Question

我正在通过cron.Job（）每天删除数据并将其插入数据库。但是插入一些数据后，服务器上的数据库结果不会刷新。

我在这里找到了2个答案。但是不能理解其中一个而另一个也老了。

在代码中我首先截断表，然后我插入新数据。但是当我发送请求时，它会向我显示旧数据。

在get_pharmacy.js中，我只是做一些排序操作并向用户发送响应。

这是我的代码：

var port = 4000;
var express = require("express");
var bodyParser = require('body-parser');
var get_pharmacy = require("./routes/get_pharmacy.js");
var app = express();
var path = require("path");
var cron = require('cron');

app.use('/static',express.static(path.join(__dirname, 'static')));
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({ extended: true }));
app.use("/get_pharmacy", get_pharmacy);

var job1 = new cron.CronJob({
    cronTime: '55 59 21 * * 1-7', // 00 00 22
    onTick: function() {
        var deleter = require("/home/ahmet/development_nuri/deleter.js");
    },
    start: false,
timeZone: 'America/Los_Angeles'
});

var job2 = new cron.CronJob({
    cronTime: '00 00 22 * * 1-7', // 00 00 22
    onTick: function() {
        var istanbul = require("/home/ahmet/development_nuri/scrap.js");
    },
    start: false,
    timeZone: 'America/Los_Angeles'
});
job1.start();
job2.start();

process.on('uncaughtException', function (err) {
    console.log('UNCAUGHT', err.stack);
});

app.listen(port);

get_pharmacy.js（请求来到这里）

var express = require("express");
var mysql = require('mysql');
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "159487aa",
    database: "eczane",
    debug: false
});
var cities = [];

const router = express.Router();

setInterval(function () {
    con.query('SELECT 1');
}, 5000);

function swap(a,b)
{
  var temp=a;

}

function sortMeThender(data)
{

    var array = []
    for(var i=0; i<data.length; i++)
    {
        for(var x=0;  x<data.length; x++)
        {
            if(data[i]["distance"] < data[x]["distance"])
            {
                var temp=data[x];
                 data[x]=data[i];
                 data[i]=temp;
            }
        }
    }

    array.push(data[0]);
    array.push(data[1]);
    array.push(data[2]);
    array.push(data[3]);
    array.push(data[4]);
    return array;

}

router.route("/")
    .post(function(request, response) {

        var lat = request.body.lat;
        var long = request.body.long;

            con.query("select name,adress,town,city,phone,latitude,longitude from eczane", function (err, result) {
                if (err) throw err;
                cities.push(result);
                for (var i = 0; i < cities[0].length; i++) {
                    cities[0][i]["distance"] = getDistanceFromLatLonInKm(lat, long, cities[0][i]["latitude"], cities[0][i]["longitude"]);
                }
                response.send(sortMeThender(cities[0]));
            });

        function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {

            var R = 6371; // Radius of the earth in km
            var dLat = deg2rad(lat2-lat1);  // deg2rad below
            var dLon = deg2rad(lon2-lon1);
            var a =
                Math.sin(dLat/2) * Math.sin(dLat/2) +
                Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *
                Math.sin(dLon/2) * Math.sin(dLon/2)
            ;
            var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
            var d = R * c; // Distance in km
            return d * 1000;
        }

        function deg2rad(deg) {
            return deg * (Math.PI/180)
        }
    });

module.exports = router;

Answer 1

get_pharmacy.js中的cities变量是全局的。将其更改为本地（在post方法中使用它）。

NodeJS不断刷新数据库表的数据

1 个答案: