PageContext, request, session, and application differences

Pagecontext,request,session,application refers to the life cycle of variables (objects) that can be set or read by SetAttribute () and getattribute ().

The scope of the PageContext object applies only to the current page range, which means that more than this page can be used. Therefore, it is not possible to use the PageContext object to pass parameters to other pages.

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

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

The scope of the application executes the service at the beginning of the server, until the server shuts down. It has the largest range and the longest life cycle.

PageContext, request, session, and application differences