背景

最近，在使用springboot开发一个接口的时候，需要根据接收的请求事件类型，去执行不同的操作，返回不同的结果，基本逻辑如下：

String event = crsRequest.getEvent(); CRSResponse crsResponse = null; switch (event) { case CRSRequestEvent.APP_START: crsResponse = processAppStartCommand(crsRequest); break; case CRSRequestEvent.INIT_COMPLETE: crsResponse = processInitCompleteCommand(crsRequest); break; case CRSRequestEvent.COLLECT_COMPLETE: crsResponse = processCollectCompleteCommand(crsRequest); break; case CRSRequestEvent.COLLECT_NO_INPUT: crsResponse = processCollectNoInputCommand(crsRequest); break; case CRSRequestEvent.PLAY_COMPLETE: crsResponse = processPlayCompleteCommand(crsRequest); break; default: }

写完会发现，随着事件的增加，这段代码会很长，每个事件的处理函数也都集中在一个类当中，不好维护。因此，通过搜索学习发现，可以使用Springboot的注解+策略模式+简单工厂的方式来消除switch-case。

重构

定义结构体

public enum CRSEvent { APP_START("APP_START"), INIT_COMPLETE("INIT_COMPLETE"), PLAY_COMPLETE("PLAY_COMPLETE"), COLLECT_COMPLETE("COLLECT_COMPLETE"), COLLECT_NO_INPUT("COLLECT_NO_INPUT"), APP_END("APP_END"), RESP_ERROR_CMD("RESP_ERROR_CMD"); private String event; CRSEvent(String event){ this.event = event; } public String getEvent() { return event; } public void setEvent(String event) { this.event = event; }}

定义一个注解

@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)public @interface CRSEventAnnotation { CRSEvent value();}

定义事件处理接口

public interface EventProcess { CRSResponse execute(CRSRequest resquest);}

所有的时间处理类都要实现这个接口。其中，execute是事件的处理方法

编写具体的时间处理类

接下来，逐个的编写事件处理类，举下面一个例子：

@Component("appStartProcess")@CRSEventAnnotation(value = CRSEvent.APP_START)public class AppStartProcess implements EventProcess{ @Override public CRSResponse execute(CRSRequest resquest) { CRSResponse response = new CRSResponse(); response.setCommand(CRSResponseCmd.IVR_SESSION_INIT); CRSResponse.Message message = new CRSResponse.Message(); message.setTts_vid("65580"); message.setTts_speed("120"); response.setMessage(message); return response; }}

定义SpringContext工具类

@Componentpublic class SpringContextUtil implements ApplicationContextAware{ private ApplicationContext context; public ApplicationContext getContext(){ return context; } @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { this.context = applicationContext; }}

定义事件处理类工厂，用来生产各种事件处理对象

@Componentpublic class EventProcessFactory { @Autowired SpringContextUtil contextUtil; private static Map<CRSEvent, EventProcess> eventProcessMap = new ConcurrentHashMap<>(); public EventProcessFactory() { Map<String, Object> beanMap = contextUtil.getContext().getBeansWithAnnotation(CRSEventAnnotation.class); for (Object evetProcess : beanMap.values()) { CRSEventAnnotation annotation = evetProcess.getClass().getAnnotation(CRSEventAnnotation.class); eventProcessMap.put(annotation.value(), (EventProcess) evetProcess); } } public static EventProcess createEventProcess(CRSEvent event){ return eventProcessMap.get(event); }}

调用代码修改

CRSEvent crsEvent = CRSEvent.valueOf(crsRequest.getEvent()); EventProcess eventProcess = EventProcessFactory.createEventProcess(crsEvent); if (eventProcess != null){ return eventProcess.execute(crsRequest); }return null;

这样，代码就没有了switch-case，增加一个事件也很简单，只需要实现EventProcess接口即可。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。