這是請求的方法

app.get('/api/:id', function (req, res) {
    connection.connect();
    connection.query('SELECT * from testmodel_url WhERE id='+req.params.id, function(err, rows, fields) {
        if (err) throw err;
        let obj={
            'status':200,
            'message':'success',
            'data':rows
        }
        res.json(obj)
    });
    connection.end();
});

使用postman第一次請求可以獲得正確的結(jié)果

再次請求就會(huì)報(bào)錯(cuò)

events.js:182
      throw er; // Unhandled 'error' event
      ^

Error: Cannot enqueue Handshake after invoking quit.
    at Protocol._validateEnqueue (C:\bin\pro\express\node_modules\_mysql@2.15.0@
mysql\lib\protocol\Protocol.js:204:16)
    at Protocol._enqueue (C:\bin\pro\express\node_modules\_mysql@2.15.0@mysql\li
b\protocol\Protocol.js:139:13)
    at Protocol.handshake (C:\bin\pro\express\node_modules\_mysql@2.15.0@mysql\l
ib\protocol\Protocol.js:52:23)
    at Connection.connect (C:\bin\pro\express\node_modules\_mysql@2.15.0@mysql\l
ib\Connection.js:130:18)
    at C:\bin\pro\express\index.js:29:16
    at Layer.handle [as handle_request] (C:\bin\pro\express\node_modules\_expres
s@4.16.3@express\lib\router\layer.js:95:5)
    at next (C:\bin\pro\express\node_modules\_express@4.16.3@express\lib\router\
route.js:137:13)
    at Route.dispatch (C:\bin\pro\express\node_modules\_express@4.16.3@express\l
ib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\bin\pro\express\node_modules\_expres
s@4.16.3@express\lib\router\layer.js:95:5)
    at C:\bin\pro\express\node_modules\_express@4.16.3@express\lib\router\index.
js:281:22

這是為什么呢求解答 0.0