Java Common Interface Rollup

Servlet Common Interface:

1, the servlet implementation Related:

(1) Servlet interface: Primarily defines the lifecycle method of the servlet, which defines the following methods:

L init (servletconfig config) is used to initialize the servlet

L Destroy () destroy Servlet

L Getservletinfo () Get information about the servlet

L Getservletconfig () obtain servlet configuration-related information

L Service (ServletRequest req, servletresponse Res) runs the application's logical entry point. ServletRequest represents the client's request information; Servletresponse represents the response to the client.

(2) Genericservlet abstract class: Provides a general implementation of the servlet (including the implementation of the servlet and ServletConfig two interfaces), An important object of a servletconfig type that the container passes through the Init method to the servlet is saved.

(3) HttpServlet abstract class: Provides a general implementation for the servlet that handles HTTP requests, primarily defining and implementing several service methods. The HttpServlet subclass must implement one of the following methods:

L doget ()

L DoPost ()

L DoPut ()

L Dodelete ()

L init () and Destroy ()

L Getservletinfo ()

2, servlet configuration Related:

(4) ServletConfig interface: Provides a servlet with a number of important objects and methods for using container services. The main methods are as follows:

L Getinitparameter (String name) returns the initialization parameters for a particular name.

L Getinitparameternames () returns the name of all initialization parameters

L Getservletcontext () returns a reference to the context object of the servlet.

3, Servlet context-Related:

(5) ServletContext interface: Is the context object of the servlet, which was created at server startup and provides the servlet with several important methods for using container services. It's commonly used methods:

L getattribute (String name) gets the property named name in ServletContext

L GetContext (String Uripath) Returns the context of the servlet for the given Uripath application

L removeattribute (String name) deletes a property with name

L setattribute (String Name,object object) sets a property in ServletContext, the name of the property, and the value is object.

4. Request and Response related

There are a number of interfaces and classes associated with requests and responses, mainly several:

(6) ServletRequest: Represents the request of the servlet. It's a high-level interface, and HttpServletRequest is its sub-interface.

(7) Servletresponse: Represents the response of the servlet. It's a high-level interface, and HttpServletResponse is its sub-interface.

(8) Servletinputstream:servlet input stream

(9) output stream of Servletoutputstream:servlet

(a) Servletrequestwrapper: the realization of ServletRequest

(one) Servletresponsewrapper: the realization of Servletresponse

(in) HttpServletRequest: represents HTTP request

(HttpServletResponse): Represents the response of HTTP

Implementation of (Httpservletrequestwrapper:httpservletrequest)

(a) Httpservletresponsewrapper:httpservletresponse implementation

5. Session Tracking

(HttpSession)

6. servlet Collaboration

(RequestDispatcher)

7, Filtration

(km) Filter

(Filterchain)

(Filterconfig)

Inheritance relationship: Genericservlet inherits the servlet and ServletConfig interfaces; HttpServlet inherits Genericservlet; The servlet we wrote Inherits HttpServlet.