Four scope size __JS for JSP

Request is an object that encapsulates the requested data and attributes submitted by the client side (that is, the user through browser).
response are objects that encapsulate Web server-side response data and attributes.

pagecontext,request,session,application refers to the life cycle of a variable (object).
We often confuse PageContext, request, session, and application as they can be set or read by SetAttribute () and getattribute (). But there is something else between them, and their biggest difference is in the scope of use. The

scope of the PageContext object applies only to the current page range, which is not available beyond this page. So it is not possible to use the PageContext object to pass parameters to other pages. The

scope of the request object refers to a JSP Web page that makes a request to another JSP Web page, and then this property is invalidated. The session is

scoped to a period of time that the user continues to connect to the server, but this property is invalid when disconnected from the server. such as breaking the Web or closing the browser. The

scope of the application is performed at the beginning of the server, until the server is shut down. It has the largest range and the longest life cycle.