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我是 node.js 的新手。我只想知道在node.js中可以重新连接数据库(mysql)吗?

我编写了以下代码来在数据库关闭几分之一秒时建立连接:

var http = require("http");
var mysql = require('mysql');
var trn_nbr="";
var amount1=""; 
var db_config = {
    host : 'localhost',
    user : 'root',
    password : '',
    database: 'realmoney'
};

var connection;

function handleDisconnect() {  
  connection = mysql.createConnection(db_config); 
  connection.connect(function(err) 
  {                                                             
    if(err) 
    {                                                           
      console.log('error when connecting to db:', err);
      //setTimeout(handleDisconnect, 10000); 
      handleDisconnect();                     
    } 
    else
    { 
        console.log("Now Connected");
        connection = mysql.createConnection(db_config);
        for (var i=0; i<1000; i++)
        {  
            connection.query("select tran_nbr,tran_amount from tranlog",  function(err, rows)
            { 
                if(err) 
                {
                    if (err.code !== "PROTOCOL_CONNECTION_LOST")
                        throw err;
                    else
                    {
                        console.log('query error when connecting to db:', err);
                        //setTimeout(handleDisconnect, 10000); 
                        handleDisconnect();
                    }                               
                }
                else
                {
                    tran_nbr = rows[0].tran_nbr;
                    amount1 = rows[0].tran_amount;
                    console.log("tran_nbr:",tran_nbr);
                    console.log("Amount:",amount1);
                    //sleep.sleep(5);//sleep for 5 seconds
                }
            })           
        }
    }                                                        
  });                                                           

  connection.on('error', function(err) {
    console.log('db error', err);
    if(err.code === 'PROTOCOL_CONNECTION_LOST')
    { 
      handleDisconnect();                        
    } 
    else 
    {                                      
      throw err;                                  
    }
  });
}

handleDisconnect();

您还可以告诉我代码中的错误以帮助我。

我使用以下代码来实现连接池,但这段代码不起作用:

var mysql = require('mysql');
var pool  = mysql.createPool({
    host : 'localhost',
    user : 'root',
    password : '',
    database: 'realmoney'
});

exports.getUsers = function(callback) {
  pool.getConnection(function(err, connection) {
    if(err) { console.log(err); callback(true); return; }
    var sql = "SELECT id,name FROM users";
    connection.query(sql, [], function(err, results) {
      connection.release(); // always put connection back in pool after last query
      if(err) { console.log(err); callback(true); return; }
      callback(false, results);
    });
  });
});

我已经在我的服务器上安装了连接池模块。我在 Linux 服务器上运行 node.js 代码。我可以在 mysql 数据库关闭几秒钟后再重新连接时重新连接它,而无需重新启动 node.js 中的应用程序吗

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0 回答 0