dl.jsp文件
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>登陆界面</title> </head> <body background="image\td.jpg"> <body> <form action="LoginServlet" method="get"> 账号：<input type="text" name="username" value=""><br> 密码：<input type="password" name="password" value="123456"><br> <input type="radio" id="radio-1" name="type" checked value="1" /> <label>顾客</label> <input type="radio" id="radio-2" name="type" value="2" /> <label>房产经纪</label> <input type="radio" id="radio-3" name="type" value="3" /> <label>管理员</label> <br> <input type= "hidden" name="method" value="login"> <input type="submit" value="登录"><br><a style="color:blue" href='stuzc.jsp?' onclick="del()">没有账号？注册一个！</a> </form> </body> </body> </html>
serlvet页面
package Servlet;
import Dao.AdminDao;
import Dao.GukeDao;
import Dao.GuanliDao;
import Bean.gl;
import Bean.*;
import Bean.guk;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import java.io.IOException;
import Dao.stuad;
@WebServlet("/LoginServlet")
public class Login extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String method=request.getParameter("method");
if("login".equals(method)) {
try { Login(request,response);
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}}
if("zhuce".equals(method)) {
try { Zhuce(request,response);
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}}
}
protected void Login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
String username= request.getParameter("username");
String password = request.getParameter("password");
//获取选择登陆对象的类型参数
int type = Integer.parseInt(request.getParameter("type"));
//验证码验证
//验证码验证通过，对比用户名密码是否正确
switch (type) {
case 1:{
GukeDao gukeDao = new GukeDao();
guk guke = gukeDao.login(username,password);
gukeDao.closeCon();
if (guke == null)
{
response.getWriter().write("顾客登录失败");
response.setHeader("refresh","2;URL=dl.jsp");
return;
}else {
HttpSession session = request.getSession();
session.setAttribute("user", guke);
session.setAttribute("userType", type);
response.getWriter().write("顾客登录成功，2s后返回顾客页面");
response.setHeader("refresh","2;URL=gkzhu.jsp");
}
break;
}
case 2:{
AdminDao adminDao = new AdminDao();
adm admin = adminDao.login(username,password);
adminDao.closeCon();
if(admin == null){
response.getWriter().write("房产经纪登录失败");
response.setHeader("refresh","2;URL=dl.jsp");
return;
}else{
HttpSession session = request.getSession();
session.setAttribute("user", admin);
session.setAttribute("userType", type);
response.getWriter().write("房产经纪登录成功，2s后返回页面");
response.setHeader("refresh","2;URL=jingji.jsp");
}
break;
}
case 3:{
GuanliDao guanliDao = new GuanliDao();
gl guanli = guanliDao.login(username, password);
guanliDao.closeCon();
if(guanli == null){
response.getWriter().write("管理员登录失败");
response.setHeader("refresh","2;URL=dl.jsp");
return;
}else {
HttpSession session = request.getSession();
session.setAttribute("user", guanli);
session.setAttribute("userType", type);
response.getWriter().write("管理员登录成功,2s进入管理员登录·页面");
response.setHeader("refresh","2;URL=admin.jsp");
}
break;
}
default:
break;
}
}
protected void Zhuce(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//设置响应类型,并防止中文乱码
stuad A =new stuad();
int i = 0;
String username= request.getParameter("username");
String password = request.getParameter("password");
String idnumber= request.getParameter("idnumber");
String user= request.getParameter("user");
String phone= request.getParameter("phone");
String sex= request.getParameter("sex");
String name= request.getParameter("name");
guk B = new guk();
B.setIdnumber(idnumber);
B.setName(name);
B.setPassword(password);
B.setPhone(phone);
B.setSex(sex);
B.setUser(user);
B.setUsername(username);
System.out.println(name);
try {
i=A.add(B);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(i==1)
{ response.getWriter().append("注册成功！2s后返回登录页面");
response.setHeader("refresh","2;URL=dl.jsp");}
else
response.getWriter().append("注册失败！");
}
}
bean文件这里不做添加，bean文件可以不只有我们所需的username以及password，bean文件可以把所需数据库表中的内容都添加进去，用哪个调用哪个
util文件
package Utils;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/**
*
* @author llq
*数据库连接util
*/
public class DbUtil {
private String dbUrl ="jdbc:mysql://localhost:3306/house?serverTimezone=UTC";
private String dbUser = "root";
private String dbPassword = "Zhaowenzhe1007";
private String jdbcName = "com.mysql.jdbc.Driver";
private Connection connection = null;
public Connection getConnection(){
try {
Class.forName(jdbcName);
connection = DriverManager.getConnection(dbUrl, dbUser, dbPassword);
System.out.println("数据库连接成功");
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("数据库连接失败");
e.printStackTrace();
}
return connection;
}
public void closeCon(){
if(connection != null)
try {
connection.close();
System.out.println("数据库连接已关闭");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
//创建一个数据库对象
DbUtil dbUtil = new DbUtil();
//连接数据库
dbUtil.getConnection();
}
}
Dao文件中的basedao文件
package Dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import Utils.DbUtil;
public class BaseDao {
private DbUtil dbUtil = new DbUtil();
/**
* 及时关闭数据库连接，释放资源
*/
/**
* 基础查询，多条查询
*/
public ResultSet query(String sql){
try {
PreparedStatement prepareStatement = dbUtil.getConnection().prepareStatement(sql);
return prepareStatement.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
*增删改
*/
public boolean update(String sql){
try {
return dbUtil.getConnection().prepareStatement(sql).executeUpdate() > 0;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return false;
}
public Connection getConnection(){
return dbUtil.getConnection();
}
}
举例用的
package Dao;
import java.sql.ResultSet;
import java.sql.SQLException;
import Bean.adm;
/**
*
* @author llq
*管理员数据库操作封装
*/
public class AdminDao extends BaseDao {
//将从表单获取到的username和password作为参数传入，返回一个在数据库的user表中对应了用户名和密码的user对象
/*
* 1、如果成功返回一个user对象说明在数据库中找到和表单输入对应的用户名和密码，登录成功
* 2、如果返回为空说明在数据库中没有找到和表单对应的用户名和密码，登录失败*/
public adm login(String username , String password){
String sql = "select * from admin where username = '" + username + "' and password = '" + password + "'";
ResultSet resultSet = query(sql);
try {
if(resultSet.next()){
adm admin = new adm();
admin.setAgentid(resultSet.getString("id"));
admin.setUsername(resultSet.getString("username"));
admin.setPassword(resultSet.getString("password"));
return admin;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
public void closeCon() {
// TODO Auto-generated method stub
}
}
根据文件类型修改文件的sql语句即可，多用户登录和单用户登录原理相同，都是采用查找在数据库中进行账号查找，再将密码传出来和输入的密码进行匹配是否相等。而所多便是serlvet中switch语句，根据登录jsp文件传递的type选项，调用不同的语句来进行执行，最终实现登录
标签：String,多用户,request,登陆,注册,sql,catch,import,response From： https://www.cnblogs.com/azwz/p/16990790.html