java - Mockito 在 createCriteria 中测试 DAO 得到 NullPointerException

Question

我正在尝试为 dao 层编写测试。我在 hibernate 状态下工作，当我尝试测试我的方法 getAll 时，我在 createCriteria 行中收到异常 NullPointerException ，我不知道如何解决问题。

这是我的异常(exception):

java.lang.NullPointerException
    at dao.UserDaoTest.testFindAll(UserDaoTest.java:69)

这是我的测试类(class):

@Mock
private SessionFactory sessionFactory;
@Mock
private Session session;
@Mock
private Transaction transaction;
@InjectMocks
private UserDaoImpl userDao;

private User user;

@Before
public void setUpUser(){
    user = new User();
    user.setName("is name");
    when(sessionFactory.openSession()).thenReturn(session);
    when(session.beginTransaction()).thenReturn(transaction);
}
@Test
public void testFindAll(){
    List<User> userList = new ArrayList<>();
    userList.add(user);
    when(session.createCriteria(User.class).list()).thenReturn(userList); //NullPointerException
    List<User> userList1 = userDao.findAll();
    assertThat(userList1, is(userList));
}

这是 Dao 类:

private Session session;
private Transaction transaction;
public List<User> findAll() {
    List<User> userList = null;
    session = sessionFactory.openSession();
    transaction = null;
    try{
        transaction = session.beginTransaction();
        userList = session.createCriteria(User.class).list();
        transaction.commit();
    }catch (HibernateException e) {
        if (transaction!=null) {
            transaction.rollback();
        }
        e.printStackTrace();
    }finally {
        session.close();
    }
    return userList;
}

Answer 1

在 testFindAll() 中尝试类似的操作

Criteria aCriteria = Mockito.mock(Criteria.class);
when(session.createCriteria(User.class)).thenReturn(aCriteria);
when(aCriteria.list()).thenReturn(userList);