圖書商城：圖書子產品

1、建立相關類

• cn.itcast.bookstore.book
• domain：Book
• dao：BookDao
• service :BookService
• web.servle：BookServlet

Book

public class Book {
    private String bid;
    private String bname;
    private double price;
    private String author;
    private String image;
    private Category category;
    private boolean del;
}
           

BookDao

public class BookDao {
    private QueryRunner qr = new TxQueryRunner();

    /**
     * 查詢所有圖書
     * @return
     */
    public List<Book> findAll() {
        try {
            String sql = "select * from book where del=false";
            return qr.query(sql, new BeanListHandler<Book>(Book.class));
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 按分類查詢
     * @param cid
     * @return
     */
    public List<Book> findByCategory(String cid) {
        try {
            String sql = "select * from book where cid=? and del=false";
            return qr.query(sql, new BeanListHandler<Book>(Book.class), cid);
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 加載方法
     * @param bid
     * @return
     */
    public Book findByBid(String bid) {
        try {
            /*
             * 我們需要在Book對象中儲存Category的資訊
             */
            String sql = "select * from book where bid=?";
            Map<String,Object> map = qr.query(sql, new MapHandler(), bid);
            /*
             * 使用一個Map，映射出兩個對象，再給這兩個對象建立關系！
             */
            Category category = CommonUtils.toBean(map, Category.class);
            Book book = CommonUtils.toBean(map, Book.class);
            book.setCategory(category);
            return book;
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 查詢指定分類下的圖書本數
     * @param cid
     * @return
     */
    public int getCountByCid(String cid) {
        try {
            String sql = "select count(*) from book where cid=?";
            Number cnt = (Number)qr.query(sql, new ScalarHandler(), cid);
            return cnt.intValue();
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 添加圖書
     * @param book
     */
    public void add(Book book) {
        try {
            String sql = "insert into book values(?,?,?,?,?,?)";
            Object[] params = {book.getBid(), book.getBname(), book.getPrice(),
                    book.getAuthor(), book.getImage(), book.getCategory().getCid()};
            qr.update(sql, params);
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 删除圖書
     * @param bid
     */
    public void delete(String bid) {
        try {
            String sql = "update book set del=true where bid=?";
            qr.update(sql, bid);
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }

    public void edit(Book book) {
        try {
            String sql = "update book set bname=?, price=?,author=?, image=?, cid=? where bid=?";
            Object[] params = {book.getBname(), book.getPrice(),
                    book.getAuthor(), book.getImage(), 
                    book.getCategory().getCid(), book.getBid()};
            qr.update(sql, params);
        } catch(SQLException e) {
            throw new RuntimeException(e);
        }
    }
}
           

BookService

public class BookService {
    private BookDao bookDao = new BookDao();

    /**
     * 查詢所有圖書
     * @return
     */
    public List<Book> findAll() {
        return bookDao.findAll();
    }

    /**
     * 按分類查詢圖書
     * @param cid
     * @return
     */
    public List<Book> findByCategory(String cid) {
        return bookDao.findByCategory(cid);
    }

    public Book load(String bid) {
        return bookDao.findByBid(bid);
    }

    /**
     * 　添加圖書
     * @param book
     */
    public void add(Book book) {
        bookDao.add(book);
    }

    public void delete(String bid) {
        bookDao.delete(bid);
    }

    public void edit(Book book) {
        bookDao.edit(book);
    }
}
           

BookServlet

public class BookServlet extends BaseServlet {
    private BookService bookService = new BookService();

    public String load(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        /*
         * 1. 得到參數bid
         * 2. 查詢得到Book
         * 3. 儲存，轉發到desc.jsp
         */
        request.setAttribute("book", bookService.load(request.getParameter("bid")));
        return "f:/jsps/book/desc.jsp";
    }

    /**
     * 查詢所有圖書
     * @param request
     * @param response
     * @return
     * @throws ServletException
     * @throws IOException
     */
    public String findAll(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setAttribute("bookList", bookService.findAll());
        return "f:/jsps/book/list.jsp";
    }

    /**
     * 按分類查詢
     * @param request
     * @param response
     * @return
     * @throws ServletException
     * @throws IOException
     */
    public String findByCategory(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String cid = request.getParameter("cid");
        request.setAttribute("bookList", bookService.findByCategory(cid));
        return "f:/jsps/book/list.jsp";
    }
}
           

2、查詢所有圖書

流程：left.jsp（全部分類） -> BookServlet#findAll() -> /jsps/book/list.jsp

3、按分類查詢圖書

流程：left.jsp -> BookServlet#findByCategory() -> list.jsp

4、查詢詳細資訊（加載）

流程：list.jsp（點選某一本書） -> BookServlet#load() -> desc.jsp