Shiro —— 从一个简单的例子开始

一、Shiro是用来做权限的。

二、权限

1.基本概念：

（1）安全实体：要保护的数据。

（2）权限：是否有能力去操作（查看、修改、删除 ）保护的数据。

2、权限的两个特性

（1）权限的继承性：A 包含 B，B无权限，但A有权限，此时B 的权限即为 A 的权限。如大厦里有公共厕所，进出大厦需要门禁，所以公共厕所的权限就是大厦的门禁权限。

（2）最近路劲匹配：如大厦某层有卫生间，要想到此卫生间需要有该层电梯权限，此时该卫生间的权限为该层电梯的权限，而不是大厦的门禁权限。

3.几个关键词

（1）认证：验证用户身份，即验证登录的用户名密码是否正确，用户是否被锁死。

（2）授权：决定是否有权限访问受保护的资源。

（3）加密：保护或隐藏受保护的资源。

（4）会话管理

（5）单点登录（SSO）

三、Shiro

1.核心组件

（1）Subject：当前用户。

（2）Shiro SecurityManager：Shiro 大管家。

（3）Realm：用于访问数据库。

2.Shiro SecurityManager

Shiro 的大管家管理着 Shiro 下的认证、授权、会话管理、缓存管理、以及 Realm 访问数据库，贯穿于始终的是加密。

3.用户、角色、权限

（1）概念：

• 用户：通俗来讲，指的就是要登录的用户名密码。
• 角色：权限的集合。
• 权限：是否有能力去做某件事。

（2）关系

• 权限作用于角色，角色是权限的一个集合
• 角色作用于用户，用户是什么角色。

（3）维系关系

• 用户——角色：用户角色中间表。
• 角色——权限：角色权限中间表。

（4）以上所有的这些都归 Shiro 大管家来管理。

四、一个简单的官方的例子

1.需要导入的 jar 包。

2.官方demo。

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.authc.*;
import org.apache.shiro.config.IniSecurityManagerFactory;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.session.Session;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.util.Factory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Simple Quickstart application showing how to use Shiro's API.
 *
 * @since 0.9 RC2
 */
public class Quickstart {

    private static final transient Logger log = LoggerFactory.getLogger(Quickstart.class);

    public static void main(String[] args) {

        // The easiest way to create a Shiro SecurityManager with configured
        // realms, users, roles and permissions is to use the simple INI config.
        // We'll do that by using a factory that can ingest a .ini file and
        // return a SecurityManager instance:

        // Use the shiro.ini file at the root of the classpath
        // (file: and url: prefixes load from files and urls respectively):
        Factory<SecurityManager> factory = new IniSecurityManagerFactory("classpath:shiro.ini");
        SecurityManager securityManager = factory.getInstance();

        // for this simple example quickstart, make the SecurityManager
        // accessible as a JVM singleton.  Most applications wouldn't do this
        // and instead rely on their container configuration or web.xml for
        // webapps.  That is outside the scope of this simple quickstart, so
        // we'll just do the bare minimum so you can continue to get a feel
        // for things.
        SecurityUtils.setSecurityManager(securityManager);

        // Now that a simple Shiro environment is set up, let's see what you can do:

        // get the currently executing user:
        Subject currentUser = SecurityUtils.getSubject();

        // Do some stuff with a Session (no need for a web or EJB container!!!)
        Session session = currentUser.getSession();
        session.setAttribute("someKey", "aValue");
        String value = (String) session.getAttribute("someKey");
        if (value.equals("aValue")) {
            log.info("-->Retrieved the correct value! [" + value + "]");
        }

        // let's login the current user so we can check against roles and permissions:
        if (!currentUser.isAuthenticated()) {
            UsernamePasswordToken token = new UsernamePasswordToken("lonestarr", "vespa");
            token.setRememberMe(true);
            try {
                currentUser.login(token);
            } catch (UnknownAccountException uae) {
                log.info("-->There is no user with username of " + token.getPrincipal());
            } catch (IncorrectCredentialsException ice) {
                log.info("-->Password for account " + token.getPrincipal() + " was incorrect!");
            } catch (LockedAccountException lae) {
                log.info("The account for username " + token.getPrincipal() + " is locked.  " +
                        "Please contact your administrator to unlock it.");
            }
            // ... catch more exceptions here (maybe custom ones specific to your application?
            catch (AuthenticationException ae) {
                //unexpected condition?  error?
            }
        }

        //say who they are:
        //print their identifying principal (in this case, a username):
        log.info("-->User [" + currentUser.getPrincipal() + "] logged in successfully.");

        //test a role:
        if (currentUser.hasRole("schwartz")) {
            log.info("-->May the Schwartz be with you!");
        } else {
            log.info("Hello, mere mortal.");
        }

        //test a typed permission (not instance-level)
        if (currentUser.isPermitted("lightsaber:weild")) {
            log.info("-->You may use a lightsaber ring.  Use it wisely.");
        } else {
            log.info("Sorry, lightsaber rings are for schwartz masters only.");
        }

        //a (very powerful) Instance Level permission:
        if (currentUser.isPermitted("winnebago:drive:eagle5")) {
            log.info("-->You are permitted to 'drive' the winnebago with license plate (id) 'eagle5'.  " +
                    "Here are the keys - have fun!");
        } else {
            log.info("Sorry, you aren't allowed to drive the 'eagle5' winnebago!");
        }

        //all done - log out!
        currentUser.logout();

        System.exit(0);
    }
}

说明：获取 SecurityManager ，认证，认证失败的几种情况，成功登陆后是否拥有某个角色，某个角色是否有某个权限。

[users]
root = secret, admin
guest = guest, guest
presidentskroob = 12345, president
darkhelmet = ludicrousspeed, darklord, schwartz
lonestarr = vespa, goodguy, schwartz

[roles]
admin = *
schwartz = lightsaber:*
goodguy = winnebago:drive:eagle5

说明：Shiro.ini 文件，用来维系用户——角色——权限之间的关系。

3.ini 文件说明

[users]：用户名=密码，角色1，角色2

[roles]：角色=权限1，权限2

权限：

（1）用简单的字符串来表示一个权限。如：user

（2）多层次管理：如：user:query,user:edit,user:query,edit。第一部分为操作的领域，第二部分为执行的操作。可以使用通配符：user:*,*:query

（3）实例级权限：域：操作：实例

如：user:edit:manager 只能对 user 中的 manager 进行 edit。

通配符：user:edit:*、user:*:*、user:*:manager

等价：user:edit==user:edit:*、user == user:*:* 只能从字符串结尾处省略。

（4）可对比官方例子学习。

五、总结：

介绍了权限的基础，介绍了 Shiro 的 HelloWorld，要明白其中重要的部分，如：认证、授权，以及Shiro 是如何来做这两件事情的。介绍官方demo 的 ini 配置方式，只是想更加深刻的去理解

Shiro 的管理器，认证，授权，角色，权限等等这些概念。