堆栈跟踪如下： 堆栈跟踪： org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:599) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:478) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) 根本原因
jakarta.servlet.ServletException: java.sql.SQLSyntaxErrorException: 您的 SQL 语法有错误；检查与您的 MariaDB 服务器版本相对应的手册，了解在第 1 行“?,?,?)”附近使用的正确语法 org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:666) org.apache.jsp.add_005fstu_jsp._jspService(add_005fstu_jsp.java:197) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:456) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) 根本原因
java.sql.SQLSyntaxErrorException：您的 SQL 语法有错误；检查与您的 MariaDB 服务器版本相对应的手册，了解在第 1 行“?,?,?)”附近使用的正确语法 com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:121) com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1334) com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2084) com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1245) org.apache.jsp.add_005fstu_jsp._jspService(add_005fstu_jsp.java:151) org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:456) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328) jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
这是 HTML 代码：
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style1.css"/>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Student Registration</title>
</head>
<body>
<div class="container">
<h2>Student Registration</h2>
<form id="add_stu_form" action="add_stu.jsp" method="POST">
<label for="enrol" style="color:black">Enrollment no:</label>
<input type="text" name="enrol" id="enrol" placeholder="Enrollment Number" required>
<label for="fullname" style="color:black">Name:</label>
<input type="text" name="fullname" id="fullname" placeholder="Full Name" required>
<!--button type="submit">Add Student</button-->
<p class="submit">
<input type="submit" name="action" value="Save">
<input type="submit" name="action" value="Delete">
<input type="submit" name="action" value="Update">
</p>
<script></script>
</form>
</div>
</body>
</html>
这是jsp页面：
<%--
Document : add_stu
Created on : 08-Apr-2024, 11:06:07 pm
Author : DC
--%>
<%@ page import="java.sql.*" %>
<%@ page import="java.io.*" %>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con =DriverManager.getConnection("jdbc:mysql://localhost:3306/ams","root","");
long enrl = Long.parseLong(request.getParameter("enrol"));
String name = request.getParameter("fullname");
Statement s0 = con.createStatement();
ResultSet rs0 = s0.executeQuery("SELECT `No` FROM `stu_att`");
int size = 0;
while (rs0.next()) {
size++;
}
int count = size + 1;
int result;
String sql;
String button = request.getParameter("action");
if("Save".equals(button)){
sql = "INSERT INTO `stu_att`(`No`, `name`, `enrl`) VALUES (?,?,?)";
PreparedStatement ps1 = con.prepareStatement(sql);
ps1.setInt(1, count);
ps1.setString(2, name);
ps1.setLong(3, enrl);
result = ps1.executeUpdate(sql);
}
else if("Delete".equals(button)){
long del = enrl; //button2;
sql = "DELETE FROM `stu_att` WHERE `enrl`=?";
PreparedStatement ps2 = con.prepareStatement(sql);
ps2.setLong(1, del);
result = ps2.executeUpdate(sql);
}
else if("Update".equals(button)){
long upd = enrl; //button2;
sql = "UPDATE `stu_att` SET `name`='?' WHERE `enrl`=?";
PreparedStatement ps3 = con.prepareStatement(sql);
ps3.setString(1, name);
ps3.setLong(1, upd);
result = ps3.executeUpdate(sql);
}
else{
result=001;
}
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Add Student</title>
</head>
<body>
<p><%= result %> Record inserted!</p>
<a href="">Back to home page</a>
</body>
</html>
该错误与连接数据库无关，而是与尝试运行时发生错误
INSERT INTO `stu_att`(`No`, `name`, `enrl`) VALUES (?,?,?)
您正在尝试通过
将值传递给此命令 PreparedStatement ps1 = con.prepareStatement(sql);
ps1.setInt(1, count);
ps1.setString(2, name);
ps1.setLong(3, enrl);
result = ps1.executeUpdate(sql);
您需要运行
ps1.execute()ps1.executeUpdate(sql)