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The Apache Software Foundation is a non-profit organization that manages various open-source software projects, including the Apache HTTP Server, Tomcat, and Hadoop. Their mission is to provide software for the public good and to support communities of developers, users, and contributors. The Apache HTTP Server is the most popular web server software in the world, used by millions of websites. The Apache Software Foundation also provides support and resources for developers working on other open-source projects, and they encourage collaboration and innovation in the software development community.

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http://www.apache.org/dyn/closer.cgi/hadoop/core/

根据提供的链接，这是Apache Hadoop的下载页面。用户可以通过该页面选择合适的下载镜像来获取Hadoop软件包。

根据提供的引用内容，我无法提供具体的演示或介绍，因为该链接只是指向了Apache Hadoop的下载页面，并没有提供具体的问题或需求。如果您有关于Hadoop的具体问题或需求，请提供更多详细信息，我将尽力为您提供帮助。

SLF4J: No SLF4J providers were found. SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See https://www.slf4j.org/codes.html#noProviders for further details. Exception in thread "main" org.apache.shiro.config.ConfigurationException: Unable to instantiate class [org.apache.shiro.web.mgt.DefaultWebSecurityManager] for object named 'securityManager'. Please ensure you've specified the fully qualified class name correctly. at org.apache.shiro.config.ReflectionBuilder.createNewInstance(ReflectionBuilder.java:309) at org.apache.shiro.config.ReflectionBuilder$InstantiationStatement.doExecute(ReflectionBuilder.java:927) at org.apache.shiro.config.ReflectionBuilder$Statement.execute(ReflectionBuilder.java:887) at org.apache.shiro.config.ReflectionBuilder$BeanConfigurationProcessor.execute(ReflectionBuilder.java:765) at org.apache.shiro.config.ReflectionBuilder.buildObjects(ReflectionBuilder.java:260) at org.apache.shiro.config.IniSecurityManagerFactory.buildInstances(IniSecurityManagerFactory.java:167) at org.apache.shiro.config.IniSecurityManagerFactory.createSecurityManager(IniSecurityManagerFactory.java:130) at org.apache.shiro.config.IniSecurityManagerFactory.createSecurityManager(IniSecurityManagerFactory.java:108) at org.apache.shiro.config.IniSecurityManagerFactory.createInstance(IniSecurityManagerFactory.java:94) at org.apache.shiro.config.IniSecurityManagerFactory.createInstance(IniSecurityManagerFactory.java:46) at org.apache.shiro.config.IniFactorySupport.createInstance(IniFactorySupport.java:123) at org.apache.shiro.util.AbstractFactory.getInstance(AbstractFactory.java:47) at com.xiu.Quickstart.main(Quickstart.java:26) Caused by: org.apache.shiro.util.UnknownClassException: Unable to load class named [org.apache.shiro.web.mgt.DefaultWebSecurityManager] from the thread context, current, or system/application ClassLoaders. All heuristics have been exhausted. Class could not be found. at org.apache.shiro.util.ClassUtils.forName(ClassUtils.java:152) at org.apache.shiro.util.ClassUtils.newInstance(ClassUtils.java:168) at org.apache.shiro.config.ReflectionBuilder.createNewInstance(ReflectionBuilder.java:302) ... 12 more

这个异常是因为 Shiro 框架没有找到 SLF4J（Simple Logging Facade for Java）的实现类，导致默认使用了 NOP（No-Operation）日志记录器实现。

可以通过以下几个步骤解决这个异常：

1. 确保在应用程序的 classpath 下存在 SLF4J 的实现类，比如 Logback、Log4j 等。
2. 确认应用程序中已经正确引入了 SLF4J 的依赖，比如以下 Maven 依赖：

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.30</version>
</dependency>
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.3</version>
</dependency>

3. 确认 SLF4J 的配置文件是否正确，比如 logback.xml 或者 log4j.properties 等。

如果以上步骤都没有解决问题，可以尝试修改 Shiro 的日志记录器实现类，比如使用 Logback 作为日志记录器实现：

# 修改 Shiro 的日志记录器实现类为 Logback
log4j.logger.org.apache.shiro=INFO, stdout
log4j.logger.org.apache.shiro.util.ThreadContext=INFO, stdout
log4j.logger.org.apache.shiro.realm=INFO, stdout
log4j.logger.org.apache.shiro.web=INFO, stdout
log4j.logger.org.apache.shiro.cache=INFO, stdout
log4j.logger.org.apache.shiro.session=INFO, stdout

# Logback 配置文件，可以将日志输出到控制台
<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>
    <logger name="org.apache.shiro" level="INFO"/>
    <root level="DEBUG">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>