Struts is a java framework for web implements the MVC design pattern.
Struts facilitates the work of page redirection, form submitting, data validation and much more.

a common scenario is a login page
login.jsp that contains two inputs user name and password
a simple java class/bean that maps this information ( has two properties username and password)
an action servlet that receives the login page data and put them into the bean
then make a specific action (Logining) after that redirecting to another page (success page or return to the login page if error happened)