Apache Shiro 架构
Apache Shiro Architecture
Apache Shiro’s design goals are to simplify application security by being intuitive and easy to use. Shiro’s core design models how most people think about application security - in the context of someone (or something) interacting with an application.
Software applications are usually designed based on user stories. That is, you’ll often design user interfaces or service APIs based on how a user would (or should) interact with the software. For example, you might say, “If the user interacting with my application is logged in, I will show them a button they can click to view their account information. If they are not logged in, I will show a sign-up button.”
This example statement indicates that applications are largely written to satisfy user requirements and needs. Even if the ‘user’ is another software system and not a human being, you still write code to reflect behavior based on who (or what) is currently interacting with your software.
Shiro reflects these concepts in its own design. By matching what is already intuitive for software developers, Apache Shiro remains intuitive and easy to use in practically any application.
在最高概念性级别，Shiro 有 3 个主要概念：Subject，SecurityManager 和 Realms。下面这张图这些组件相互作用的一个概览。下面我们会讲解每个概念。
Subject：As we’ve mentioned in our Tutorial, the Subject is essentially a security specific ‘view’ of the the currently executing user. Whereas the word ‘User’ often implies a human being, a Subject can be a person, but it could also represent a 3rd-party service, daemon account, cron job, or anything similar - basically anything that is currently interacting with the software.
Subject instances are all bound to (and require) a SecurityManager. When you interact with a Subject, those interactions translate to subject-specific interactions with the SecurityManager.