// 引入mongoose模块
const mongoose = require('mongoose');
// 链接数据库
mongoose.set('useCreateIndex', true) //加上这个
mongoose.connect('mongodb://localhost/xxxxxxxxx',{useNewUrlParser: true,useUnifiedTopology: true})
.then(()=>console.log('数据库连接成功'))
.catch(()=>console.log('数据库连接失败'))