[嘲笑QueryBuilder时为NullPointerException

Posted 2021-05-03

问题：

我正在尝试使用Mockito创建测试。此测试将模拟QueryBuilder，并尝试验证是否一切正常。但是我得到了[[“ java.lang.NullPointerException”。似乎尚未初始化，但是我看不到它是什么。

代码：

@RunWith(MockitoJUnitRunner.StrictStubs.class) public class AcademicJPADAOTest { @Mock private EntityManager entityManager; @Mock private CriteriaBuilder cb; @Mock private CriteriaQuery<Academic> cq; @Mock private Root<Academic> root; @InjectMocks AcademicJPADAO academicjpadao; private String passwdcode = "83997689-22b6-4a7e-a801"; @Test public void retrieveByPasswordCodeTest() throws PersistentObjectNotFoundException, MultiplePersistentObjectsFoundException { Academic academic = new Academic(); when(entityManager.getCriteriaBuilder()).thenReturn(cb); when(cb.createQuery(Academic.class)).thenReturn(cq); when(cq.from(Academic.class)).thenReturn(root); when(cq.where(cb.equal(root.get(Academic_.passwordCode), passwdcode))).thenReturn(cq); when(academicjpadao.getEntityManager().createQuery(cq).getSingleResult()).thenReturn(academic); academicjpadao.retrieveByPasswordCode(passwdcode); verify(entityManager, times(1)).getCriteriaBuilder(); } }

行错误：

when(academicjpadao.getEntityManager().createQuery(cq).getSingleResult()).thenReturn(academic);

答案

也许您的academicjpadao在此部分中未正确注入：

@InjectMocks AcademicJPADAO academicjpadao;

因此，请使用MockitoAnnotations.initMocks来启动@Mock和@InjectMocks对象。因此，您必须将此方法添加到类中：
@Before
public void setup() {
    MockitoAnnotations.initMocks(this);
}