数据库
<%-- Created by IntelliJ IDEA. User: Dell Date: 2021/4/10 Time: 14:34 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <form action="dologin.jsp" method="post"> 用户名：<input type="text" name="username"/><br/> 密码：<input type="password" name="password"/><br/> 验证码：<input type="text" name="inputVcode"/><img src="/WebProject_war_exploded/createCode"><br/> <input type="submit" value="登录"> </form> </body> </html>
<%@ page import="java.sql.*" %><%-- Created by IntelliJ IDEA. User: Dell Date: 2021/4/10 Time: 14:38 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <% String uname = request.getParameter("username"); String upwd = request.getParameter("password"); String inputVcode = request.getParameter("inputVcode").toLowerCase(); String realInputVcode =(String) session.getAttribute("codes"); String realUname=""; String reaslPassword = ""; Class.forName("com.mysql.jdbc.Driver"); Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql","root","root"); PreparedStatement preparedStatement =connection.prepareStatement("SELECT * FROM dl where uname = ?"); preparedStatement.setString(1,uname); ResultSet rs = null; try { rs = preparedStatement.executeQuery(); } catch (SQLException e) { e.printStackTrace(); } //如果有数据，rs.next()返回true while(rs.next()){ realUname = rs.getString("uname"); reaslPassword = rs.getString("upwd"); } if(uname.equals(realUname)&&upwd.equals(reaslPassword)&&inputVcode.equals(inputVcode)){ HttpSession httpSession = request.getSession(); httpSession.setAttribute("username",uname); httpSession.setAttribute("password",upwd); response.sendRedirect("success.jsp"); }else { response.sendRedirect("login.jsp"); } %> </body> </html>
<%-- Created by IntelliJ IDEA. User: Dell Date: 2021/4/10 Time: 15:20 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <% String username =(String) session.getAttribute("username"); if(username==null){ response.sendRedirect("login.jsp"); } %> 欢迎你<%=username %> </body> </html>
package com.dx.yzm; import cn.dsna.util.images.ValidateCode; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "CreateCodeController",value = "/createCode") public class CreateCodeController extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1.创建验证码图片 ValidateCode code = new ValidateCode(200,30,4,20); String codes = code.getCode(); HttpSession session = request.getSession(); session.setAttribute("codes",codes); //2.验证码图片响应给客户端 code.write(response.getOutputStream()); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request,response); } }