spring注解

@Component("userManager")
public class UserManagerImpl implements UserManager {
private UserDao userDao ;
         public UserDao getUserDao() {
  return userDao;
}
@Resource    
public void setUserDao(UserDao userDao) {
  this.userDao = userDao;
}
  /* (non-Javadoc)
   * @see com.wjs.registration.service.UserManager#exists(com.wjs.registration.model.Users)
   */
  public boolean exists(Users u){
         return userDao.checkUserExistsWithName(u.getUsername());
   }
   /* (non-Javadoc)
   * @see com.wjs.registration.service.UserManager#add(com.wjs.registration.model.Users)
   */
    public void add(Users u){
         userDao.save(u);
    }
}
spring在持久层、业务层和控制层分别采用@Repository、@Service和@Controller 对分层中的类进行注释，而用@Component对那些比较中立的类进行注释
这里就是说把这个类交给Spring管理，重新起个名字叫userManager，由于不好说这个类属于哪个层面，就用@Component