运行 npm start 后，过了一段时间，然后我在终端中收到此错误。我是新来表达 js 和 node 与 mysql 配对，所以我不能真正理解下面的错误，希望这是足够的上下文。该项目是一个简单的数据库表格内容的表格展示，效果很好，我只需要每10-40秒运行一次npm start即可。
events.js:291
throw er; // Unhandled 'error' event
^
Error: Connection lost: The server closed the connection.
at Protocol.end (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:112:13)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:94:28)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:526:10)
at Socket.emit (events.js:326:22)
at endReadableNT (_stream_readable.js:1226:12)
at processTicksAndRejections (internal/process/task_queues.js:80:21)
Emitted 'error' event on Connection instance at:
at Connection._handleProtocolError (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:423:8)
at Protocol.emit (events.js:314:20)
at Protocol._delegateError (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:398:10)
at Protocol.end (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:116:8)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:94:28)
[... lines matching original stack trace ...]
at processTicksAndRejections (internal/process/task_queues.js:80:21) {
fatal: true,
code: 'PROTOCOL_CONNECTION_LOST'
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! nodeapp@0.0.0 start: `node ./bin/www`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the nodeapp@0.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /Users/thodoristhomaidis/.npm/_logs/2021-01-22T03_09_42_711Z-debug.log
thodoristhomaidis@Theos-iMac nodeapp % npm i -g mysql
+ mysql@2.18.1
added 11 packages from 15 contributors in 0.589s
thodoristhomaidis@Theos-iMac nodeapp % npm start
> nodeapp@0.0.0 start /Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp
> node ./bin/www
Database is connected successfully !
GET /users/form 304 7.634 ms - -
GET /css/form-style.css 404 3.291 ms - 1532
events.js:291
throw er; // Unhandled 'error' event
^
Error: Connection lost: The server closed the connection.
at Protocol.end (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:112:13)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:94:28)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:526:10)
at Socket.emit (events.js:326:22)
at endReadableNT (_stream_readable.js:1226:12)
at processTicksAndRejections (internal/process/task_queues.js:80:21)
Emitted 'error' event on Connection instance at:
at Connection._handleProtocolError (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:423:8)
at Protocol.emit (events.js:314:20)
at Protocol._delegateError (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:398:10)
at Protocol.end (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/protocol/Protocol.js:116:8)
at Socket.<anonymous> (/Volumes/HDD 500GB/* Documents/2 webdev/projects/nodejs/db connection demo/nodeapp/node_modules/mysql/lib/Connection.js:94:28)
[... lines matching original stack trace ...]
at processTicksAndRejections (internal/process/task_queues.js:80:21) {
fatal: true,
code: 'PROTOCOL_CONNECTION_LOST'
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! nodeapp@0.0.0 start: `node ./bin/www`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the nodeapp@0.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /Users/thodoristhomaidis/.npm/_logs/2021-01-22T03_11_13_709Z-debug.log
答案 0 :(得分：0)
尝试使用 this code 来处理服务器断开连接：
var db_config = {
host: 'localhost',
user: 'root',
password: '',
database: 'example'
};
var connection;
function handleDisconnect() {
connection = mysql.createConnection(db_config); // Recreate the connection, since
// the old one cannot be reused.
connection.connect(function(err) { // The server is either down
if(err) { // or restarting (takes a while sometimes).
console.log('error when connecting to db:', err);
setTimeout(handleDisconnect, 2000); // We introduce a delay before attempting to reconnect,
} // to avoid a hot loop, and to allow our node script to
}); // process asynchronous requests in the meantime.
// If you're also serving http, display a 503 error.
connection.on('error', function(err) {
console.log('db error', err);
if(err.code === 'PROTOCOL_CONNECTION_LOST') { // Connection to the MySQL server is usually
handleDisconnect(); // lost due to either server restart, or a
} else { // connnection idle timeout (the wait_timeout
throw err; // server variable configures this)
}
});
}
handleDisconnect();
在您的代码中，我遗漏了 connection = mysql.createConnection(db_config);
你能检查一下this