Announcement

实体类代码：

```
public class Announcement {
    private int id;
    private String content;
    private String title;
    private Date createTime;

    // getter and setter methods
}
```

Mapper接口代码：

```
public interface AnnouncementMapper {
    void addAnnouncement(Announcement announcement);

    List<Announcement> findAnnouncementsByKeyword(String keyword);

    void updateTitleById(@Param("id") int id, @Param("title") String title);

    void deleteAnnouncementById(int id);
}
```

测试类代码：

```
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath*:applicationContext.xml"})
public class AnnouncementMapperTest {
    @Autowired
    private AnnouncementMapper announcementMapper;

    @Test
    public void testAddAnnouncement() {
        Announcement announcement = new Announcement();
        announcement.setContent("Content");
        announcement.setTitle("Title");
        announcement.setCreateTime(new Date());
        announcementMapper.addAnnouncement(an