Java - when do we need to use spring Framework and when do we need to use Struct2 framework .

Hi All,
           I want to know when to use a spring Framework to develope a web Application and when to use a Struct2 Framework to develope a web Applications.

i find it easier to use struct2 Framework for web application and spring for windows Applications.

Please correct me to know when to always use Spring Framework and when to Use Struct Framework in developing a Java Applications.

This confuses me a lot.

Thanks