使用注解的方式，实现对虚拟数据表 news(id(int),title(varcha(100)),author(varchar(50)),content(text),pubdate(date)) 进行操作的三层结构，写出测试程序

以下是使用注解的方式实现对虚拟数据表news进行操作的三层结构的代码：

1. 实体类News.java

@Table(name = "news")
public class News {
    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    private int id;
    private String title;
    private String author;
    private String content;
    private Date pubdate;

    // getter and setter methods
}

2. Dao层接口NewsDao.java

public interface NewsDao extends JpaRepository<News, Integer> {
}

3. Service层实现NewsServiceImpl.java

@Service
public class NewsServiceImpl implements NewsService {
    @Autowired
    private NewsDao newsDao;

    @Override
    public List<News> findAll() {
        return newsDao.findAll();
    }

    @Override
    public News findById(int id) {
        return newsDao.findById(id).orElse(null);
    }

    @Override
    public News save(News news) {
        return newsDao.save(news);
    }

    @Override
    public void delete(int id) {
        newsDao.deleteById(id);
    }
}

4. 控制层NewsController.java

@RestController
@RequestMapping("/news")
public class NewsController {
    @Autowired
    private NewsService newsService;

    @GetMapping("/")
    public List<News> findAll() {
        return newsService.findAll();
    }

    @GetMapping("/{id}")
    public News findById(@PathVariable int id) {
        return newsService.findById(id);
    }

    @PostMapping("/")
    public News save(@RequestBody News news) {
        return newsService.save(news);
    }

    @DeleteMapping("/{id}")
    public void delete(@PathVariable int id) {
        newsService.delete(id);
    }
}

5. 测试类NewsControllerTest.java

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
public class NewsControllerTest {
    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private NewsDao newsDao;

    @Test
    public void testFindAll() throws Exception {
        mockMvc.perform(get("/news/"))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$", hasSize(0)));

        News news = new News();
        news.setTitle("test title");
        news.setAuthor("test author");
        news.setContent("test content");
        news.setPubdate(new Date());
        newsDao.save(news);

        mockMvc.perform(get("/news/"))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$", hasSize(1)))
                .andExpect(jsonPath("$[0].title", is("test title")));
    }

    @Test
    public void testFindById() throws Exception {
        News news = new News();
        news.setTitle("test title");
        news.setAuthor("test author");
        news.setContent("test content");
        news.setPubdate(new Date());
        newsDao.save(news);

        mockMvc.perform(get("/news/" + news.getId()))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.title", is("test title")));
    }

    @Test
    public void testSave() throws Exception {
        News news = new News();
        news.setTitle("test title");
        news.setAuthor("test author");
        news.setContent("test content");
        news.setPubdate(new Date());

        mockMvc.perform(post("/news/")
                .contentType(MediaType.APPLICATION_JSON)
                .content(new ObjectMapper().writeValueAsString(news)))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.title", is("test title")));

        mockMvc.perform(get("/news/"))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$", hasSize(1)))
                .andExpect(jsonPath("$[0].title", is("test title")));
    }

    @Test
    public void testDelete() throws Exception {
        News news = new News();
        news.setTitle("test title");
        news.setAuthor("test author");
        news.setContent("test content");
        news.setPubdate(new Date());
        newsDao.save(news);

        mockMvc.perform(delete("/news/" + news.getId()))
                .andExpect(status().isOk());

        mockMvc.perform(get("/news/"))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$", hasSize(0)));
    }
}