使用NetBeans在MS Access数据库中不会发生插入删除更新
在学习了一些Servlets之后，我尝试制作一个简单的学生信息系统。
index.html代码是
<html>
<body bgcolor="AliceBlue">
<h1 style="text-align: center">Student Information System</h1>
<form method="get" action="MIS">
First Name <input type="text" name="FName"/><br><br>
Last Name <input type="text" name="LName"/><br><br>
ID <input type="number" name="ID"/><br><br>
Age <input type="number" name="Age"><br><br>
<input type="submit" name="Insert" value="Insert">
<input type="submit" name="Delete" value="Delete">
<input type="submit" name="Update" value="Update">
</form>
</body>
</html>
在这里，我使用三个按钮插入，更新和删除来对数据库执行相应的操作。
这是MIS.java代码
/*
* 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.
*/
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 javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author Gaurav
*/
@WebServlet(urlPatterns = {"/MIS"})
public class MIS extends HttpServlet {
/**
* 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");
try (PrintWriter out = response.getWriter()) {
/* 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 MIS</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet MIS at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
}
}
// <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 {
response.setContentType("text/html");
PrintWriter pr = response.getWriter();
try
{
Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
Connection con=DriverManager.getConnection("jdbc:ucanaccess://F://Subjects//WT Netbeans//WT P5//src//studentmis.accdb","","");
String FirstName = request.getParameter("FName");
String LastName = request.getParameter("LName");
String Insert = request.getParameter("Insert");
String Update = request.getParameter("Update");
String Delete = request.getParameter("Delete");
int ID = Integer.parseInt(request.getParameter("ID"));
int Age = Integer.parseInt(request.getParameter("Age"));
String SqlInsert="INSERT INTO student_info(Firstname,Lastname,ID,Age)VALUES(?,?,?,?)";
String SqlUpdate="UPDATE student_info SET Lastname=? ID=? Age=? WHERE Firstname=?";
String SqlDelete="DELETE FROM student_info WHERE Firstname=?";
if(Insert!=null)
{
PreparedStatement InsertStatement = con.prepareStatement(SqlInsert);
InsertStatement.setString(1,FirstName);
InsertStatement.setString(2,LastName);
InsertStatement.setInt(3,ID);
InsertStatement.setInt(4,Age);
int RowsInserted = InsertStatement.executeUpdate();
if(RowsInserted > 0)
pr.println("New User Added Successfully");
}
else if(Update!=null)
{
PreparedStatement UpdateStatement = con.prepareStatement(SqlUpdate);
UpdateStatement.setString(1,FirstName);
UpdateStatement.setString(2,LastName);
UpdateStatement.setInt(3,ID);
UpdateStatement.setInt(4,Age);
int RowsUpdated = UpdateStatement.executeUpdate();
if(RowsUpdated > 0)
pr.println("User Updated Successfully");
}
else if(Delete!=null)
{
PreparedStatement DeleteStatement = con.prepareStatement(SqlDelete);
DeleteStatement.setString(1,FirstName);
int RowsDeleted = DeleteStatement.executeUpdate();
if(RowsDeleted > 0)
pr.println("User Updated Successfully");
}
}
catch (ClassNotFoundException | SQLException ex)
{
pr.println(ex);
}
//processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</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 doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
运行项目后， 如果我按下插入按钮（输入信息后），则会出现错误
net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.1 user lacks privilege or object not found: FIRSTNAME
如果我按下删除按钮（输入信息后），则会显示错误
net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.1 user lacks privilege or object not found: FIRSTNAME
如果按下更新按钮（输入信息后），则会显示错误
net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.1 user lacks privilege or object not found: LASTNAME
这是我的MS Access数据库studentmis.accdb包含的内容：
请帮我找到此代码中的问题。如果是数据库身份验证问题，那么我保证我没有为此数据库创建用户名和密码。
此外，我保证我已导入所有必需的.jar文件以使用Ucanaccess驱动程序。
好了，现在解决了其他错误。现在，当我尝试单击更新按钮时，我收到此errornet.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::4.0.1 unexpected token: ID。已修改MIS.java
/*
* 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.
*/
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 javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author Gaurav
*/
@WebServlet(urlPatterns = {"/MIS"})
public class MIS extends HttpServlet {
/**
* 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");
try (PrintWriter out = response.getWriter()) {
/* 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 MIS</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet MIS at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
}
}
// <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 {
response.setContentType("text/html");
PrintWriter pr = response.getWriter();
try
{
Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
Connection con=DriverManager.getConnection("jdbc:ucanaccess://F://Subjects//WT Netbeans//WT P5//src//studentmis.accdb");
String FirstName = request.getParameter("FName");
String LastName = request.getParameter("LName");
String Insert = request.getParameter("Insert");
String Update = request.getParameter("Update");
String Delete = request.getParameter("Delete");
int ID = Integer.parseInt(request.getParameter("ID"));
int Age = Integer.parseInt(request.getParameter("Age"));
String SqlInsert="INSERT INTO student_info(Firstname,Lastname,ID,Age)VALUES(?,?,?,?)";
String SqlUpdate="UPDATE student_info SET Lastname=? ID=? Age=? WHERE Firstname=?";
String SqlDelete="DELETE FROM student_info WHERE Firstname=?";
if(Insert!=null)
{
PreparedStatement InsertStatement = con.prepareStatement(SqlInsert);
InsertStatement.setString(1,FirstName);
InsertStatement.setString(2,LastName);
InsertStatement.setInt(3,ID);
InsertStatement.setInt(4,Age);
int RowsInserted = InsertStatement.executeUpdate();
if(RowsInserted > 0)
pr.println("New User Added Successfully");
}
else if(Update!=null)
{
PreparedStatement UpdateStatement = con.prepareStatement(SqlUpdate);
UpdateStatement.setString(1, LastName);
UpdateStatement.setInt(2,ID);
UpdateStatement.setInt(3,Age);
UpdateStatement.setString(4,FirstName);
int RowsUpdated = UpdateStatement.executeUpdate();
if(RowsUpdated > 0)
pr.println("User Updated Successfully");
}
else if(Delete!=null)
{
PreparedStatement DeleteStatement = con.prepareStatement(SqlDelete);
DeleteStatement.setString(1,FirstName);
int RowsDeleted = DeleteStatement.executeUpdate();
if(RowsDeleted > 0)
pr.println("User Deleted Successfully");
}
}
catch (ClassNotFoundException | SQLException ex)
{
pr.println(ex);
}
//processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</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 doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
1 个答案:
答案 0 :(得分：1)
您收到此错误的原因是您的字段名称不正确，您的字段名称为：
| Field1 | Field1 | Field3 | Field4 |
而不是：
| Firstname | Lastname | ID | Age |
实际上Firstname, Lastname, ID, Age是值，而不是列的名称，因此请更正字段的名称，并且每件事都可以。
修改
net.ucanaccess.jdbc.UcanaccessSQLException：UCAExc ::: 4.0.1意外 令牌：ID
这是逻辑，因为您将属性设置在错误的位置：
UPDATE student_info SET Lastname=? ID=? Age=? WHERE Firstname=?
//--------------------------1----^--2-^--3--^----------4------^
UpdateStatement.setString(1,FirstName);//<<-----this should be Lastname
UpdateStatement.setString(2,LastName);//<<-----this should be ID
UpdateStatement.setInt(3,ID);//<<-----this should be Age
UpdateStatement.setInt(4,Age);//<<-----this should be Firstname
所以改为使用：
UpdateStatement.setString(1, LastName);
UpdateStatement.setInt(2, ID);
UpdateStatement.setInt(3, Age);
UpdateStatement.setString(4, FirstName);
良好做法
请勿在开头UpdateStatement
修改
你错过了yor字段之间的逗号，UPDATE的正确语法是：
UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;
所以在您的查询中：
UPDATE student_info SET Lastname=? ID=? Age=? WHERE Firstname=?
//--------------------------------^----^--miss comma
改为使用：
UPDATE student_info SET Lastname=?, ID=?, Age=? WHERE Firstname=?
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