用户输入表单后显示数据（mysql-nodejs）

Posted 2023-02-24

【中文标题】用户输入表单后显示数据（mysql-nodejs）

【英文标题】：Display data after user input form (mysql-nodejs)

【发布时间】：2021-08-17 09:52:12

【问题描述】：

我有一个页面，其中有一个表单，用户将在其中填写输入。然后，我重定向到另一个页面，根据用户的选择，将显示一些数据（数据将来自 mysql 数据库）。这是我的代码：index.js（这是我的路线）

var express = require('express');
var router = express.Router();

// Controllers
const airTicketsController = require('../controllers/airTicketsController');

/* GET home page. */
router.get('/', function(req, res, next) 
    res.render('home',  title: 'Express' );
);

// Air tickets page
router.get('/air_tickets', function(req, res, next) 
    res.render('air_tickets',  title: 'Air tickets' );
);

router.post('/form-submit', airTicketsController.airForm);
router.get('/air_ticketsSelect', airTicketsController.displayFlights);

module.exports = router;

airTicketsController.js（将执行 mysql 查询的控制器）

const mysql = require('mysql');

// DB connection
const connection = mysql.createConnection(
    host: 'localhost',
    user: 'myuser',
    password: 'mypassword',
    database: 'mydatabase'
);

connection.connect(function(error) 
    if (!!error) console.log(error);
    else console.log('CONGRATS! Database Connected! (airTicketsController)');
);

var variable1, variable2;

exports.airForm= (req, res) => 
    variable1 = req.body.from_destination;
    variable2 = req.body.to_destination
    res.redirect('/air_ticketsSelect');


exports.displayFlights= (req, res) => 
    variable1 = req.body.from_destination;
    variable2 = req.body.to_destination
    connection.query("SELECT * FROM flight WHERE from_destination=? AND to_destination=?", [variable1, variable2], function(err, results, fields) 
        if (err) throw err;
        res.render('air_ticketsSelect', 
            title: 'flightdata',
            data: results
        );
    );

air_tickets.ejs（表单页面）

<form id="form-submit" method="post" action="form-submit">
                            <div class="container" id="air-form-container">
                                <div class="row">
                                    <div class="col-md-6">
                                        <div class="form-group">
                                            <label for="from_destination">From: </label>
                                            <br>
                                            <input type="text" name="from_destination" class="form-control" placeholder="City or airport">
                                        </div>
                                    </div>
                                    <div class="col-md-6">
                                        <div class="form-group">
                                            <label for="to_destination">To: </label>
                                            <br>
                                            <input type="text" name="to_destination" class="form-control" placeholder="City or airport">
                                        </div>
                                    </div>
                                </div>
                                <br>
                                <div class="row">
                                    <div class="col-md-12">
                                        <div class="form-btn">
                                            <button type="submit" class="btn btn-primary" id="submit-btn">Search flights 
                                            <i class="fas fa-search" aria-hidden="true"></i>
                                        </button>
                                        </div>
                                    </div>
                                </div>
                            </div>
                        </form>

air_ticketsSelect.ejs（显示数据的页面）

<table class="table table-dark table-striped">
                        <thead>
                            <tr>
                                <th>Id</th>
                                <th>Airline</th>
                                <th>From</th>
                                <th>To</th>
                                <th>Depart date</th>
                                <th>Arrival date</th>
                                <th>Depart time</th>
                                <th>Arrival time</th>
                                <th>Price</th>

                            </tr>
                        </thead>
                        <tbody>
                            <% data.forEach(function(flight) %>
                                <tr>
                                    <td>
                                        <%= flight.flight_id %>
                                    </td>
                                    <td>
                                        <%= flight.airline %>
                                    </td>
                                    <td>
                                        <%= flight.from_destination %>
                                    </td>
                                    <td>
                                        <%= flight.to_destination %>
                                    </td>
                                    <td>
                                        <%= flight.depart_date.toLocaleDateString('el-GR') %>
                                    </td>
                                    <td>
                                        <%= flight.arrival_date.toLocaleDateString('el-GR') %>
                                    </td>
                                    <td>
                                        <%= flight.depart_time %>
                                    </td>
                                    <td>
                                        <%= flight.arrival_time %>
                                    </td>
                                    <td>
                                        <%= flight.flight_price + ' €' %>
                                    </td>
                                </tr>
                                <% ); %>
                        </tbody>
                    </table>

一般来说，我认为这应该可行。但是，它不显示数据，只显示一个空表。如果我手动进行查询（例如 SELECT * FROM flight WHERE from_destination = 'Paris' AND to_destination = 'London'），它将正常工作.. 当我 console.log 查询时，它说： sql: 'SELECT * FROM flight WHERE from_destination=NULL AND to_destination=NULL', 值：[未定义，未定义]

【参考方案1】：

您错误地双重定义变量。

在exports.displayFlights 中无需再次初始化变量，删除这两行即可解决您的问题。

由于exports.displayFlights 中没有req.body，因此您的变量将被初始化为undefined。