1.使用doAnswer方法解决，代码如下：
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = {Application.class})
public class ControllerTest {
@Test
public void updateReading() throws Exception {
Answer<Object> answer = invocationOnMock -> invocationOnMock.getArguments();
doAnswer(answer).when(taskModificationService)
.changeReadingStatus(anyList(),anyByte());
}
} 2.上面的写法有点累赘，创建了Answer对象，又什么都没做，不如直接使用doNothing比较简单明了。
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = {Application.class})
public class ControllerTest {
@Test
public void updateReading() throws Exception {
doNothing().when(taskModificationService).changeReadingStatus(anyList(),anyByte());
}
} 其他方法请参考：https://yanbin.blog/mockito-how-to-mock-void-method/#more-7748