java - 如何清除JSP程序中的数据库连接错误？

Question

我试图将我的 JSP 登录文件链接到 MySQL 数据库，但收到如下错误。我还将 MySQL-connector jar 文件导入到项目中。我不知道为什么会收到此错误。请帮助我纠正我的错误。

我的代码:

<%@ page import ="java.sql.*" %>
<%
    String userid = request.getParameter("uname");    
    String pwd = request.getParameter("pass");
    Class.forName("com.mysql.jdbc.Driver");
    Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/college",
            "root", "root");
    Statement st = con.createStatement();
    ResultSet rs;
    rs = st.executeQuery("select * from studentdata where uname='" + userid + "' and pass='" + pwd + "'");
    if (rs.next()) {
        session.setAttribute("userid", userid);
        //out.println("welcome " + userid);
        //out.println("<a href='logout.jsp'>Log out</a>");
        response.sendRedirect("success.jsp");
    } else {
        out.println("Invalid password <a href='index.jsp'>try again</a>");
    }
%>

错误消息:

type Exception report

message An exception occurred processing JSP page /login.jsp at line 5

description The server encountered an internal error that prevented it from fulfilling this request.

exception 
org.apache.jasper.JasperException: An exception occurred processing JSP page /login.jsp at line 5

2: <%
3:     String userid = request.getParameter("uname");    
4:     String pwd = request.getParameter("pass");
5:     Class.forName("com.mysql.jdbc.Driver");
6:     Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/college",
7:             "root", "root");
8:     Statement st = con.createStatement();


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)



root cause 
javax.servlet.ServletException: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:916)

Answer 1

您收到此错误:

java.lang.ClassNotFoundException:com.mysql.jdbc.Driver

建议:

1.- 驱动程序 mysql****.jar 是否位于 WEB-INF/lib 文件夹中？

2.- 您是否在类路径中注册了它？

希望对你有帮助