下面是我的项目类Foo的简短代码：

public class Foo {
    @Autowired
    protected Mapper mapper;

    protected User getUser() {
        // ...
        return user;
    }
}

类Bar扩展Foo：

public class Bar extends Foo{

    public void func(String param1, String param2) {
        Result result = this.validateParams(param1, param2);
        // ...
        Entity entity = super.mapper.mapTo(param1, Entity.class);
        entity.setUserInfo(super.getUser().getInfo()); // null pointer exception
    }


    private Result validateParams(String param1, String param2) {
        // ...
        return Result.success();
    }
}

测试类：

@RunWith(PowerMockRunner.class)
@PowerMockIgnore( {"javax.management.*", "javax.net.ssl.*"})
@PrepareForTest({Bar.class}) // to mock private method
public class BarTest {
    @InjectMocks
    Bar bar;

    @Mock
    Mapper mapper;

    @Test
    public void testFunc() {
        bar = PowerMockito.spy(bar);
        bar.mapper = mapper; // or bar.mapper is null

        PowerMockito.doReturn(Result.success()).when(bar, validateParams, any(), any()); // mock private method

        User user = new User(); // mock user
        PowerMockito.doReturn(user).when(bar).getUser(); // doesn't work

        bar.func("param1", "param2");
    }
}

奇怪的是，当我测试bar.func时，当涉及到entity.setUserInfo(super.getUser().getInfo())时，super.getUser()返回null，导致NPE。但是我已经模拟了getUser（）函数，它似乎不起作用。期待您的建议和帮助，非常感谢。
我试图避免使用spy（bar），假设它会导致示例的空副本（全部为null）。我还试着用

Method methodGetUser = PowerMockito.method(Bar.class, "getUser");
    PowerMockito.replace(methodGetUser).with(new InvocationHandler() {
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            return user;
        }
    });

但不起作用（NPE）。