基于Servlet与JDBC的注册登录系统设计： 1）制作一个学生注册的页面，提交给RegServlet组件处理，能够输入如下数据项： 学号，姓名，昵称，性别，出生日期，所在院系，所选专业，班级，体育爱好（从篮球、足球、排球、羽毛球、乒乓球中多选），音乐爱好（可从钢琴、小提琴、吉他、古筝中多选），英语水平（可从优良、中等、一般中单选）。 2）在RegServlet中获取用户输入数据，并借助JDBC技术，将注册信息保存到数据库中；最后，跳转到注册成功页面，显示该用户的所有注册信息。 3）制作一个用户登录的页面，能够输入用户名、密码登录，表单提交给LoginServlet处理。 4）在LoginServlet中处理用户登录请求，获取输入的用户名和密码，并使用JDBC连接数据库进行验证； 若验证成功，则进入成功页面，显示欢迎信息以及登录的用户名；若验证失败，则进入登录失败页面，提示用户重新登录，并提供超链接。 5）使用数据源改进数据库连接部分的代码，获得更高的数据库访问效率。的代码

以下是基于Servlet与JDBC的注册登录系统的代码：

RegServlet.java

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

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

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取用户输入的数据
        String id = request.getParameter("id");
        String name = request.getParameter("name");
        String nickname = request.getParameter("nickname");
        String gender = request.getParameter("gender");
        String birthday = request.getParameter("birthday");
        String department = request.getParameter("department");
        String major = request.getParameter("major");
        String clazz = request.getParameter("clazz");
        String[] sports = request.getParameterValues("sports");
        String[] musics = request.getParameterValues("musics");
        String englishLevel = request.getParameter("englishLevel");

        // 将用户输入的信息保存到数据库中
        String url = "jdbc:mysql://localhost:3306/test";
        String user = "root";
        String password = "123456";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(url, user, password);
            String sql = "INSERT INTO student (id, name, nickname, gender, birthday, department, major, clazz, sports, musics, english_level) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
            ps = conn.prepareStatement(sql);
            ps.setString(1, id);
            ps.setString(2, name);
            ps.setString(3, nickname);
            ps.setString(4, gender);
            ps.setString(5, birthday);
            ps.setString(6, department);
            ps.setString(7, major);
            ps.setString(8, clazz);
            ps.setString(9, String.join(",", sports)); // 将体育爱好用逗号分隔拼接成字符串
            ps.setString(10, String.join(",", musics)); // 将音乐爱好用逗号分隔拼接成字符串
            ps.setString(11, englishLevel);
            ps.executeUpdate();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (ps != null) {
                    ps.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        // 跳转到注册成功页面，并显示该用户的所有注册信息
        request.setAttribute("id", id);
        request.setAttribute("name", name);
        request.setAttribute("nickname", nickname);
        request.setAttribute("gender", gender);
        request.setAttribute("birthday", birthday);
        request.setAttribute("department", department);
        request.setAttribute("major", major);
        request.setAttribute("clazz", clazz);
        request.setAttribute("sports", String.join(",", sports));
        request.setAttribute("musics", String.join(",", musics));
        request.setAttribute("englishLevel", englishLevel);
        request.getRequestDispatcher("/regSuccess.jsp").forward(request, response);
    }
}

LoginServlet.java

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取用户输入的用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        // 使用JDBC连接数据库进行验证
        String url = "jdbc:mysql://localhost:3306/test";
        String user = "root";
        String pwd = "123456";
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(url, user, pwd);
            String sql = "SELECT * FROM user WHERE username = ? AND password = ?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, username);
            ps.setString(2, password);
            rs = ps.executeQuery();
            if (rs.next()) {
                // 验证成功，跳转到成功页面
                request.setAttribute("username", username);
                request.getRequestDispatcher("/loginSuccess.jsp").forward(request, response);
            } else {
                // 验证失败，跳转到失败页面
                response.sendRedirect("/loginFail.jsp");
            }
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (ps != null) {
                    ps.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

使用数据源改进数据库连接部分的代码

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取用户输入的用户名和密码
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        // 使用数据源连接数据库进行验证
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            Context initCtx = new InitialContext();
            Context envCtx = (Context) initCtx.lookup("java:comp/env");
            DataSource ds = (DataSource) envCtx.lookup("jdbc/test");
            conn = ds.getConnection();
            String sql = "SELECT * FROM user WHERE username = ? AND password = ?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, username);
            ps.setString(2, password);
            rs = ps.executeQuery();
            if (rs.next()) {
                // 验证成功，跳转到成功页面
                request.setAttribute("username", username);
                request.getRequestDispatcher("/loginSuccess.jsp").forward(request, response);
            } else {
                // 验证失败，跳转到失败页面
                response.sendRedirect("/loginFail.jsp");
            }
        } catch (NamingException | SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (ps != null) {
                    ps.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}