jdbc 连接报错（基础测试例子）

Question

小例子流程：点击test.jsp页面链接--通过请求转发--跳转到students.jsp页面--显示从mysql数据库表中读取的学生数据。

win10, 虚拟机 centos7，docker, mysql5.7 环境。

错误如下：（应该是少jar包）

package com.atguigu.javaweb.mvc;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ListAllStudentsServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;


    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        StudentDao studentDao = new StudentDao();
        List<Student> students = studentDao.getAll();
        
        request.setAttribute("students", students);
        request.getRequestDispatcher("/students.jsp").forward(request, response);
        
    }

}

studentDao.java

package com.atguigu.javaweb.mvc;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ListAllStudentsServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;


    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        StudentDao studentDao = new StudentDao();
        List<Student> students = studentDao.getAll();
        
        request.setAttribute("students", students);
        request.getRequestDispatcher("/students.jsp").forward(request, response);
        
    }

}

mysql应该是正常的。IDEA测试项目可以建表。

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发现linux虚拟机IP地址变了，改过之后开始还报错，后来就好了...

Answer 1

请检查mysql是否正确启动，另外如果是本地部署，可尝试将ip地址改为127.0.0.1。