如何在没有特定req.body的情况下将用户输入存储到MongoDB中？

const express = require('express');
const MongoClient = require('mongodb').MongoClient;

const app = express();
const url = 'mongodb://localhost:27017'; // MongoDB连接URL
const dbName = 'mydb'; // 数据库名称

app.post('/saveData', (req, res) => {
  // 获取用户输入的数据
  const userInput = req.query.data;

  // 连接到MongoDB数据库
  MongoClient.connect(url, (err, client) => {
    if (err) {
      console.error('Failed to connect to MongoDB:', err);
      res.status(500).send('Failed to connect to MongoDB');
      return;
    }

    // 选择数据库
    const db = client.db(dbName);

    // 选择集合
    const collection = db.collection('userData');

    // 将用户输入存储到MongoDB中
    collection.insertOne({ data: userInput }, (err, result) => {
      if (err) {
        console.error('Failed to insert data into MongoDB:', err);
        res.status(500).send('Failed to insert data into MongoDB');
        return;
      }

      console.log('Data saved to MongoDB:', result.ops);
      res.status(200).send('Data saved to MongoDB');
    });

    // 关闭数据库连接
    client.close();
  });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});