * 根据配置选择哪家牛肉汉堡
     * @param count 数量
	 * @return String
     */
    public String getBeefBurgerBySysConfig(String count) {
        return hamburgerContext.getBeefBurger(count);
    }
    
    
     /**
     * 根据参数选择哪家鸡肉汉堡
     */
     public String getChickenBurgerByParam(String count, String code) {
        return hamburgerContext.geChickenBurger(count);
    }
}

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