Spring注入在不同的服务类中不起作用 [英] Spring Injection not working in different service class

问题描述

我有课

@Service("registrationService")
@Transactional
public class RegistrationService {

@Resource(name="registrationDAO")
 public RegistrationDAO registrationDAO;

在控制器中，我可以毫无问题地访问 registrationService 和 registrationDAO.

In the Controller i can access registrationService and registrationDAO with no problem.

我还有一堂课

@Service("securityService")
public class SecurityService implements UserDetailsService {

 protected static Logger logger = Logger.getLogger("service");

 @Resource(name="registrationDAO")
 public RegistrationDAO registrationDAO;


  public String test(){
        logger.debug(registrationDAO.findUserByID(1) );
    return "Testing";
  }

现在，如果我在控制器中调用测试函数，那么它会在 registrationDAO 上给出空指针异常

Now if i call test function in controller then it gives null pointer exception on registrationDAO

推荐答案

All your @Service, @Repository, @Controller, @Component(等)注解类必须由弹簧管理才能自动装配工作.确保它们被 spring 类路径扫描:

All your @Service, @Repository, @Controller, @Component (etc.) annotated class must be spring-managed for autowiring to work. Make sure they are picked up by spring classpath scanning:

<context:component-scan base-package="com.company" />

在某些情况下，@Autowire 按类型进行自动装配，可用于避免使用 @Resourcename 参数代码>.

In some cases @Autowire, which does autowiring by type, can be useful to avoid the name argument you're supplying with the @Resource.

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