nodejs使用MYSQL连接池，断线重连

两种方式解决
1、你可以配置mysql的连接池

var mysql = require(‘mysql‘);
var pool = mysql.createPool({
    host: ‘localhost‘,
    user: ‘nodejs‘,
    password: ‘nodejs‘,
    database: ‘nodejs‘,
    port: 3306
});

var selectSQL = ‘select * from t_user limit 10‘;

pool.getConnection(function (err, conn) {
    if (err) console.log("POOL ==> " + err);

    conn.query(selectSQL,function(err,rows){
        if (err) console.log(err);
        console.log("SELECT ==> ");
        for (var i in rows) {
            console.log(rows[i]);
        }
        conn.release();
    });
});

2、你可以使用断线重连的方式来解决

var mysql = require(‘mysql‘);
var conn;
function handleError () {
    conn = mysql.createConnection({
        host: ‘localhost‘,
        user: ‘nodejs‘,
        password: ‘nodejs‘,
        database: ‘nodejs‘,
        port: 3306
    });

    //连接错误，2秒重试
    conn.connect(function (err) {
        if (err) {
            console.log(‘error when connecting to db:‘, err);
            setTimeout(handleError , 2000);
        }
    });

    conn.on(‘error‘, function (err) {
        console.log(‘db error‘, err);
        // 如果是连接断开，自动重新连接
        if (err.code === ‘PROTOCOL_CONNECTION_LOST‘) {
            handleError();
        } else {
            throw err;
        }
    });
}
handleError();