问题遇到的现象和发生背景
用java servlet向数据库中添加数据
问题相关代码，请勿粘贴截图
<%--
Document : insertform
Created on : 2022-6-8, 22:49:46
Author : Wenny
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<div style=" width: 400px;height: 500px; margin: 0 auto;">
${message}
<form action="./productsaddServlet" method="post">
<table border="1">
<tr>
<td>编号</td>
<td><input type="text" name="id"></td>
</tr>
<tr>
<td>商品名称</td>
<td><input type="text" name="pname"></td>
</tr>
<tr>
<td>品牌</td>
<td><input type="text" name="brand"></td>
</tr>
<tr>
<td>价格</td>
<td><input type="text" name="price"></td>
</tr>
<tr>
<td>库存</td>
<td><input type="text" name="stock"></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="添加"></td>
</tr>
</table>
</form>
</div>
</body>
</html>
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package newpackage;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author Wenny
*/
@WebServlet(name = "productsaddServlet", urlPatterns = {"/productsaddServlet"})
public class productsaddServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
/* TODO output your page here. You may use following sample code. */
out.println("<!DOCTYPE html>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet productsaddServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet productsaddServlet at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/ @Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response); }
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf8");
Connection conn=null;
PreparedStatement add=null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/exercise5", "root", "123456");
String name=request.getParameter("pname");
int pid2=Integer. parseInt (request.getParameter("id"));
float price=Float. parseFloat(request.getParameter("price"));
String brand=request.getParameter("brand");
int stock=Integer. parseInt(request.getParameter("stock"));
String sql2="insert into products(id,p_name,brand,price,stock) values("+pid2+","
+ "'"+name+"','"+brand+"',"+price+ ","+stock+")";
add=conn.prepareStatement(sql2);
int num=add.executeUpdate();
if(num>0)
{
request.setAttribute("message","添加成功");
request.getRequestDispatcher("/insertform.jsp").forward(request, response);
}
} catch (ClassNotFoundException ex) {
Logger.getLogger(productsaddServlet.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(productsaddServlet.class.getName()).log(Level.SEVERE, null, ex);
}finally
{
try {
if(add!=null)
{
add.close();
}
if(conn!=null)
{
conn.close();
}
} catch (SQLException ex) {
Logger.getLogger(productsaddServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
运行结果及报错内容
我的解答思路和尝试过的方法
一片空白连添加成功都没有，只知道那个有一个为空但不知道为什么
