图书管理系统中更新图书信息的实现
图书管理系统中更新图书信息的实现
先行要求
在进行实现图书管理系统添加图书信息功能之前 需要先完成图书管理系统中添加图书信息的实现
分析步骤
①在 booklist-list.jsp 中添加更新选项
②新建一个 BookUpdateUIServlet 利用 book_isbn 获得原图示信息并在book-update.jsp中显示获得的原信息
③在 IBookDao 中添加 findBookByISBN 方法，并在 BookDaoimpl 中完善 updataBook 和 findBookByISBN 方法
④新建 BookUpdateServlet 在该Servlet中使用SQL语句实现数据更新
具体实现
①在 booklist-list.jsp 中添加更新选项
在 table 标签中的tr中添加一条td
<body>
<%
List<Book> books =(List<Book>)request.getAttribute("books");
%>
<table border="1" cellspacing="0">
<tr>
<th>图书ID</th>
<th>图书ISBN</th>
<th>图书名称</th>
<th>图书价格</th>
<th>图书作者</th>
<th>图书出版社</th>
<th>图书数量</th>
</tr>
<%
for(Book book : books)
{
%>
<tr>
<td><%=book.getBookID() %></td>
<td><%=book.getBookISBN() %></td>
<td><%=book.getBookName() %></td>
<td><%=book.getBookPrice() %></td>
<td><%=book.getBookAuthor() %></td>
<td><%=book.getBookPublisher() %></td>
<td><%=book.getBookCount() %></td>
<td><a href="BookUpdateUIServlet?book_isbn=<%=book.getBookISBN() %>">更新</a> <a href="BookDelServlet">删除</a></td>
</tr>
<%
}
%>
</table>
</body>
效果如下：
将 book_isbn 传给 BookUpdateUIServlet
②新建一个 BookUpdateUIServlet 利用 book_isbn 获得原图示信息并在book-update.jsp中显示获得的原信息
在BookUpdateUIServlet中利用dao包里的 findBookByISBN(bookISBN) 方法 封装为一个book对象
package com.software.servlet;
import java.io.IOException;
import javax.annotation.Resource;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.soft.ware.dao.impl.BookDaoimpl;
import com.software.dao.IBookDao;
import com.software.po.Book;
/**
* @author 23501 E-mail: [email protected]
* @version 创建时间：2020年5月8日 上午7:58:46
* tags
*/
@WebServlet("/BookUpdateUIServlet")
public class BookUpdateUIServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html; charset=UTF-8");
String bookISBN = request.getParameter("book_isbn");
IBookDao bookDao = new BookDaoimpl();
//封装
Book book = bookDao.findBookByISBN(bookISBN);
//传递
request.setAttribute("book", book);
request.getRequestDispatcher("book-update.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
将封装好的book对象传给 book-update.jsp
在网页中显示
<%@page import="com.software.po.Book"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>更新图书信息</title>
</head>
<body>
<%
Book book= (Book)request.getAttribute("book");
%>
<form action="BookUpdateServlet" method="post">
<div>
<label for="">图书ISBN</label>
<input type ="text" name="book_isbn" value="<%= book.getBookISBN() %>" readonly="readonly">
</div>
<div>
<label for="">图书名称</label>
<input type ="text" name="book_name" value="<%=book.getBookName()%>">
</div>
<div>
<label for="">图书价格</label>
<input type ="text" name="book_price" value="<%=book.getBookPrice()%>">
</div>
<div>
<label for="">图书作者</label>
<input type ="text" name="book_author" value="<%=book.getBookAuthor()%>">
</div>
<div>
<label for="">图书出版社</label>
<input type ="text" name="book_publisher" value="<%=book.getBookPublisher()%>">
</div>
<div>
<label for="">图书数量</label>
<input type ="text" name="book_count" value="<%=book.getBookCount()%>">
</div>
<button type ="submit">更新</button>
</form>
</body>
</html>
效果如下：
③在 IBookDao 中添加 findBookByISBN 方法，并在 BookDaoimpl 中完善 updataBook 和 findBookByISBN 方法
findBookByISBN 方法
public Book findBookByISBN(String bookISBN) {
Book book = new Book();
try {
Connection conn = DBUtil.getConnection();
String sql = "select * from book where book_isbn=?";
PreparedStatement pst = conn.prepareStatement(sql);
pst.setString(1, bookISBN);
ResultSet rs= pst.executeQuery();
while(rs.next())
{
book.setBookID(rs.getInt("book_id"));
book.setBookISBN(rs.getString("book_isbn"));
book.setBookName(rs.getString("book_name"));
book.setBookPrice(rs.getFloat("book_price"));
book.setBookAuthor(rs.getString("book_author"));
book.setBookPublisher(rs.getString("book_publisher"));
book.setBookCount(rs.getInt("book_count"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
try {
DBUtil.release();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return book;
updataBook 方法
public void updataBook(Book book) {
try {
Connection conn = DBUtil.getConnection();
String sql = "update book set book_name=?,book_price=?,book_author=?,book_publisher=?,book_count=? where book_isbn=? ";
PreparedStatement pst = conn.prepareStatement(sql);
//通过 PreparStatement 对象 为SQL 指令中的“?”进行赋值
pst.setString(1, book.getBookName());
pst.setFloat (2, book.getBookPrice());
pst.setString(3, book.getBookAuthor());
pst.setString(4, book.getBookPublisher());
pst.setInt (5, book.getBookCount());
pst.setString(6, book.getBookISBN());
//ResultSet rs= pst.executeQuery();
int num= pst.executeUpdate();
if(num>0)
{
System.out.println("更新图书信息成功！！！");
}else {
System.out.println("更新图书信息失败...");
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
try {
DBUtil.release();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
④新建 BookUpdateServlet 在该Servlet中使用SQL语句实现数据更新
获取从 book-update.jsp 得到的更新后的图书信息
在 BookUpdateServlet 中调用 update方法 实现数据更新
package com.software.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.soft.ware.dao.impl.BookDaoimpl;
import com.software.dao.IBookDao;
import com.software.po.Book;
/**
* @author 23501 E-mail: [email protected]
* @version 创建时间：2020年5月8日 上午8:36:54
* tags
*/
@WebServlet("/BookUpdateServlet")
public class BookUpdateServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html; charset=UTF-8");
String bookISBN = request.getParameter("book_isbn");
String bookName = request.getParameter("book_name");
float bookPrice = Float.parseFloat(request.getParameter("book_price")) ;//String ->float
String bookAuthor= request.getParameter("book_author");
String bookPublisher = request.getParameter("book_publisher");
int bookCount = Integer.parseInt(request.getParameter("book_count"));//String ->int
//封装成book对象
Book book = new Book(bookISBN, bookName, bookPrice, bookAuthor, bookPublisher, bookCount);
IBookDao bookDao = new BookDaoimpl();
bookDao.updataBook(book);;// 更新数据库中一条记录
response.sendRedirect("index.html");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
到此更新操作完成
效果如下
以上就是图书管理系统中更新图书信息的实现的全过程 如有不恰当的地方 欢迎指正