SSMP小案例Service层

编写Service接口

```
public interface BookService {
    Boolean save(Book book);
    Boolean delete(Integer id);
    Boolean update(Book book);
    Book getById(Integer id);
    List<Book> getAll();
    IPage<Book> getByPage(int currentPage, int pageSize);
    
}

```

实现service接口

  ```
@Service
public class BookServiceImpl2 implements BookService {
    @Autowired
    private BookMapper bookMapper;


    @Override
    public Boolean save(Book book) {
        return bookMapper.insert(book)>0;
    }

    @Override
    public Boolean delete(Integer id) {
        return bookMapper.deleteById(id)>0;
    }

    @Override
    public Boolean update(Book book) {
        return bookMapper.updateById(book)>0;
    }

    @Override
    public Book getById(Integer id) {
        return bookMapper.selectById(id);
    }

    @Override
    public List<Book> getAll() {
        return bookMapper.selectList(null);
    }

    @Override
    public IPage<Book> getByPage(int currentPage, int pageSize) {
        IPage page = new Page(currentPage,pageSize);
        return bookMapper.selectPage(page,null);
    }
}
```

这里需要注意一下，因为返回的是Boolean类型，所以要写>0进行逻辑判断。

然后就是编写service的测试用例

```
@SpringBootTest
public class BookServiceTestCase {
    @Autowired
    private Book book;
    @Autowired
    private BookService bookService;
    @Test
    void testGetById(){
        System.out.println(bookService.getById(4));
    }
    /**
     * 测试增加
     */
    @Test
    void testSave(){
        book.setType("测试数据123");
        book.setName("测试数据123");
        book.setDescription("测试数据123");
        bookService.save(book);
    }

    /**
     * 测试更新
     */
    @Test
    void testUpdate(){
        book.setId(5);
        book.setType("测试数据123aaa");
        book.setName("测试数据123sds");
        book.setDescription("测试数据123aaa");
        bookService.update(book);
    }

    /**
     * 测试删除
     */
    @Test
    void testDelete(){
        System.out.println(bookService.delete(19));
    }

    /**
     * 测试查询全部
     */
    @Test
    void testGetAll(){
        System.out.println(bookService.getAll());
    }

    /**
     * 测试分页
     */
    @Test
    void testGetPage(){

        IPage<Book> page = bookService.getByPage(2, 5);
        System.out.println(page.getCurrent());//当前的页码
        System.out.println(page.getSize());//每页多少数据
        System.out.println(page.getTotal());//总记录条数
        System.out.println(page.getRecords());//数据
    }




}
```