案例：假如以快餐类为需求。模拟现实业务
方法一：简单工厂+策略模式（采用afterPropertiesSet方法）

			//从这里可以看出使用了大量il/else,如果是真实业务
			//可能每个if/else中又有大量的业务逻辑这样就会显得代码很臃肿
  		 String type="";
        if (type.equals("炒饭")) {
            System.out.println("10块钱");
        } else if (type.equals("炒米粉")) {
            System.out.println("12块钱");
        } else if (type.equals("炒火腿")) {
            System.out.println("14块钱");
        } else if (type.equals("炒粉")) {
            System.out.println("16块钱");
        }
    }

/**

 * @Author cgz
 * @Date 2022/11/18 9:30
 */
 //注意需要继承这个InitializingBean或者实现类实现这个InitializingBean才会自动注入Bean
 //策略模式定义策略
public interface Strategy extends InitializingBean{
		void getDecs()；
}
//这里要让这个bean被扫描到才会自动注册到工厂里
//如果需要afterPropertiesSet这个方法启动时久把该类存到内存中还需要加注解，不然spring默认是实例化该方法才会调用到
@Service
@Lazy(value=false)
public class StrategyA implements Strategy{
    @Override
    public String price(String type) {
        return "10";
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        StrategyFactory.register("炒饭",this);
    }
}

@Service
@Lazy(value=false)
public class StrategyB implements Strategy{
    @Override
    public String price(String type) {
        return "12";
    }


    @Override
    public void afterPropertiesSet() throws Exception {
        StrategyFactory.register("炒米粉",this);
    }
}
@Service
@Lazy(value=false)
public class StrategyC implements Strategy{
    @Override
    public String price(String type) {
        return "14";
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        StrategyFactory.register("炒火腿",this);

    }
}

@Service
@Lazy(value=false)
public class StrategyD implements Strategy{
    @Override
    public String price(String type) {
        return "16";
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        StrategyFactory.register("炒粉",this);
    }


}

策略工厂

@Component
public class StrategyFactory {
    @Autowired
    private static Map<String, Strategy> strategyMap = new HashMap<>();

    public static Strategy getInvokeStrategy(String username) {
        return strategyMap.get(username);
    }

    public static void register(String name, Strategy handler) {
        if (ObjectUtils.isEmpty(name) && handler == null) {
            return;
        }
        strategyMap.put(name, handler);
    }

}

方法二：

 * @Author cgz
 * @Date 2022/11/18 9:30
 */
public interface Strategy {
		String price()；
}

@Service
public class StrategyA implements Strategy{
    @Override
    public String price(String type) {
        return "10";
    }

   
}

@Service
public class StrategyB implements Strategy{
    @Override
    public String price(String type) {
        return "12";
    }


}
@Service
public class StrategyC implements Strategy{
    @Override
    public String price(String type) {
        return "14";
    }

   
}

@Service
public class StrategyD implements Strategy{
    @Override
    public String price(String type) {
        return "16";
    }




}

策略工厂

@Component
public class StrategyFactory {
   @Autowired
    private static Map<String, Strategy> strategyMap = new HashMap<>();

    public static Strategy getInvokeStrategy(String username) {
        return strategyMap.get(username);
    }

		//调用工厂得时候放入map
        static {
        strategyMap.put("炒饭", new StrategyA());
        strategyMap.put("炒米粉",new StrategyB());
        strategyMap.put("炒火腿",new StrategyC());
        strategyMap.put("炒粉",new StrategyD());

    }

}