How to create formatted ex.sheet in java

My project needs one report which should be able to open in excel . It needs to be well formated , like first two columns fixed , left 3 col. fixed . Need to show colors in different cells (according to data) .
And I need to give a link to user to download this file. My problem is that how do I format data in csv format , so that when user open file in excel it would open in formatted form. ?