tomcat启用native提高并发能力

tomcat默认使用BIO，未启用tomcat native。

tomcat native通过jni使用操作系统的高性能IO库，提高并发能力。
参考资料：     

        1. 安装依赖的软件包
            yum install apr apr-devel
            yum install apr-util apr-util-devel
            yum install java-1.7.0-openjdk-devel

        2. 编译，安装
            tar xzf /opt/apache-tomcat-7.0.56/bin/tomcat-native.tar.gz
            ./configure --with-apr=/usr --with-java-home=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.9.x86_64 --prefix=/opt/apache-tomcat-7.0.56
            make
            make install

        3. 配置tomcat
            编写/opt/apache-tomcat-7.0.56/bin/startup_native.sh
            加入库路径
                LD_LIBRARY_PATH=/opt/apache-tomcat-7.0.56/lib
                export LD_LIBRARY_PATH

            修改server.xml，禁用SSL
            /opt/apache-tomcat-7.0.56/conf/server.xml
               

        4. 检查是否正确安装
            查看tomcat启动日志catalina.out

            正确安装时出现如下日志
                Feb 05, 2015 9:12:05 AM org.apache.catalina.core.AprLifecycleListener init
                INFO: Loaded APR based Apache Tomcat Native library 1.1.31 using APR version 1.3.9.
                Feb 05, 2015 9:12:05 AM org.apache.catalina.core.AprLifecycleListener init
                INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].

            未正确安装时出现如下日志
                Feb 05, 2015 9:01:29 AM org.apache.catalina.core.AprLifecycleListener init
                INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib