工具类中如何注入Dao层Bean

@Component
public class UserRequest {

	@Autowired
	private SysUserDao sysUserDao;

	private static UserRequest UserRequest;

	@PostConstruct
	public void init() {
		UserRequest = this;
		UserRequest.sysUserDao = this.sysUserDao;
	}

	public static String getCurrentToken() {
		HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
				.getRequest();
		String token = request.getHeader("token");
		return token;
	}

	public static SysUserEntity getCurrentUser() {
		String token = getCurrentToken();
		UserRequest.sysUserDao.selectById(null);
		return null;
	}

}