Apache Shiro是一个强大易用的Java安全框架，提供了认证、授权、加密和会话管理功能，可为任何应用提供安全保障。本文主要介绍一下Shiro中的身份认证功能，如下： 
本文参考自Apache Shiro的官方文档：http://shiro.apache.org/authentication.html。
本文遵循以下流程：先介绍Shiro中的身份认证，再通过一个实例来具体说明一下（基于maven）。
1. 认证主体（Authenticating Subjects）
Subject 认证主体包含两个信息：
Principals：身份。可以是用户名，邮件，手机号码等等，用来标识一个登录主体身份；
Credentials：凭证。常见有密码，数字证书等等。
在Shiro中可以在.ini文件中指定一个认证主体，也可以从数据库中取，这里使用.ini文件来写一个简单的认证主体：
<code class="language-ini hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-title" style="box-sizing: border-box;">[users]</span>
<span class="hljs-setting" style="box-sizing: border-box;">csdn1=<span class="hljs-value" style="box-sizing: border-box;"><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">12345</span></span></span>
<span class="hljs-setting" style="box-sizing: border-box;">csdn2=<span class="hljs-value" style="box-sizing: border-box;"><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">12345</span></span></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>
可以表示两个用户，账号为csdn1和csdn2，密码都是12345。至于这个文件怎么用，后面我会在实例中介绍。
验证一个主体的方法可以有效地细分为三个不同的步骤：
Step 1：收集主体提交的身份和凭证；
Step 2：提交该身份和凭证；
Step 3：如果提交成功，允许访问，否则重新尝试身份验证或阻止访问。
Step 4：退出
下面说明Shiro中的API是如何反映以上步骤的：
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Step1: Collect the Subject's principals and credentials</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//根据用户名和密码获得一个令牌（token）</span>
UsernamePasswordToken token = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UsernamePasswordToken(username, password);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//token.setRememberMe(true); //可选用</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>
在Step1中，我们使用UsernamePasswordToken，支持最常用的用户名/密码认证方式。这是Shiro的org.apache.shiro.authc.AuthenticationToken接口，这是由Shiro的认证系统代表提交的主体和凭证使用的基本接口的实现。username和password就是和Subject认证主体中对应的身份和凭证做验证的。当然也可以记住该用户，这个可有可无，关于RememberMe将在后续文章中介绍。
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Step2: Submit the principals and credentials</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//得到当前执行的用户</span>
Subject currentUser = SecurityUtils.getSubject();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//进行认证</span>
currentUser.login(token);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>
在Step2中，先通过SecurityUtils工具类获取当前执行的用户，然后进行身份认证，这个认证会参考ini文件中的Subject主体（当然了，实际中是参考数据库中的信息），在下面的示例程序中可以看的出。
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Step3: Handling Success or Failure</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
currentUser.login(token);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> ( AuthenticationException ae ) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//unexpected error?</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Handel error</span>
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//No problems, continue on as expected...</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>
在Step3中，我们要根据认证的结果来处理正确或者错误的结果，所以我们需要将currentUser.login(token)使用try/catch包起来。
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Step4: Logging out</span>
currentUser.logout();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
与认证相反的是释放所有已知的确定的状态。当主体完成与应用程序交互，可以调用subject.logout（）放弃所有的身份信息，subject.logout（）会删除所有身份信息以及他们的会话（这里的会话指的是Shiro中的会话）。
2. 认证过程（Authentication Sequence）
上文介绍了认证主体，以及从代码的角度来分析了一下身份认证过程。下面来看一下在身份认证中，Shiro里面都干了些啥。图出自官方文档： 
Step1：应用程序代码在调用Subject.login(token)方法后，传入代表最终用户的身份和凭证构造的AuthenticationToken实例token。
Step2：将Subject实例委托给应用程序的SecurityManager（Shiro的安全管理）通过调用securityManager.login（token）来开始实际的认证工作。这里开始真正的认证工作了。
Step3，4，5：然后SecurityManager就会根据具体的reaml去进行安全认证了。
这个realm到底是啥呢？realm就是一个域，Shiro就是从realm中获取验证数据的，也就是我们写在.ini文件中的东西，当然了，这个realm有很多种，如text realm、jdbc realm、jndi realm等，text realm比较简单，这一节主要总结一下jdbc realm的使用，text realm也会提到。
3. 身份认证示例
示例的工程结构如下： 
pom.xml中的包如下：
<code class="language-xml hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">project</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://maven.apache.org/POM/4.0.0"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:xsi</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://www.w3.org/2001/XMLSchema-instance"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xsi:schemaLocation</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">modelVersion</span>></span>4.0.0<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">modelVersion</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>demo.shiro<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>Shiro02<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>0.0.1-SNAPSHOT<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">name</span>></span>Shiro02<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">name</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">description</span>></span>Shiro02<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">description</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">build</span>/></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependencies</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>org.apache.shiro<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>shiro-core<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>1.2.5<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>org.slf4j<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>slf4j-log4j12<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>1.7.21<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>c3p0<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>c3p0<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>0.9.1.2<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>commons-logging<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>commons-logging<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>1.2<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>mysql<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">groupId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>mysql-connector-java<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">artifactId</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>5.1.38<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">version</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependency</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">dependencies</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">project</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li></ul>
log4j.properties文件如下：
<code class="language-properties hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootLogger</span>=INFO, stdout
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span>=org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.log</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ConsoleAppender</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span>=org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.log</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.PatternLayout</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.appender</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.stdout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layout</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ConversionPattern</span>=%d %p [%c] - %m %n
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># General Apache libraries</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span>=WARN
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Spring</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span>=WARN
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Default Shiro logging</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shiro</span>=TRACE
<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;"># Disable verbose logging</span>
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shiro</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.util</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ThreadContext</span>=WARN
log4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.logger</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.org</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.shiro</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.cache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ehcache</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.EhCache</span>=WARN</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>
首先写一个shiro.ini文件，文件内容很简单，只放一个用户信息：
<code class="language-ini hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-title" style="box-sizing: border-box;">[users]</span>
<span class="hljs-setting" style="box-sizing: border-box;">csdn=<span class="hljs-value" style="box-sizing: border-box;"><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">123</span></span></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
然后开始写身份认证的java代码了，如下：
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">TextRealm</span> {</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 读取配置文件，初始化SecurityManager工厂</span>
Factory<SecurityManager> factory = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> IniSecurityManagerFactory(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"classpath:shiro.ini"</span>);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 获取securityManager实例</span>
SecurityManager securityManager = factory.getInstance();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 把securityManager实例绑定到SecurityUtils</span>
SecurityUtils.setSecurityManager(securityManager);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 创建token令牌，用户名/密码</span>
UsernamePasswordToken token = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UsernamePasswordToken(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"csdn"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"123"</span>);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 得到当前执行的用户</span>
Subject currentUser = SecurityUtils.getSubject();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 身份认证</span>
currentUser.login(token);
System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"身份认证成功！"</span>);
}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(AuthenticationException e){
e.printStackTrace();
System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"身份认证失败！"</span>);
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 退出</span>
currentUser.logout();
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li></ul>
运行该程序就可以根据传入的参数和realm中的数据进行匹对，完成身份认证，从而打印认证成功，如果用户名和密码填写一个错误的，则会验证失败。
接下来再分析一下jdbc realm的写法，首先新建一个JdbcRealm.ini文件，如下：
<code class="language-ini hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-title" style="box-sizing: border-box;">[main]</span>
#数据源选择的是c3p0
<span class="hljs-setting" style="box-sizing: border-box;">dataSource=<span class="hljs-value" style="box-sizing: border-box;">com.mchange.v2.c3p0.ComboPooledDataSource</span></span>
dataSource.driverClass=com.mysql.jdbc.Driver
dataSource.jdbcUrl=jdbc:mysql://localhost:3306/db_shiro
dataSource.user=root
dataSource.password=root
#定义一个jdbc的realm，取名为jdbcRealm
<span class="hljs-setting" style="box-sizing: border-box;">jdbcRealm=<span class="hljs-value" style="box-sizing: border-box;">org.apache.shiro.realm.jdbc.JdbcRealm</span></span>
#jdbcRealm中有个属性是dataSource，选择我们上边定义的dataSource
jdbcRealm.dataSource=$dataSource
#SecurityManager中的realm选择上面定义的jdbcRealm
securityManager.realms=$jdbcRealm
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul>
然后需要准备数据库的数据，我新建了一个数据库db_shiro，里面有个users表，两个字段username和password，我就放了三个数据用来测试的，如下： 
然后写JdbcRealm.java代码，和上面的一样的，只不过读取的配置文件不同
<code class="language-java hljs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">JdbcRealm</span> {</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 读取配置文件，初始化SecurityManager工厂</span>
Factory<SecurityManager> factory = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> IniSecurityManagerFactory(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"classpath:jdbc_realm.ini"</span>);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 获取securityManager实例</span>
SecurityManager securityManager = factory.getInstance();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 把securityManager实例绑定到SecurityUtils</span>
SecurityUtils.setSecurityManager(securityManager);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 得到当前执行的用户</span>
Subject currentUser = SecurityUtils.getSubject();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 创建token令牌，用户名/密码</span>
UsernamePasswordToken token = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> UsernamePasswordToken(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"倪升武2"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"123"</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 身份认证</span>
currentUser.login(token);
System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"身份认证成功！"</span>);
}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(AuthenticationException e){
e.printStackTrace();
System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"身份认证失败！"</span>);
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 退出</span>
currentUser.logout();
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li></ul>
这样Shiro就会根据这个jdbc realm从数据库中获取验证数据对传入的参数进行身份验证，验证通过则打印出通过的语句，否则不予通过。这就是Shiro中简单的身份认证，下一节将总结一下Shiro中的权限认证，即授权。
—–乐于分享，共同进步！
—–我的博客主页：http://blog.csdn.net/eson_15