Since the portlets are all different from the servlet, they should pay attention to the following issues when writing a portlet application:
Servlet is independent of the performance layer, so a complete web application can have only one servlet as a Controller. However, portlets are related to the performance layer, and multiple portlets of the performance layer will correspond to multiple Concrete portlets.
For web applications, we can divide the processing process of the operational request into two steps, processing requests, and display results. In traditional servlet / jsp applications, requests and demonstrations are always performed together. However, in the portlet application, the situation has changed: When Doview or Doedit is called, only the part is called. This causes the processing and showing the execution frequency of the portlet application and the two-stage processing mode of the portlet application.
URLs in portlet are dynamically generated (portlets provide an API to complete).
Portlet does not support Forward and Redirect.
