JSP，mysql和JDBC连接[重复]

Question

我一直在使用我曾经在我的项目中使用的代码制作注册页面，该代码 100% 正确，但是这次我遇到了错误。我已经添加了所有的库和罐子

我仍然不断收到类似的错误

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>CodeGyan - Learn Programming Online</title>
<link rel="icon" href="images/logo.png" type="image/x-icon">

</head>
<body>
<%@ page import="java.sql.*"%>
<%@ page import="javax.sql.*"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.Statement"%>
<%@page import="java.sql.Connection"%>
<%
String firstname=request.getParameter("firstname");
String lastname=request.getParameter("lastname");
String username=request.getParameter("username");
session.putValue("username",username);
String pwd=request.getParameter("pwd");
String email_id=request.getParameter("email_id");

Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/codegyan", "CinthiyaSingh", "Cinthiya@098");
//selecting username from users table
PreparedStatement ps = con.prepareStatement("select *from users where username=?");
ps.setString(1, username);
ResultSet rs = ps.executeQuery();

PreparedStatement ps1 = con.prepareStatement("select *from users where email_id=?");
ps1.setString(1, email_id);
ResultSet rs1 = ps1.executeQuery();
//if true
if (rs.next()) {
 //sending error message on Register page
 request.getSession().setAttribute("errorMessage", "Already Existing Username, Please Try Again With a Unique Username! ");
 request.getRequestDispatcher("register.jsp").forward(request, response);


 
}
else if(rs1.next()){
        request.getSession().setAttribute("errorMessage", "Already Existing Email, Please Try Again With Valid Email-ID! ");
        request.getRequestDispatcher("register.jsp").forward(request, response);
} 
else {
 //If not exist performing insert 
 PreparedStatement ps2 = con.prepareStatement("insert into users values(?,?,?,?,?)");
 //setting value for "?"
 ps2.setString(1, username);
 ps2.setString(2, pwd);
 ps2.setString(3, firstname);
 ps2.setString(4, lastname);
 ps2.setString(5, email_id);
 int i = ps2.executeUpdate();
 //if updated successfully
 if (i > 0) {
  //redirect
    request.getSession().setAttribute("errorMessage", "Registered Successfully! Please Login to Fill The Form ");
    request.getRequestDispatcher("login.jsp").forward(request, response);
 }  
//close connection
con.close();
}
%>

</body>
</html>

我有一个页面 (jsp) 页面，其中有表单。该页面的名称是Register.jsp。我已经按照构建路径的方法添加了 jars 仍然没有改变。

Answer 1

错误消息表明您缺少依赖项。 尝试将此添加到您的pom.xml

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.26</version>
</dependency>

在 cmets 中告诉我这是否适合您，或者我们需要进一步调试？