Ajax登录验证实现代码

Ajax登录验证实现代码

目录

package cn.hp.util;

import java.sql.*;

public class JDBCUtils {

static Connection connection = null ;

static Statement statement = null ;

static PreparedStatement preparedStatement = null ;

static ResultSet resultSet = null ;

static{

try {

Class.forName("com.mysql.jdbc.Driver");

connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/user_system?characterEncoding=utf8&serverTimezone=UTC", "root", "root");

} catch (ClassNotFoundException | SQLException e) {

e.printStackTrace();

}

}

// 新增和修改 DML 操作 String sql ， sql中的参数 preparedStatement Object[] arr 用来补全sql中的?

public static int DML(String sql , Object[] arr ){ // 可变参数 Object ... arr 0~n个参数

int update = 0 ;

try{

preparedStatement = connection.prepareStatement(sql);

// 循环完毕，会将sql中全部? 补充齐

for (int i = 0 ; i < arr.length ; i++){

preparedStatement.setObject(i+1 , arr[i] );

}

update = preparedStatement.executeUpdate();

}catch (SQLException e){

e.printStackTrace();

}

return update ;

}

// 带参查询 DQL 操作

public static ResultSet DQL(String sql , Object[] arr ){

try{

preparedStatement = connection.prepareStatement(sql);

// 循环完毕，会将sql中全部? 补充齐

for (int i = 0 ; i < arr.length ; i++){

preparedStatement.setObject(i+1 , arr[i] );

}

resultSet = preparedStatement.executeQuery();

}catch (SQLException e){

e.printStackTrace();

}

return resultSet ;

}

// 单独提供关闭资源方法

public static void close(){

try {

if (statement!=null){

statement.close();

}

if (connection!= null){

connection.close();

}

} catch (SQLException e) {

e.printStackTrace();

}

}

}

package cn.hp.service;

import cn.hp.dao.UserDao;

public class UserService {

public boolean login(String account, String password) {

//service层，依赖于dao层 制定某一条sql执行

UserDao userDao = new UserDao();

int select = userDao.selectByAccountAndPassword(account ,password);

if (select>0){

return true;

}else {

return false;

}

}

public boolean check(String account) {

//service层，依赖于dao层 制定某一条sql执行

UserDao userDao = new UserDao();

int select = userDao.selectByAccount(account);

if (select>0){

return true;

}else {

return false;

}

}

}

package cn.hp.servlet;

import cn.hp.service.UserService;

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 java.io.IOException;

@WebServlet("/login")

public class LoginServlet extends HttpServlet {

@Override

protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

//1.设置用户输入的编码格式，因为有可能是中文

req.setCharacterEncoding("utf-8");

//2.获取用户数输入的内容

String account = req.getParameter("account");

String password = req.getParameter("password");

//3.依据service来判断当前登录的账号密码是否正确

//User表 定义一个UserService 用来处理 所有和user有关的业务

UserService userService = new UserService();

//login方法传入账号密码 返回是否登录成功

boolean flag = userService.login(account,password);

//4.依据是否登录成功，进行控制页面的跳转

if (flag){

req.getRequestDispatcher("success.jsp").forward(req,resp);

}else {

req.setAttribute("msg","密码错误，请重新登录！");

req.getRequestDispatcher("login.jsp").forward(req,resp);

}

}

}

package cn.hp.servlet;

import cn.hp.service.UserService;

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 java.io.IOException;

@WebServlet("/check")

public class CheckServlet extends HttpServlet {

@Override

protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

//1.设置用户输入的编码格式，因为有可能是中文

req.setCharacterEncoding("utf-8");

//2.获取用户数输入的内容

String account = req.getParameter("accountYtKTdOgDNX");

//3.依据service来判断当前登录的账号密码是否正确

//User表 定义一个UserService 用来处理 所有和user有关的业务

UserService userService = new UserService();

//使用check方法 检出是否存在用户 true 存在用户 false 不存在

boolean flag = userService.check(account);

resp.getWriter().println(flag);

}

}

package cn.hp.dao;

import cn.hp.util.JDBCUtils;

import java.sql.ResultSet;

import java.sql.SQLException;

public class UserDao {

public int selectByAccountAndPassword(String account, String password) {

//执行select查询sql语句

String sql = "select count(*) from user where account = ? and password = ?";

Object[] objects = {account , password};

ResultSet resultSet = JDBCUtils.DQL(sql,objects);

int select = 0;

try {

while (resultSet.next()){

select = resultSet.getInt(1);

}

}catch (SQLException e){

e.printStackTrace();

}

return select;

}

public int selectByAccount(String account) {

//执行select查询sql语句

String sql = "select count(*) from user where account = ? ";

Object[] objects = {account };

ResultSet resultSet = JDBCUtils.DQL(sql,objects);

int select = 0;

try {

while (resultSet.next()){

select = resultSet.getInt(1);

}

}catch (SQLException e){

e.printStackTrace();

}

return select;

}

}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

账号：

密码： ${msg }

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。