JAVAWEB realize additions and deletions to change search (book information management) of the modification function realization

　　　　First, by clicking on the index.jsp page of the Modify button, get id of the line: ↓

　　　　　　Then, jump to updateBooks.jsp modification information pages, the page code is as follows: ↓

 1 <%@ page import="BookSystem.Other.Books" %><%--
 2   Created by IntelliJ IDEA.
 3   User: NFS
 4   Date: 2019-7-12
 5   Time: 14:31
 6   To change this template use File | Settings | File Templates.
 7 --%>
 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
 9 <html>
10 <head>
11     <title>修改书籍</title>
12 </head>
13 <body>
14 
15 <%
16     Books books = (Books) request.getAttribute("update");
17 
18     if (books != null) {
19 %>
20 
21 <div>
22     <form method="post" action="update">
23         <label>
24             <span>编号:</span>
25             <input name="book_id" value="<%=books.getId()%>" readonly>
26         </label>
27         <label>
28             <span>书名:</span>
29             <input name="book_name" value="<%=books.getName()%>">
30         </label>
31         <label>
32             <span>作者:</span>
33             <input name="author" value="<%=books.getAuthor()%>">
34         </label>
35         <label>
36             <span>库存:</span>
37             <input name="number" value="<%=books.getNumber()%>">
38         </label>
39         <label>
40             <span>价格:</span>
41             <input name="price" value="<%=books.getPrice()%>">
42         </label>
43         <label>
44             <span>出版社:</span>
45             <input name="pub" value="<%=books.getPub()%>">
46         </label>
47         <input type = "Submit" value = "submit modification information" > 
48      </ form > 
49  </ div > 
50  
51 is  <% 
52 is  } the else {
 53 is  %> 
54 is  < div > This ID No data is found, it can not be modified . </ Div > 
55  <% 
56 is      }
 57 is  %> 
58  
59  
60  < footer > 
61 is      < A the href = "<% = request.getContextPath ()%> / Books / LST" >>
62 </footer>
63 </body>
64 </html>

　　　　　　updateBooks.jsp corresponding servlet: updateBooks.java, code is as follows: ↓

 1 package BookSystem.CRUD;
 2 
 3 import BookSystem.Other.Books;
 4 import BookSystem.Other.DButil;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 import java.io.IOException;
12 import java.sql.*;
13 
14 @WebServlet("/books/update")
15 public class UpdateBooks extends HttpServlet {
16     @Override
17     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
18         //创建Books对象
19         Books books = new Books();
20         //获取对应的id
21         int id = Integer.parseInt(req.getParameter("id"));
22         Connection  connection=null;
23         Statement st = null;
24         ResultSet rs = null;
25         connection=new DButil().getConnection();
26         try {
27             st = connection.createStatement();
28             rs = st.executeQuery("select book_id,book_name ,author,number,price,pub from BookInfo where book_id = "+id);
29             
30             if(rs.next()) {
31                 books =new Books( rs.getInt(1), rs.getString(2), rs.getString(3),rs.getInt(4),rs.getFloat(5),  rs.getString(6));
32 
33             }
34         }catch (SQLException e){
35             e.printStackTrace();
36         }finally {
37             DButil.close(connection,st,rs);
38 
39 
40         }
41         req.setAttribute("update",books);
42         req.getRequestDispatcher("/Book/updateBooks.jsp").forward(req,resp);
43 
44     }
45 
46     @Override
47     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
48        //设置编码格式
49         req.setCharacterEncoding("UTF-8");
50         //获取数据
51         int id=Integer.parseInt(req.getParameter("book_id"));
52         String name=req.getParameter("book_name");
53         String author=req.getParameter("author");
54         Integer number=Integer.parseInt(req.getParameter("number"));
55         Float price=Float.parseFloat(req.getParameter("price"));
56         String pub=req.getParameter("pub");
57         Connection connection=null;
58         PreparedStatement prsmt=null;
59 
60         try {
61             //修改数据
62             connection=new DButil().getConnection();
63             String sql="update BookInfo set book_name =?, author=?, number=?, price=?, pub=? " +
64                     "where book_id=?";
65             prsmt=connection.prepareStatement(sql);
66             prsmt.setString(1,name);
67             prsmt.setString(2,author);
68             prsmt.setInt(3,number);
69             prsmt.setFloat(4,price);
70             prsmt.setString(5,pub);
71             prsmt.setInt(6,id);
72             prsmt.executeUpdate();
73         }catch (SQLException e){
74             e.printStackTrace();
75         }finally {
76             try {
77                 connection.close();
78                 prsmt.close();
79             } catch (SQLException e) {
80                 e.printStackTrace ();
 81              }
 82          }
 83          String Method = req.getMethod ();
 84          
85          resp.sendRedirect (req.getContextPath () + "/ Books / LST");    // redirection, the GET method is certainly 
86      }
 87 }

　　　　　　Note: This does not show the entire CRUD renderings, overall should have their own CSS

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JAVAWEB realize additions and deletions to change search (book information management) of the modification function realization

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