连接到Databse-NodeJS和mongodb时出错

Question

我是nodejs和MongoDB的重要成员。尝试连接到数据库时遇到以下错误：

（节点：10124）UnhandledPromiseRejectionWarning：MongoNetworkError：在池上第一次连接[MongoNetworkError：connect Econnn拒绝127.0.0.1:27017]时无法连接到服务器[127.0.0.1:27017].(E:\node js workspace\url-shortner\server\node_modules\mongodb-core\lib\topologies\server.js:562:11)在emitOne（events.js:116:13)在pool.emit（events.js:211:7)在connection。(e:\node js workspace\url-shortner\server\node_modules\mongodb-core\lib\connection\pool.js:316:12)在object.oncewrapper(events.js:317:30)在emitTwoo(events.js:126:13)在connection.emit(events.js:214:7)在socket。(e:\node js workspace\url-shortner\server\node_module\mongodb-core\lib\connection\connection.js:245:50)在object.oncewrapper（events.js:315:30)在emitOne（events.js:116:13)在socket.emit（events.js:211:7)在emitErrorNT（internal/streams/destroy.js:64:8)在_combinedtickcallback（internal/process/next_tick.js:138:11)在这个错误可能是由于抛出一个没有catch块的异步函数内部，或者是由于拒绝了一个未用.catch（）处理的承诺。（拒绝ID：1）（节点：10124）[DEP0018]拒绝警告：不推荐未处理得承诺拒绝.将来，未处理的承诺拒绝将以非零退出代码终止node.js进程。

我正在尝试建立一个url短。这是密码。

index.js-

const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const mongoURI = "mongodb://localhost/url-shortner";
const connectOptions={
keepAlive: true,
reconnectTries: Number.MAX_VALUE
};
mongoose.connect(mongoURI,connectOptions,(err,db)=>{
if(err) console.log('Error',err);
console.log('Connected to MongoDB');
});
const app = express();
require("./models/UrlShorten");
app.use(bodyParser.json());
require("./routes/urlshorten")(app);
const PORT = 7000;
//Start server on Port 7000
  app.listen(PORT, () => {
console.log(`Server started on port`, PORT);
});

urlshorten.js-

const mongoose = require("mongoose");
const validUrl = require("valid-url");
const UrlShorten = mongoose.model("UrlShorten");
const shortid = require("shortid");
const errorUrl='http://localhost/error';
module.exports = app => {
app.get("/api/item/:code", async (req, res) => {
const urlCode = req.params.code;
const item = await UrlShorten.findOne({ urlCode: urlCode });
if (item) {
  return res.redirect(item.originalUrl);
 } else {
   return res.redirect(errorUrl);
 }
});
 app.post("/api/item", async (req, res) => {
 const { originalUrl, shortBaseUrl } = req.body;
 if (validUrl.isUri(shortBaseUrl)) {
 } else {
   return res
     .status(401)
     .json(
       "Invalid Base Url"
     );
 }
 const urlCode = shortid.generate();
 const updatedAt = new Date();
 if (validUrl.isUri(originalUrl)) {
   try {
     const item = await UrlShorten.findOne({ originalUrl: originalUrl });
     if (item) {
       res.status(200).json(item);
     } else {
       shortUrl = shortBaseUrl + "/" + urlCode;
      // console.log("Shorturl: "+shortUrl);
        const item = new UrlShorten({
         originalUrl,
         shortUrl,
         urlCode,
         updatedAt
       });
       await item.save();
       res.status(200).json(item);
     }
    } catch (err) {
    res.status(401).json("Invalid User Id");
   }
  } else {
   return res
     .status(401)
     .json(
       "Invalid Original Url"
     );
 }
});
};

这是架构：

Schema({
originalUrl: String,
urlCode: String,
shortUrl: String,
createdAt: { type: Date, default: Date.now },
updatedAt: { type: Date, default: Date.now }

}）；

谢谢.

Answer 1

您还没有启动mongodb服务,

使用命令sudo mongod启动它，然后尝试启动服务器。