guice用@Before绑定以后还是报空指针

public class OrserTest {
    @Inject private OrderServer orderServer;

    @Before private void setUp(){
        Guice.createInjector(new ServerModule()).injectMembers(this);
    }
    @Test
    public void testSendToPayment(){
        orderServer.sendToOrderPaid(789L);
    }
}