app.conf:

appname = gowebProject
httpport = 8080
runmode = dev
copyrequestbody = true

[db]
host= localhost
port= 3306
databaseName = test
userName= root
password= root

envRar = ${XXX_XXXXX}    //XXX_XXXXX 是环境变量

pwd := beego.AppConfig.String("db::password")

envVar:=beego.AppConfig.String("db::envRar"))