设计模式: 一个简单的策略模式demo

在Springboot项目中使用策略模式实现加减乘除

参考链接：设计模式-策略者模式

• 定义一个策略接口IStrategy
• 多个IStrategy接口的实现类
• 策略处理类ExecuteContext
• 通过ExecuteContext获取bean去调用具体方法(入参是IStrategy接口的实现类)

定义一个接口IStrategy

public interface IStrategy<T> extends InitializingBean {

    int run(int num1, int num2);


    OperatorTypeEnum supportedOperatorType();

    @Override
    default void afterPropertiesSet() throws Exception {
        ExecuteContext.addExecuteStrategy(supportedOperatorType(), this);
    }
}

多个IStrategy接口的实现类

枚举

public enum OperatorTypeEnum {
    ADD,SUB,MUL,DIV;
}

@Component
public class AddStrategy implements IStrategy<AddStrategy>{


    @Override
    public int run(int num1, int num2) {
        return num1 + num2;
    }

    @Override
    public OperatorTypeEnum supportedOperatorType() {
        return OperatorTypeEnum.ADD;
    }
}

@Component
public class SubStrategy implements IStrategy<SubStrategy> {
    @Override
    public int run(int num1, int num2) {
        return num1 - num2;
    }

    @Override
    public OperatorTypeEnum supportedOperatorType() {
        return OperatorTypeEnum.SUB;
    }
}

@Component
public class MulStrategy implements IStrategy<MulStrategy> {
    @Override
    public int run(int num1, int num2) {
        return num1 * num2;
    }

    @Override
    public OperatorTypeEnum supportedOperatorType() {
        return OperatorTypeEnum.MUL;
    }
}

@Component
public class DivStrategy implements IStrategy<DivStrategy> {

    @Override
    public int run(int num1, int num2) {
        return num1 * num2;
    }

    @Override
    public OperatorTypeEnum supportedOperatorType() {
        return OperatorTypeEnum.DIV;
    }
}

策略处理类ExecuteContext

@Component
public class ExecuteContext {

    private static EnumMap<OperatorTypeEnum, IStrategy<?>> strategyMap  = new EnumMap<>(OperatorTypeEnum.class);


    public static void addExecuteStrategy(OperatorTypeEnum operatorType, IStrategy<?> strategy) {
        strategyMap.put(operatorType, strategy);
    }

    public static Integer executeStrategy(OperatorTypeEnum operatorType, int num1, int num2) {
        IStrategy<?> strategy = strategyMap.get(operatorType);
        if (strategy != null) {
            return strategy.run(num1, num2);
        }

        return null;
    }
}

controller实现

	@GetMapping("/demo/designTest")
    Integer designTest(@RequestParam(value = "operatorType") OperatorTypeEnum operatorType,
                       @RequestParam(value = "num1") int num1 ,
                       @RequestParam(value = "num2") int num2);

  
    @Override
    public Integer designTest(OperatorTypeEnum operatorType, int num1, int num2) {
        log.info("operatorType: {}, num1: {}, num2: {}", operatorType, num1, num2);
        Integer result = executeContext.executeStrategy(operatorType, num1, num2);
        log.info("result: {}", result);
        return result;
    }