如何用Nodemon连接Mongoose？遇ECONNREFUSED错误求助

问题详情 #

我正在学习MongoDB，按照教程步骤通过Mongoose连接数据库，运行nodemon时出现连接错误，已确认MongoDB服务器处于运行状态。

错误日志 #

PS C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend> nodemon .\index.js       
[nodemon] 3.0.1
[nodemon] to restart at any time, enter `rs`
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,cjs,json
[nodemon] starting `node .\index.js`
Connected to Mongo Successfully
C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend\node_modules\mongoose\lib\connection.js:788
    err = new ServerSelectionError();
          ^

MongooseServerSelectionError: connect ECONNREFUSED ::1:27017
    at _handleConnectionErrors (C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend\node_modules\mongoose\lib\connection.js:788:11)
    at NativeConnection.openUri (C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend\node_modules\mongoose\lib\connection.js:763:11) {
  reason: TopologyDescription {
    type: 'Unknown',
    servers: Map(1) {
      'localhost:27017' => ServerDescription {
        address: 'localhost:27017',
        type: 'Unknown',
        hosts: [],
        passives: [],
        arbiters: [],
        tags: {},
        minWireVersion: 0,
        maxWireVersion: 0,
        roundTripTime: -1,
        lastUpdateTime: 5093783,
        lastWriteDate: 0,
        error: MongoNetworkError: connect ECONNREFUSED ::1:27017
            at connectionFailureError (C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend\node_modules\mongodb\lib\cmap\connect.js:367:20)
            at Socket.<anonymous> (C:\Users\KIIT\OneDrive\Desktop\MERN\Web Development\Inotebook\inotebook_backend\node_modules\mongodb\lib\cmap\connect.js:290:22)
            at Object.onceWrapper (node:events:628:26)
            at Socket.emit (node:events:513:28)
            at emitErrorNT (node:internal/streams/destroy:151:8)
            at emitErrorCloseNT (node:internal/streams/destroy:116:3)
            at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {
          cause: Error: connect ECONNREFUSED ::1:27017
              at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1494:16) {
            errno: -4078,
            code: 'ECONNREFUSED',
            syscall: 'connect',
            address: '::1',
            port: 27017
          },
          [Symbol(errorLabels)]: Set(1) { 'ResetPool' }
        },
        topologyVersion: null,
        setName: null,
        setVersion: null,
        electionId: null,
        logicalSessionTimeoutMinutes: null,
        primary: null,
        me: null,
        '$clusterTime': null
      }
    },
    stale: false,
    compatible: true,
    heartbeatFrequencyMS: 10000,
    localThresholdMS: 15,
    setName: null,
    maxElectionId: null,
    maxSetVersion: null,
    commonWireVersion: 0,
    logicalSessionTimeoutMinutes: null
  },
  code: undefined
}

Node.js v18.16.1
[nodemon] app crashed - waiting for file changes before starting...

相关代码文件 #

db.js

const mongoose = require('mongoose');
const mongoURI = "mongodb://localhost:27017/"

const connectToMongo = async () => {
    mongoose.connect(mongoURI);
    console.log("Connected to Mongo Successfully");
}

module.exports = connectToMongo

index.js

const connectToMongo = require('./db')
connectToMongo();

解决方案 #

1. 修复异步连接逻辑

你的connectToMongo声明为async函数，但未使用await处理mongoose.connect的异步操作，导致连接未完成就提前打印成功信息，同时没有错误捕获机制。修改db.js：

const mongoose = require('mongoose');
// 替换localhost为127.0.0.1，强制使用IPv4；同时指定目标数据库名（如inotebook）
const mongoURI = "mongodb://127.0.0.1:27017/inotebook"

const connectToMongo = async () => {
    try {
        await mongoose.connect(mongoURI);
        console.log("Connected to Mongo Successfully");
    } catch (error) {
        console.error("MongoDB连接失败:", error);
        process.exit(1); // 连接失败时终止进程，避免后续逻辑异常
    }
}

module.exports = connectToMongo

2. 解决IPv6解析问题

Node.js 18及以上版本默认优先将localhost解析为IPv6地址（::1），而多数本地MongoDB实例默认仅监听IPv4地址（127.0.0.1），导致连接被拒绝。将连接字符串中的localhost替换为127.0.0.1即可强制使用IPv4连接。

3. 验证MongoDB监听配置

检查MongoDB配置文件（Windows下通常为C:\Program Files\MongoDB\Server\版本号\bin\mongod.cfg）中的net.bindIp项，确保其值包含127.0.0.1或0.0.0.0（允许所有IP访问）。修改后需重启MongoDB服务。

4. 确认MongoDB服务状态

在命令行执行mongod命令，或通过服务管理器确认MongoDB服务正在运行；也可直接运行mongo或mongosh命令测试是否能成功进入MongoDB shell，排除服务本身的问题。

内容的提问来源于stack exchange，提问作者Sahil