如果你有Express.js，你可以使用express- MongoDB -db在请求之间缓存和共享MongoDB连接，而不需要一个池(因为接受的答案说这是共享连接的正确方式)。

如果没有，你可以查看它的源代码并在另一个框架中使用它。

实现连接池的最佳方法是创建一个全局数组变量，其中包含由MongoClient返回的db名称和连接对象，然后在需要联系数据库时重用该连接。

In your Server.js define var global.dbconnections = []; Create a Service naming connectionService.js. It will have 2 methods getConnection and createConnection. So when user will call getConnection(), it will find detail in global connection variable and return connection details if already exists else it will call createConnection() and return connection Details. Call this service using <db_name> and it will return connection object if it already have else it will create new connection and return it to you.

希望能有所帮助。

下面是connectionService.js的代码:

var mongo = require('mongoskin');
var mongodb = require('mongodb');
var Q = require('q');
var service = {};
service.getConnection = getConnection ;
module.exports = service;

function getConnection(appDB){
    var deferred = Q.defer();
    var connectionDetails=global.dbconnections.find(item=>item.appDB==appDB)

    if(connectionDetails){deferred.resolve(connectionDetails.connection);
    }else{createConnection(appDB).then(function(connectionDetails){
            deferred.resolve(connectionDetails);})
    }
    return deferred.promise;
}

function createConnection(appDB){
    var deferred = Q.defer();
    mongodb.MongoClient.connect(connectionServer + appDB, (err,database)=> 
    {
        if(err) deferred.reject(err.name + ': ' + err.message);
        global.dbconnections.push({appDB: appDB,  connection: database});
        deferred.resolve(database);
    })
     return deferred.promise;
} 

npm i express mongoose

mongodb.js

const express = require('express');
const mongoose =require('mongoose')
const app = express();

mongoose.set('strictQuery', true);
mongoose.connect('mongodb://localhost:27017/db_name', {
    useNewUrlParser: true, 
    useUnifiedTopology: true
})
.then(() => console.log('MongoDB Connected...'))
.catch((err) => console.log(err))

app.listen(3000,()=>{ console.log("Started on port 3000 !!!") })

node mongodb.js

使用下面的方法，您可以轻松地管理尽可能多的连接

var mongoose = require('mongoose');


//Set up default mongoose connection
const bankDB = ()=>{
    return  mongoose.createConnection('mongodb+srv://<username>:<passwprd>@mydemo.jk4nr.mongodb.net/<database>?retryWrites=true&w=majority',options);
    
}

bankDB().then(()=>console.log('Connected to mongoDB-Atlas bankApp...'))
       .catch((err)=>console.error('Could not connected to mongoDB',err));
       
//Set up second mongoose connection
const myDB = ()=>{
    return  mongoose.createConnection('mongodb+srv://<username>:<password>@mydemo.jk4nr.mongodb.net/<database>?retryWrites=true&w=majority',options);
   
}
myDB().then(()=>console.log('Connected to mongoDB-Atlas connection 2...'))
       .catch((err)=>console.error('Could not connected to mongoDB',err));

module.exports = { bankDB(), myDB() };

下面是一些管理MongoDB连接的代码。

var MongoClient = require('mongodb').MongoClient;
var url = require("../config.json")["MongoDBURL"]

var option = {
  db:{
    numberOfRetries : 5
  },
  server: {
    auto_reconnect: true,
    poolSize : 40,
    socketOptions: {
        connectTimeoutMS: 500
    }
  },
  replSet: {},
  mongos: {}
};

function MongoPool(){}

var p_db;

function initPool(cb){
  MongoClient.connect(url, option, function(err, db) {
    if (err) throw err;

    p_db = db;
    if(cb && typeof(cb) == 'function')
        cb(p_db);
  });
  return MongoPool;
}

MongoPool.initPool = initPool;

function getInstance(cb){
  if(!p_db){
    initPool(cb)
  }
  else{
    if(cb && typeof(cb) == 'function')
      cb(p_db);
  }
}
MongoPool.getInstance = getInstance;

module.exports = MongoPool;

启动服务器时，调用initPool

require("mongo-pool").initPool();

然后在任何其他模块，你可以这样做:

var MongoPool = require("mongo-pool");
MongoPool.getInstance(function (db){
    // Query your MongoDB database.
});

这是基于MongoDB文档的。看一看。

如果你有Express.js，你可以使用express- MongoDB -db在请求之间缓存和共享MongoDB连接，而不需要一个池(因为接受的答案说这是共享连接的正确方式)。

如果没有，你可以查看它的源代码并在另一个框架中使用它。