Apache Portable Runtime

火冰狐

　　在调试一个项目时，注意到 Tomcat 打印了这样一个信息：
The Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path:
　　就开始google，发现缺少Apache Portable Runtime 的library。
　　Apache Portable Runtime：
　　http://tomcat.apache.org/tomcat-5.5-doc/apr.html
　　Tomcat can use the Apache Portable Runtimeto provide superior scalability, performance, and better integration with native server technologies. The Apache Portable Runtime is a highly portable library that is at the heart of Apache HTTP Server 2.x. APR has many uses, including access to advanced IOfunctionality (such as sendfile, epoll and OpenSSL), OS level functionality (random numbergeneration, system status, etc), and native process handling (shared memory, NTpipes and Unix sockets).
These features allows making Tomcat a general purpose webserver, will enable much better integration with other native web technologies, and overall make Java much more viable asa full fledged webserver platform rather than simply a backend focused technology.
　　大概意思是，Tomcat 通过APR 可以提高可扩展性和性能，APR是Apache HTTP Server 2.x 的可移植库，APR有很多用处，包括访问高级IO功能（例如发送文件、epoll、OpenSSL）、操作系统级功能（生成随机数、系统状态）和本地进程处理（共享内存、NTpipes and Unix sockets）。
　　这些特性使得Tomcat 成为一个通用的Web服务器，具备和其他本地web技术更好的可集成性，这些特性也让Java成为更为通用、成熟的web服务端平台，而不仅仅是一个简短后端技术。
　　在Window平台下，下载window的 ddl文件，复制到window/system32目录下，或安装到Tomcat，就不会在出现之前的提示了，而打印出这样的信息：
　　org.apache.coyote.http11.Http11AprProtocol init
　　org.apache.coyote.ajp.AjpAprProtocol init
　　Linux平台下的安装方法，请查看官方文档。