The APR based Apache Tomcat Native library which allows optimal performance

    在启动tomcat时，发现有这样一条错误信息

    The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path:...

    出现这种情况是没有加载到APR的包，如果是tomcate 6，需要到 tomcat下载http://tomcat.heanet.ie/native/1.1.12/binaries/win32/tcnative-1.dll 这个dll并放到tomcat/bin下面。

   如果是tomcat 7 ,在bin下面已经有了这个文件，出现这种情况一般是在eclipse里面启动tomcat，这时候把tomcat/bin下面的这个dll拷贝到jdk/bin下面就可以了.

    再启动会发现启动信息变成了

     信息: Loaded APR based Apache Tomcat Native library 1.1.27 using APR version 1.4.6.
     2013-12-25 15:42:32 org.apache.catalina.core.AprLifecycleListener init
     信息: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].