OCEJWCD - 4.The Servlet's environment (part1)

OCEJWCD (SCWCD) - 1Z0-899 - Web Component Developer Certification

4.1. Understand more details of the HTTP protocol

HTTP protocol is used to transfer resources between a client and a server. 
HTTP is stateless.

The information is identified by URL (uniform resource locator).
URL structure: protocol://machine:port/context/resource

Methods in HTTP

• HEAD : get metainfo contained in headers
• GET : get a resource from the server
• POST : send data included in the body to the server to be processed (get,add or update)
• PUT :  send a resource(file) to the server by a new connection.
• DELETE: delete a resource
• TRACE : to obtain a response code from the server
• OPTIONS : to obtain http methods supported
• CONNECT : to transform connection to https
• PATCH : to modify partially a resource in the server.

Response codes in HTTP

The most common are:

• 4XX - Error in client side
• 5XX - Error in server

4.2. Understand fundamentals of HTML forms

A html form has these attributes:

- action :  resource

- method : GET or POST

• GET : add form data to the URL using ? as separator (QueryString)
• POST : the data is sent into the body.

The above form contains these different elements:

• Textfield
• Radiobutton
• Checkbox
• Buttons
• SelectionList
• TextArea

When the submit button is clicked the form-data is sent to a page on the server called "order.jsp"

See next post The Servlet's Environment (part2)

OCEJWCD (SCWCD) - 1Z0-899 - Web Component Developer Certification