Node.js+MongoDB开发：Postman请求无响应API失效问题

我是Node.js和Postman的新手，尝试运行CRUD操作时遇到问题：Postman一直显示“发送请求”，无法获取响应。数据库已成功连接，但API似乎无法正常工作。根路径的app.get接口可正常响应，不过通过app.use挂载的/location路由接口无响应。

Postman请求端点：GET http://localhost:7400/location

主文件代码 #

const express=require('express');
const bodyParser=require('body-parser');
const mongoose=require('mongoose');

const locRoute=require("./routes/location");

mongoose.set('strictQuery', true)
const app=express();
const PORT=7400;

const MONGO_URI="mongodb://localhost:27017/myrough";

mongoose.connect(MONGO_URI,()=>{
    console.log('connected to db');
},e=>console.log("Error",e));

app.use(bodyParser.json());

app.use('/location', locRoute);    
app.get('/',(req,res)=>res.send('working'))

app.listen(PORT,()=>{
    console.log(`Server is running on port ${PORT}`);
})

Location路由代码 #

const express=require('express');
const locationController=require('../Controllers/location')

const routes=express.Router();
console.log('menu')
routes.get('/',locationController.getLocations);

module.exports=routes;

Location控制器代码 #

const locations=require('../Models/location');

exports.getLocations=(req,res)=>{
    locations.find().then(result=>{
        res.status(200).json({
            message:"locations successfully fetched from DB",
            data:result
        })
    }).catch(error=>{
        res.status(500).json({
            message:"locations not found",
            error:error
        })
    });
}

Location模型代码 #

const mongoose=require('mongoose');

const locationSchema= mongoose.Schema({
    name:{
        type:String,
        required:true
    },
    city_id:{
        type:String,
        required:true
    },
    location_id:{
        type:String,
        required:true
    },
    country_name:{
        type:String,
        required:true
    }
});

module.exports=mongoose.model("Locations",locationSchema,"locations");

MongoDB数据 #

{
  "_id": "1",
  "name": "ShalimarBhagh, Delhi",
  "city_id": "1",
  "location_id": "1",
  "country_name": "India"
},
{
  "_id": "2",
  "name": "Janpat, Delhi",
  "city_id": "1",
  "location_id": "2",
  "country_name": "India"
}

问题排查与解决方法 #

1. 修正MongoDB _id类型不匹配问题 #

你的MongoDB数据中_id是字符串类型，但Mongoose默认将_id视为ObjectId类型。执行find()时，Mongoose会尝试将字符串_id转换为ObjectId，导致查询卡住无响应。

解决：在Schema中显式指定_id为String类型：

const locationSchema= mongoose.Schema({
    _id: { type: String, required: true }, // 新增该行
    name:{ type:String, required:true },
    city_id:{ type:String, required:true },
    location_id:{ type:String, required:true },
    country_name:{ type:String, required:true }
});

2. 完善数据库连接逻辑 #

当前代码在数据库未完全连接时就启动了服务器，可能导致请求时数据库连接未就绪。改用Promise链式调用，确保连接成功后再启动服务：

mongoose.set('strictQuery', true)
const app=express();
const PORT=7400;
const MONGO_URI="mongodb://localhost:27017/myrough";

mongoose.connect(MONGO_URI)
  .then(() => {
      console.log('connected to db');
      app.listen(PORT,()=>{
          console.log(`Server is running on port ${PORT}`);
      });
  })
  .catch(e => console.log("DB Connection Error",e));

3. 添加日志排查请求流程 #

在控制器中添加日志，确认请求是否进入查询逻辑、是否返回结果：

exports.getLocations=(req,res)=>{
    console.log("收到/location GET请求");
    locations.find().then(result=>{
        console.log("查询结果：", result);
        res.status(200).json({
            message:"locations successfully fetched from DB",
            data:result
        })
    }).catch(error=>{
        console.log("查询错误：", error.message);
        res.status(500).json({
            message:"locations not found",
            error:error.message
        })
    });
}

4. 验证Postman请求配置 #

确保Postman发送的是GET请求，地址为http://localhost:7400/location，未添加多余的Headers或参数导致请求异常。

内容的提问来源于stack exchange，提问作者5B8-Sujith