SpringBoot切换不同的实现时，出现nullPointer问题

 

1，有时候算法需要迭代，相同的接口需要多个实现，自己可以随意切换，接口类：

package com.xxx.shortvideo.manager; public interface VideoRecommendedManger { FeedVideoByUserDTO getVideoByUser(FeedVideoByUserReq req); }

2, 针对接口有两个实现

3，通过配置config类来实现

package com.xxxx.shortvideo.config; import com.xxxx.shortvideo.enums.BizTypeEnum; import com.xxxx.shortvideo.manager.VideoRecommendedManger; import com.xxxx.shortvideo.manager.impl.VideoRecHotWordMangerImpl; import com.xxxx.shortvideo.manager.impl.VideoRecommendedMangerImpl; import com.google.common.collect.Maps; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import java.util.Map; @Configuration public class ShortVideoFillServiceConfig { @Autowired ApplicationContext applicationContext; @Bean Map<String, VideoRecommendedManger> shortVideoRecServiceMap() { Map<String, VideoRecommendedManger> shortVideoRecServiceMap = Maps.newHashMap(); shortVideoRecServiceMap.put(BizTypeEnum.SHORT_VIDEO_DEFAULT.getPrefix(), applicationContext.getBean(VideoRecommendedMangerImpl.class)); shortVideoRecServiceMap.put(BizTypeEnum.SHORT_VIDEO_HOT_WORD.getPrefix(), applicationContext.getBean(VideoRecHotWordMangerImpl.class)); return shortVideoRecServiceMap; } }

 

4,调用具体的实现

import javax.annotation.Resource; import java.util.Map; @RestController @RequestMapping("/facade/shortvideo") @Slf4j public class FeedVideoController { @Resource Map<String, VideoRecommendedManger> shortVideoRecServiceMap; //根据用户，获取video的list @RequestMapping(value = "/recommend", method = RequestMethod.POST) @PermissionCheck(skipAop=true) @ResponseBody public Res<FeedVideoByUserDTO> getVideoListByUserReq(@RequestBody FeedVideoByUserReq req) { try { FeedVideoByUserDTO videoByUser = null; if((BizTypeEnum.SHORT_VIDEO_HOT_WORD.getPrefix()).equals(req.getFlowTo())) { videoByUser = shortVideoRecServiceMap.get(BizTypeEnum.SHORT_VIDEO_HOT_WORD.getPrefix()).getVideoByUser(req); }else { videoByUser = shortVideoRecServiceMap.get(BizTypeEnum.SHORT_VIDEO_DEFAULT.getPrefix()).getVideoByUser(req); } log.info(String.format("用户推荐视频调用成功，返回：[%s]", JSON.toJSONString(videoByUser))); return Res.wrapSuccessfulResult(videoByUser); } catch (Exception e) { e.printStackTrace(); } return Res.wrapErrorResult(-1, "系统异常！"); } }

5，注意事项：

5.1 如果 Map<String, HotelRecommendedManger>  hotelRecServiceMap为String 类型：则需要 @Resource修饰

5.2如果 Map<Integer, HotelRecommendedManger>  hotelRecServiceMap为Integer类型：则需要 @Autowire修饰