Springboot集成策略模式和工厂模式

2019-12-09

1.SpringBoot集成策略模式和工厂模式

1.1 SpringBoot结构图

1.2 编写接口（用于扩展）

1	public interface Strategy {
2	String doOperation();
3	}

1.3 编写实现类

@Service
@HandlerType(value = "1", zclass = Strategy.class) //该注解在本文后面定义
public class StrategyOne implements Strategy {
    @Override
    public String doOperation() {
        return "one";
    }
}

@Service
@HandlerType(value = "2", zclass = Strategy.class)//该注解在本文后面定义
public class StrategyTwo implements Strategy {
    @Override
    public String doOperation() {
        return "two";
    }
}

@Service
@HandlerType(value = "3", zclass = Strategy.class)//该注解在本文后面定义
public class StrategThree implements Strategy {
    @Override
    public String doOperation() {
        return "three";
    }
}

1.4 定义自定义注解

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface HandlerType {

    /**
     * 策略类型
     * @return
     */
    String value();

    /**
     * 接口class类
     * @return
     */
    Class<?> zclass();

}

1.5 定义处理器，用来处理标识的Service类

@Component
public class HandlerProcessor implements ApplicationContextAware {
    /**
     * 获取所有的策略Beanclass 加入HandlerOrderContext属性中
     *
     * @param applicationContext 上下文
     * @throws BeansException 没有实体的异常
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        //获取所有策略注解的Bean
        Map<String, Object> handlerMap = applicationContext.getBeansWithAnnotation(HandlerType.class);
        handlerMap.forEach((k, v) -> {
            // 获取对应的对象
            Class<?> handlerclass = v.getClass();
            // 注解中的type
            String type = handlerclass.getAnnotation(HandlerType.class).value();
            // 注解中的zclass
            Class<?> zclass = handlerclass.getAnnotation(HandlerType.class).zclass();
            //将class加入map中,type作为key
            Map<String, Class<?>> factoryMap = ConversionFactory.conversionFactoryMap.get(zclass);
            if (null == factoryMap) {
                factoryMap = new HashMap<>();
                factoryMap.put(type, handlerclass);
            }else {
                factoryMap.put(type, handlerclass);
            }
            ConversionFactory.conversionFactoryMap.put(zclass, factoryMap);
        });
    }
}

1.6 定义转换工厂

@Service
@Slf4j
public class ConversionFactory<T> {

    //存放所有策略类Bean的map
    public static Map<Class<?>, Map<String, Class<?>>> conversionFactoryMap = new ConcurrentHashMap<>();

    /**
     * 获取对应的类对象
     *
     * @param type           类型
     * @param interfaceClass 接口类反射
     * @return 返回一个类对象
     * @throws IllegalAccessException 没有访问权限
     * @throws InstantiationException 实例化异常
     */
    public T getResult(String type, Class<?> interfaceClass) throws IllegalAccessException, InstantiationException {
        // 打印在Map中的存在的数据
        log.debug("缓存中的数据，一共有 >>>>>>> {}", conversionFactoryMap.toString());
        // 获取接口归类
        Map<String, Class<?>> classMap = conversionFactoryMap.get(interfaceClass);
        // 获取对应的对象，并强转成自己的类
        Class<T> zclass = (Class<T>) classMap.get(type);
        if (zclass == null) {
            throw new IllegalArgumentException("没有对应的类型");
        }
        //从容器中获取对应的策略Bean
        log.info("转换后的类属性为 >>>> {}", zclass.newInstance());
        return zclass.newInstance();
    }

}

1.7 编写Controller（控制器）测试

@Controller
@Slf4j
public class StrategyController {

    /**
     * 传入想拿的service的名称后，sevice放回一个对应的service
     * @param key 想拿的service名称
     * @return
     */
    @GetMapping("/strategy")
    @ResponseBody
    public String strategy(@RequestParam("key") String key) {
        String result;
        try {
            ConversionFactory<Strategy> conversionFactory = new ConversionFactory<>();
            result = conversionFactory.getResult(key, Strategy.class).doOperation();
        } catch (Exception e) {
            e.printStackTrace();
            result = e.getMessage();
        }
        return result;
    }

}

注：pom文件

本文使用SpringBoot的版本为2.2.2.RELEASE

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>