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Ajax登錄驗證實現(xiàn)代碼

更新時間：2021年07月12日 10:06:33 作者：wbcra

這篇文章主要為大家詳細介紹了jQuery+ajax實現(xiàn)用戶登錄驗證，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

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中的參數(shù)    preparedStatement   Object[] arr 用來補全sql中的?
    public static int DML(String sql , Object[] arr  ){  // 可變參數(shù) Object ... arr  0~n個參數(shù)
        int update = 0 ;
        try{
            preparedStatement = connection.prepareStatement(sql);
//            循環(huán)完畢，會將sql中全部? 補充齊
            for (int i = 0 ; i < arr.length ; i++){
                preparedStatement.setObject(i+1 , arr[i] );
            }
            update = preparedStatement.executeUpdate();
        }catch (SQLException e){
            e.printStackTrace();
        }
        return update ;
    }
    //     帶參查詢  DQL 操作
    public static ResultSet DQL(String sql , Object[] arr ){
        try{
            preparedStatement = connection.prepareStatement(sql);
//            循環(huán)完畢，會將sql中全部? 補充齊
            for (int i = 0 ; i < arr.length ; i++){
                preparedStatement.setObject(i+1 , arr[i] );
            }
            resultSet = preparedStatement.executeQuery();
        }catch (SQLException e){
            e.printStackTrace();
        }
        return resultSet ;
    }
    //    單獨提供關(guān)閉資源方法
    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層，依賴于dao層 制定某一條sql執(zhí)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層，依賴于dao層 制定某一條sql執(zhí)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.設(shè)置用戶輸入的編碼格式，因為有可能是中文
        req.setCharacterEncoding("utf-8");
        //2.獲取用戶數(shù)輸入的內(nèi)容
        String account = req.getParameter("account");
        String password = req.getParameter("password");
        //3.依據(jù)service來判斷當(dāng)前登錄的賬號密碼是否正確
        //User表 定義一個UserService 用來處理 所有和user有關(guān)的業(yè)務(wù)
        UserService userService = new UserService();
        //login方法傳入賬號密碼  返回是否登錄成功
        boolean flag = userService.login(account,password);
        //4.依據(jù)是否登錄成功，進行控制頁面的跳轉(zhuǎn)
        if (flag){
            req.getRequestDispatcher("success.jsp").forward(req,resp);
        }else {
            req.setAttribute("msg","密碼錯誤，請重新登錄！");
            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.設(shè)置用戶輸入的編碼格式，因為有可能是中文
        req.setCharacterEncoding("utf-8");
        //2.獲取用戶數(shù)輸入的內(nèi)容
        String account = req.getParameter("account");
        //3.依據(jù)service來判斷當(dāng)前登錄的賬號密碼是否正確
        //User表 定義一個UserService 用來處理 所有和user有關(guān)的業(yè)務(wù)
        UserService userService = new UserService();
        //使用check方法  檢出是否存在用戶  true 存在用戶  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) {
        //執(zhí)行select查詢sql語句
        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) {
        //執(zhí)行select查詢sql語句
        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" %>
<html>
<head>
    <title>登錄頁</title>
    <script src="js/jquery-3.6.0.js"></script>
</head>
<body>
    <form action="login">
        賬號：<input id="input1" type="text" name="account" /> <span id="span1"></span> <br/>
        密碼：<input type="password" name="password" /> <span style="color:red"> ${msg } </span><br/>
        <input type="submit" value="登錄"/>
    </form>
</body>
<script>
    // 使用jQuery完成ajax校驗 ，當(dāng)前賬號是否存在
    $("#input1").blur(function () {
        //    發(fā)送ajax請求，獲取到當(dāng)前輸入的賬號是否存在，寫入到span1標簽中
        let account = $("#input1").val();
        $.ajax({
            url:"check",
            // data:{"account":$("#input1").val() },
            data:"account="+account ,
            type:"get",
            success:function (data) {
                let data1 = JSON.parse(data);
                if (data1){
                    // 表示存在當(dāng)前賬號
                    // 可以登錄
                    $("#span1").html("可以登錄");
                    $("#span1").attr("style","color:green");
                }else {
                    $("#span1").html("未注冊");
                    $("#span1").attr("style","color:red");
                }
            }
        })
    })
</script>
</html>

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