如何根據用戶地區代碼注入服務類

我想從用戶地址中的區號獲取公交/公交車站信息打開api。如何根據用戶地區代碼注入服務類

區域是城市，城市提供彼此不同的巴士信息api。

TrafficController.java

@Controller 
public class TrafficController { 

    .... 
    @Autowired 
    public UserService userService; 

    public TrafficService trafficService; 
    .... 

    @RequestMapping(value="/api/traffic/stations") 
    public List<....> getNearStations(HttpServerletRequest req) { 
     String userId = SessionAttrs.getUserId(req.getSession()); 
     User user = userSerivce.getUser(userId); 

     trafficService = (TrafficService) Class.forName("com.myservice.service.impl.TrafficService_"+user.house.apt.address.area_code + "_Impl").newInstence(); 
     return trafficService.getStations(user.house.apt.latitude, user.house.apt.longitude, 300, 2); 

    } 
}

TrafficService_11_Impl.java

@Service 
public Class TrafficService_11_Impl implemnet TrafficService { 
    @Autowired 
    TrafficRepository trafficRepository; 

    @Override 
    public List<Station> getStations(double lat, double lng, int ratius, int retryCount) { 

     final String cacheKey = "getStations " + lat + " " + lng + " " + radius; 
     TrafficeCache cache = trafficRepository.fineOne(chcheKey); // run time NullPointerException, trafficRepository is null 

     if (null == cache) { 
      ... 
      get area code 11 api call logic 
      ... 
     } 

     ... 
     return ...; 
    } 
}

TrafficRepository.java

public interface TrafficRepository extends JpaRepository<TrafficCache, String> { 
}

該代碼發生運行時的NullPointerException在

TrafficService_11_Impl.java在

TrafficeCache緩存= trafficRepository.fineOne（chcheKey）;

運行時NullPointerException異常，trafficRepository爲null

Otherly在TrafficController.java

@Autowired 
public TrafficService trafficService

拖放代碼

trafficService = (TrafficService) Class.forName("com.myservice.service.impl.TrafficService_"+user.house.apt.address.area_code + "_Impl").newInstence();

是正確的結果

如何在String引導中根據用戶區號注入服務類？

來源

2015-11-20 basscraft

縮進代碼，添加更好的格式。問題仍然很少問 –

您是否打算爲*每個可能的區號創建一個單獨的'TrafficService'實現？無論你的「區號」是什麼，以及可能有多少，這都不是你應該怎麼做的。創建一個封裝區域代碼之間差異的'TrafficService'實現。 – kryger

[爲什麼我的Spring @Autowired字段爲空]？（http://stackoverflow.com/questions/19896870/why-is-my-spring-autowired-field-null） – chrylis

TrafficController.java

@Controller 
public class TrafficController { 

    .... 
    @Autowired 
    private ApplicationContext context; 

    @Autowired 
    public UserService userService; 

    public TrafficService trafficService; 
    .... 

    @RequestMapping(value="/api/traffic/stations") 
    public List<....> getNearStations(HttpServerletRequest req) { 
     String userId = SessionAttrs.getUserId(req.getSession()); 
     User user = userSerivce.getUser(userId); 

     trafficService = (TrafficService) context.getBean(Class.forName("com.myservice.service.impl.TrafficService_"+user.house.apt.address.area_code + "_Impl")); 
     return trafficService.getStations(user.house.apt.latitude, user.house.apt.longitude, 300, 2); 

    } 
}

這是正確的結果

來源

2015-11-23 02:11:00 basscraft

如何根據用戶地區代碼注入服務類

回答

相關問題