var mysql=require("mysql");
exports.connect=function(sql,param,callback){
  var db=mysql.createConnection({
    host:"localhost",   ///数据库URL
    port:"3306",     //数据库端口，默认3306
    user:"root", 
    password:"root",
    database:"databaseName"
  });
  db.connect();
  db.query(sql,param,callback);
  db.end();
};

var db=require("./routes/db.js");
app.get("/index.html",function(req,res){
  db.connect("select * from t_user",function(error,data){
    console.log(data);
  });
  res.send("<h1>success</h1>");
});