UnhandledPromiseRejectionWarning: MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017

Question

我下载了mongoDB，它工作得很好，但是当我想使用REST API并在命令行中使用npm run dev时，它给了我这个错误。That's an error

(node:10100) UnhandledPromiseRejectionWarning: MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
    at NativeConnection.Connection.openUri (D:\Node Js\task-manager\node_modules\mongoose\lib\connection.js:800:32)
    at D:\Node Js\task-manager\node_modules\mongoose\lib\index.js:341:10
    at D:\Node Js\task-manager\node_modules\mongoose\lib\helpers\promiseOrCallback.js:31:5
    at new Promise (<anonymous>)
    at promiseOrCallback (D:\Node Js\task-manager\node_modules\mongoose\lib\helpers\promiseOrCallback.js:30:10)
    at Mongoose.connect (D:\Node Js\task-manager\node_modules\mongoose\lib\index.js:340:10)
    at Object.<anonymous> (D:\Node Js\task-manager\src\db\mongoose.js:3:10)
    at Module._compile (internal/modules/cjs/loader.js:1137:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1157:10)
    at Module.load (internal/modules/cjs/loader.js:985:32)
    at Function.Module._load (internal/modules/cjs/loader.js:878:14)
    at Module.require (internal/modules/cjs/loader.js:1025:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at Object.<anonymous> (D:\Node Js\task-manager\src\index.js:2:1)
    at Module._compile (internal/modules/cjs/loader.js:1137:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1157:10)
(node:10100) 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:10100) [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.

在此之前，当我想连接数据库并投影它时，它可以工作，但现在它不工作，当我尝试连接它时，它正在停止And thats not connecting picture

Answer 1

考虑到在发出npm run dev之前MongoDB应该处于运行状态。

您必须先使用mongod命令初始化数据库引擎。有时很容易忘记这一步。

Answer 2

我认为您的URL格式不正确，

使用下面的URL

mongodb://localhost:27017/{DATABASE_NAME}

Answer 3

在我的示例中，当我将"mongodb://localhost:27017“更改为"mongodb://127.0.0.1:27017”时，它起作用了