Save my temperature data log to CSV file

I have an openhab on raspberry pi ( Jessie) and it read a temperature from ESP8266 throuqh mqtt
so now I want to save this temperature in a CSV files

here is my item file

Group All

Group gGroundFloor (All)

Group GF_Living "Living Room" <video> (gGroundFloor)

Number TestTemperature "Temperature [%.1f C]" <temperature> (GF_Living) {mqtt="<[MQTTSVR:/temperature1:state:default]"}

and here is my sitemap

sitemap default label="Main Menu"
        Frame label="MQTT Test" {
                Text item=TestTemperature

i read about changing logging persistence ,rule, or rrd4j persistence , but i didn’t understand well what should i do
also the events.log is shown the temperature very good

If you really want a CSV file, look at the Logging Persistence addon. This will save any update or change to your designated Items to a text file. It uses LogBack so you can specify a CVS format in the config. The only gotcha is the first row may not be column labels.

If what you really want is to just save and chart the data, you can use rrd4j, db4o, MySQL, etc to save the values and the Chart element on your sitemap to show a simple line graph of the values over time.