本文接着上一篇图书商城分类模块进行学习，供大家参考，具体内容如下

1、创建相关类

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(); /** * 查询所有图书 * @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); } } /** * 按分类查询 * @param cid * @return */ public List<Book> findByCategory(String cid) { try { String sql = "select * from book where cid="; return qr.query(sql, new BeanListHandler<Book>(Book.class), cid); } catch(SQLException e) { throw new RuntimeException(e); } } /** * 加载方法 * @param bid * @return */ public Book findByBid(String bid) { try { /* * 我们需要在Book对象中保存Category的信息 */ String sql = "select * from book where bid="; Map<String,Object> map = qr.query(sql, new MapHandler(), bid); /* * 使用一个Map，映射出两个对象，再给这两个对象建立关系！ */ 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); } } /** * 查询指定分类下的图书本数 * @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); } } /** * 添加图书 * @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); } } /** * 删除图书 * @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(); /** * 查询所有图书 * @return */ public List<Book> findAll() { return bookDao.findAll(); } /** * 按分类查询图书 * @param cid * @return */ public List<Book> findByCategory(String cid) { return bookDao.findByCategory(cid); } public Book load(String bid) { return bookDao.findByBid(bid); } /** * 添加图书 * @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. 得到参数bid * 2. 查询得到Book * 3. 保存，转发到desc.jsp */ request.setAttribute("book", bookService.load(request.getParameter("bid"))); return "f:/jsps/book/desc.jsp"; } /** * 查询所有图书 * @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"; } /** * 按分类查询 * @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、查询所有图书

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

3、按分类查询图书

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

4、查询详细信息（加载）

流程：list.jsp（点击某一本书） -> BookServlet#load() -> desc.jsp

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。