~~~ const MongoClient = require('mongodb').MongoClient; var url = 'mongodb://localhost:27017/'; console.time('start') MongoClient.connect(url, { useNewUrlParser: true },(err,client)=>{ if(err) throw err; var db = client.db('my-test'); db.collection('user').find({}).toArray((err,data)=>{ if(err) throw err; console.log(data); console.timeEnd('start') }) }) //耗时将近一秒 ~~~