Approved: Fortect
Last week, some of our readers came across a bug with the Servlet Container Model. This problem can arise for several reasons. Let’s discuss it now.
This is Chapter 4: The Servlet Container Model from the Sun Certification Training Guide (310-080): Java 2 Enterprise Edition (J2EE) Web Component Developer (ISBN: 0-7897-2821-4) Alain von Trottier, published by Qué.
Chapter 4. The Servlet Container Model
Goals
This chapter covers the following tasks that Sun discovered in “Section 1 – Servlet Model” and “Section 3 – Servlet Container Model”.
1.1. Define the appropriate
for each of the HTTP GET, POST, and PUT methods. The solution is in the HttpServlet class.
HTTP GET , POST and PUT links are browsers
And the web servers exchange the purpose of communication. Just GET
wants to get an absolute page without providing a lot of information. POST ,
however, it can package a whole bunch of forms or information files on its own. A
PUT actually downloads the file. The refinement HttpServlet has
the corresponding secret for each HTTP method, including doGet () , doPost () ,
and doPut () .
1.2. Define triggers for each of the HTTP GET, POST and HEAD methods
which may prompt the browser to use our method and identify advantages or features
based on the le.
Here you will be asked to understand the events associated with each type
request; for example if you move a hyperlink a GET request is sent
to your web hosting company, but click the submit button (if the action is set to "publish" )
sends a POST request.
1.3. Specify an interface and method for each of the following operations
indicate who you should get used to
- Get parameters of the HTML request type.
- The socket servlet initialization parameter.
- Get information about HTTP request headers.
- Put the HTTP response header; specify response content type
- Get good text for your reply.
- Get a specific bitstream for a response.
- Redirect 1 HTTP request to another URL.
This goal can be overwhelming. It covers the core of the new servlet process,
in particular the response to the request and objects. Request settings for
. TO servlet are strings that the client has connected to the servlet container.
Seeder takedrops a scan request and puts policies and information into
An object that is no doubt passed to the servlet. Most containers go in the opposite direction
wraps response parameters in a HttpServletResponse object,
which is returned to the container. Relevant section of a step later
For more information, see this chapter (“Replace HttpServlet GET , POST ,
then PUT Methods “) describes your methods in detail.
1.4. Define an interface in addition to the method of accessing and evaluating equipment and
to define object attributes in the following three web areas:
- Request
- session
- context
This goal is related to the idea of volume. When something has context
The scope is vast, and virtually any user can exchange data. Conference room
means a dieter can share data across multiple page views, but other users cannot.
The scope of requirements completely restricts the data on this page.
1.5 For a given lifecycle platform, definecorrect ads for its purpose
more about how when he was called. These methods
- initialize
- Services
- Destroy the bottle
Manages the lifecycle of a servlet. This Chapter Ingredient
uses examples to explain how the launcher initializes servlet a with
Calling the current init () method. Then it calls the () service
Any method upon request. Finally, if the servlet needs to be removed
The container calls the destroy () method from memory. This gives
the servlet has one last chance to clean up resources.
1.6 Use a good, reliable RequestDispatcher to enable or load it for authorization on a web resource.
The requestdispatcher object is the servlet dispatch mechanism.
You will probably see how to do streaming in the Servlet Life Cycle
Request transaction from one servlet directly to another (which browser
Without realizing). This way the servlet can pass the request to another website
An item in the same web container.
3.1. Determine the use interface classes) (or methods for
performs the following functions:
- Servlet context initialization parameters
- Servlet Context Listener
- Servlet Context Attribute Listener
- session attribute listener
These elements can be called as attributes of the monitoring servlet. Maybe not only
You get men and women and change them too, but you can actually introduce behavior
occur when an attribute is changed. Listeners are driven by events.
In case of great attribute changes, specific methods are flagged. In them
You can set special actions, for example, add one note to the journal at a time
which changes the number of users (perhaps an attribute situation called a counter).
3.3 In the redistributable file, distinguish the behavior from the following:
- Servlet perspective initialization parameters
- Servlet Context Listener
- Servlet context highlighting listener
- session attribute listener
As explained in the previous task type, these elementsnts allow you to create and
Machine servlet attributes. There is a corresponding difference here that Sun wants
to understand how this works in a redistributable web application.
Map
GET
Approved: Fortect
Fortect is the world's most popular and effective PC repair tool. It is trusted by millions of people to keep their systems running fast, smooth, and error-free. With its simple user interface and powerful scanning engine, Fortect quickly finds and fixes a broad range of Windows problems - from system instability and security issues to memory management and performance bottlenecks.
POSTER
DELIVER
GET
POSTER
HEAD
Form parameters
Get HTTP Parameter for Servlet Initialization
Get information from the request header
Capture a binary stream for response
Redirect HTTP request to another URL
Request
session
Context
The main secret of this section of the exam is to understand how servlets, in general, implement servlet work, which defines lifecycle methods. A servlet container (like Apache Tomcat) is a special application that monitors a port at a fully specified IP address. Servlets generate responses to HTTP requests. To do this, the bucket loads your servlet (if it doesn’t already use memory) and calls the methods described in the interface. This is arThe Foundation Servlet Heitecture and Connected JSP.
There are several known methods. Thematically, the methods are easier to learn in a group. For example, an assembly servlet with HttpServlet methods that handle three types of requests: GET , POST , and PUT .
Each JavaServer page is converted into a nice servlet that is compiled and then built. Hence, many
Speed up your computer's performance now with this simple download.
The servlet container invokes the methods of the servlet as well as services that the servlet not only needs to start. The servlet container is usually registered in Java and is part of the web server (if the remote web machine is also written in Java) or is always linked and used by an absolute web server.
The servlet container usually provides easy servlet access to the properties of your current HTTP request, such as its headers and parameters. When the servlet is synchronizing (for example, when a servlet is specified in the url), the web server forwards the HTTP request to the servlet container. The pan, in turn, forwards the request to your current servlet.
When a servlet is received, the web hosting server forwards the request to the web container. The web container is responsible for instantiating the actual servlet or creating a new thread to ensure that the request is processed. The container provides multiple threads to handle multiple requests for a single servlet.
