text: var mysql = require('mysql');
  var connection = mysql.createConnection({
      host:'localhost',
      user:'root',
      password:'123456',
      database:'crawl'
  })
  //连接数据库
  connection.connect();
  exports.connection = connection;
  /*
  connection.query('select * from category',function(err,result){
      console.log(result);
  });*/
  