失眠网 > 简单的连接数据库的Web登录界面

简单的连接数据库的Web登录界面

时间：2023-08-15 23:18:36

相关推荐

简单的连接数据库的Web登录界面

一、需求分析

实现在登录界面输入用户名和密码，连接数据库，与数据库信息进行比对，若用户名和密码相互匹配，则显示登陆成功，若不正确，选择重新输入。

二、工具

1.MySql 2.Tomcat 3.Java EE 4.SQLyog或Navicat等，并配置好环境变量。

三、实现步骤

1.数据库建表

首先，创建数据库，并在数据库中创建数据表，表格如图所示：

2.新建项目

打开Eclipse Jee,File–new–Dynamic Web Project.

3.创建JSP、Class文件

1、新建login.jsp文件：

<%@ page language="java" contentType="text/html; charset=utf-8"pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Insert title here</title></head><body><center><h1 style="color:blue">登录</h1><form id="indexform" name="indexForm" action="check.jsp" method="post"><table border="0"><tr><td>账号：</td><td><input type="text" name="username"></td></tr><tr><td>密码：</td><td><input type="password" name="password"></td></tr></table><br><input type="submit" value="登录"></form></center></body></html>

2、新建check.jsp

<%@ page import="java.sql.*" language="java" contentType="text/html; charset=utf-8"pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Insert title here</title></head><body><jsp:useBean id="db" class="Bean.DBBean" scope="page"/><%request.setCharacterEncoding("UTF-8");String username=(String)request.getParameter("username");//获取login页面输入的用户名和密码String password=(String)request.getParameter("password");String sql="select * from users where username="+"'"+username+"'";//定义一个查询语句ResultSet rs=db.executeQuery(sql);//执行查询语句if(rs.next()){//将输入的密码与数据库密码相比对，执行相应操作if(password.equals(rs.getObject("password"))){response.sendRedirect("success.jsp");}else{out.print("<script language='javaScript'> alert('密码错误');</script>");response.setHeader("refresh", "0;url=login.jsp");}}else {out.print("<script language='javaScript'> alert('用户名错误，请重新输入');</script>");response.setHeader("refresh", "0;url=login.jsp");}%></body></html>

3、新建success.jsp

若用户名密码相比配，则显示此页面。

<%@ page language="java" contentType="text/html; charset=utf-8"pageEncoding="utf-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Insert title here</title></head><body style="text-align:center"><h1>登录成功</h1></body></html>

4、创建DBBean.java文件

在该项目下，先创建名为Bean的package文件，然后创建DBBean.java文件：

package Bean;import java.sql.*;public class DBBean {private String driverStr = "com.mysql.jdbc.Driver";private String connStr = "jdbc:mysql://localhost:3306/test";private String dbusername = "root";private String dbpassword = "root";private Connection conn = null;private Statement stmt = null;public DBBean(){try{Class.forName(driverStr);conn = DriverManager.getConnection(connStr, dbusername, dbpassword);stmt = conn.createStatement();} catch (Exception ex) {System.out.println(ex.getMessage());System.out.println("数据连接失败！");} }public int executeUpdate(String s) {int result = 0;System.out.println("--更新语句:"+s+"\n");try {result = stmt.executeUpdate(s);} catch (Exception ex) {System.out.println("执行更新错误！");}return result;}public ResultSet executeQuery(String s) {ResultSet rs = null;System.out.print("--查询语句:"+s+"\n");try {rs = stmt.executeQuery(s);} catch (Exception ex) {System.out.println("执行查询错误！");}return rs;}public void execQuery(String s){try {stmt.executeUpdate(s);} catch (SQLException e) {System.out.println("执行插入错误！");}}public void close() {try {stmt.close();conn.close();} catch (Exception e) {}}}

5、导入Mysql包

将mysql-connector-java-5.1.7-bin.jar拷贝到tomcat下lib目录即可。