February 2014
Intermediate to advanced
384 pages
9h 8m
English
Content preview from Java Programming Interviews Exposed
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Chapter 14
Using HTTP and REST
HTTP is one of the core ways for requesting and receiving data over the Internet. It is used for communication over the World Wide Web. HTTP servers, such as Apache’s HTTPD, Microsoft’s IIS, and Tomcat, are configured to listen for structured incoming requests, and respond appropriately.
The HTTP Methods
What is HTTP?
A good exercise in understanding how the HTTP protocol works is to perform an HTTP request outside of a browser using an application such as Telnet which is provided with most modern operating systems.
To make a request to a site, such as Wikipedia, open a Telnet connection to port 80. You should see output similar to Listing 14-1.
Listing 14-1: Initiating an HTTP request using Telnet
> telnet en.wikipedia.org 80
Trying 91.198.174.225...
Connected to wikipedia-lb.esams.wikimedia.org.
Escape character is '^]'.Your command prompt should be on a blank new line. The server hosting your request is now waiting for you to make your request for a certain page. Type GET / HTTP/1.1, followed by new lines. Your Telnet session should respond with a set of HTTP headers, followed by some HTML, and will then close the connection and take you back to the command line, like in Listing 14-2.
Listing 14-2: Creating an HTTP request using Telnet
GET / HTTP/1.1 HTTP/1.0 200 OK Server: Apache X-Content-Type-Options: nosniff Cache-Control: s-maxage=3600, must-revalidate, max-age=0 Last-Modified: Mon, 13 May 2013 17:07:15 GMT Vary: Accept-Encoding Content-Length: ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.