作为我课程的一部分,我正在学习MongoDB,现在是Mongoose。我已经完全按照课程中的方法编写了代码,但是当尝试用node app.js
启动它时,我得到了以下错误:
node app.js
输出量:
(node:25772) ` **UnhandledPromiseRejectionWarning: MongoNotConnectedError: MongoClient must be connected to perform this operation**
`at Object.getTopology (C:\Users\donal\OneDrive\Desktop\Udemy Web Development\FruitsProject\node_modules\mongoose\node_modules\mongodb\lib\utils.js:391:11)
at Collection.insertOne (C:\Users\donal\OneDrive\Desktop\Udemy Web Development\FruitsProject\node_modules\mongoose\node_modules\mongodb\lib\collection.js:150:61)
at NativeCollection.<computed> [as insertOne] (C:\Users\donal\OneDrive\Desktop\Udemy Web Development\FruitsProject\node_modules\mongoose\lib\drivers\node-mongodb-native\collection.js:200:33)
at NativeCollection.Collection.doQueue (C:\Users\donal\OneDrive\Desktop\Udemy Web Development\FruitsProject\node_modules\mongoose\lib\collection.js:135:23)
at C:\Users\donal\OneDrive\Desktop\Udemy Web Development\FruitsProject\node_modules\mongoose\lib\collection.js:82:24
at processTicksAndRejections (internal/process/task_queues.js:77:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:25772) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:25772) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
我在终端的一个单独的标签中运行了 mongosh,我已经尝试了几次搜索来寻找类似的问题。我该如何解决?
下面是我的 app.js 代码:
const mongoose = require("mongoose");
mongoose.connect("mongodb://localhost:27017/fruitsDB");
const fruitSchema = new mongoose.Schema({
name: String,
rating: Number,
review: String
});
const Fruit = mongoose.model("Fruit", fruitSchema);
const fruit = new Fruit({
name: "Apple",
rating: 7,
review: "Pretty solid as a fruit"
});
fruit.save();
mongoose.connection.close();
const findDocuments = function(db, callback) {
const collection = db.collection('fruits');
collection.find({}).toArray(function(err, fruits) {
assert.equal(err, null);
console.log("Found the following records");
console.log(fruits)
callback(fruits);
});
}
2条答案
按热度按时间xbp102n01#
我遇到了同样的问题,罪魁祸首是在JavaScript代码体中调用
mongoose.connection.close();
。正如AnanthDev提到的,mongoose是异步的,在它能够执行操作之前就关闭了连接。下面的工作原理是因为
mongoose.connection.close()
是在一个回调函数中,并且在操作执行之后才运行。wtzytmuj2#
mongoose.connect
是xdc,所以您尝试在与数据库建立连接之前执行代码。现在,您可以使用. wait/await或.then()来等待连接建立