****专科毕业设计（专业外文翻译）
OpenID for Java Web applications
Summary: OpenID is a decentralized authentication protocol that makes it easier for users
to access resources in your Java™ Web applications. In this first half of a two-part article,
you'll learn about the OpenID Authentication Specification and walk through the steps of
incorporating it into a sample Java application. Rather than implement the OpenID
Authentication specification by hand, author J. Steven Perry uses the openid4java library
and a popular OpenID provider, myOpenID, to create a safe and reliable registration
process for a Java application written in Wicket.
Tags for this article: authentication, java, openid, openid4java, sign-on, single,
steve_perry, webs
OpenID is a decentralized authentication mechanism. Using OpenID, I can prove I
own a URI such as http://openid.jstevenperry.com/steve, and I can use that identity to
authenticate myself with any site that supports OpenID — such as Google, Slashdot, or
Wordpress. Clearly, Open ID is great for end users. But using it got me to thinking: "What
about using OpenID to create a standard, reliable authentication system for the Java-based
Web applications I write for my customers?"
In this two-part article I will show you how to use the openid4java library and a well-
known OpenID provider, myOpenID, to create an authentication system for a Java-based
Web application. I'll also show you how to receive user information with an OpenID
Simple Registration Extension (SReg).
I'll start by explaining what OpenID is and showing you how to get an OpenID of your
own. Next, I will present a brief overview of how OpenID authentication works. Finally, I
will walk through the steps involved in performing OpenID authentication using
openid4java. In the second half of this article, you'll learn how to create your own OpenID
provider.
Throughout the discussion I'll be working with a Wicket-based Java Web application
that I wrote specifically for this article. You can download the source code for the
application any time. You also might want to take a look at the openid4java library (see
Resources).
Note: This article focuses on using OpenID for Java Web applications, but OpenID
works in any software architectural scenario.
Introduction to OpenID
OpenID is a specification for proving a user owns an identifier. For now, just think of
an identifier as a String that uniquely identifies a user. If you're like me, you own many
identifiers or userids. I have a userid at Facebook, another at Twitter, and others at dozens
of sites that I use around the Internet. I always try to use the same userid but it's not
available on every new site I sign up for. So, I have a mental map of all of my userids and
the Web sites they're associated with. What a pain; I use the "Forget your password?"
feature a lot! It would be great if there were a way to claim a single identifier and use it
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