我可以从其他方式加载我的 mysql jdbc 驱动程序，但是当我尝试使用 servletconfig 接口注册它时，它给出了异常
java.lang.ClassNotFoundException：驱动器
虽然我知道 servletconfig 接口的概念并尝试遵循该概念来实现但失败了。
这是我的代码和我使用的其他东西。
这是我的java类
package com.pi.org;
import java.io.IOException;
import javax.sql.*;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Validation
*/
public class Validation extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Validation() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
Boolean valid= false;
PrintWriter out = response.getWriter();
String username= request.getParameter("user");
String password= request.getParameter("pass");
try{
ServletConfig config = getServletConfig();
String driver = config.getInitParameter("driver");
Class.forName("driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/newdata","root","annie1993");
PreparedStatement ps= conn.prepareStatement("select * from emp ");
ResultSet rs = ps.executeQuery();
while(rs.next()){
if(username.equals(rs.getString(1))&& password.equals(rs.getString(2)))
{
valid= true;
}
}
if(valid)
{
request.setAttribute("user", username);
RequestDispatcher rd = request.getRequestDispatcher("inbox");
rd.forward(request, response);
}
else{
RequestDispatcher rd = request.getRequestDispatcher("/index");
rd.include(request, response);
out.print("<html><body>either username or password is incorrect<body><html>");
}
}catch(Exception e){e.printStackTrace();}
}
}
错误是因为没有“驱动程序”类，正确的句子是：
Class.forName("com.mysql.jdbc.Driver");
or
Class.forName( config.getInitParameter("driver") );
但实际上这不是在 servlet 中访问数据库的正确方法，请参阅：Class.forName("com.mysql.jdbc.Driver").newInstance() https://stackoverflow.com/questions/19412135/class-fornamecom-mysql-jdbc-driver-newinstance
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