miaosha/docs/tomcat-good.md

xiu修改### 秒杀tomcat优化

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##要求：

本文以tomcat8.5.20为准 目标

1.内存优化
2.并发优化
3.APR优化

APR优化相关包

1.内存优化

内存优化catalina
JAVA_OPTS="-server -Xms2048M -Xmx2048M -XX:+HeapDumpOnOutOfMemoryError 
-XX:HeapDumpPath=$CATALINA_HOME/logs/heap.dump"
# Register custom URL handlers
server.xml 配置
maxConnections="300"
acceptCount="200"
maxThreads="400"
minSpareThreads="200"/>
禁用
<!-- Define an AJP 1.3 Connector on port 8009 
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />-->

${tomcat}/webapps/docs/config/host.html
    
autoDeploy：This flag value indicates if Tomcat should check periodically for new or updated web applications while Tomcat is running
    
${tomcat}/webapps/docs/config/http.html
enableLookups：false
    
${tomcat}/webapps/docs/config/context.html:
reloadable：false

2.如果你的网站具有高并发那么建议使用APR模式

   http://apr.apache.org/
   依赖：

APR 1.2+ development headers (libapr1-dev package) OpenSSL 1.0.2+ development headers (libssl-dev package) JNI headers from Java compatible JDK 1.4+ GNU development environment (gcc, make)

   yum install apr* openssl-devel gcc make
   
   tar zxvf apr-1.4.5.tar  
   cd apr-1.4.5  
   ./configure --prefix=/usr/local/apr  
   make  
   make install  
   
   tar -zxvf apr-iconv-1.2.1.tar.gz  
   cd apr-iconv-1.2.1  
   ./configure --prefix=/usr/local/apr-iconv --with-apr=/usr/local/apr  
   make  
   make install
   
   yum install expat-devel
   
   tar zxvf apr-util-1.3.12.tar.gz  
   cd apr-util-1.3.12  
   ./configure --prefix=/usr/local/apr-util --with-apr=/usr/local/apr
   make  
   make install 
   
   安装openssl 1.0.2
   ./config  --prefix=/usr/local/openssl
   修改Makefile：
   vi Makefile
   将原来的：CFLAG=     -DOPENSSL_THREADS
   修改为：  CFLAG= -fPIC -DOPENSSL_THREADS
   也就是添加-fPIC
   执行执行：
   make && make install
   
   cd bin
   tar -zxvf tomcat-native.tar.gz
   cd tomcat-native-1.2.12-src
   cd native
   ./configure --with-apr=/usr/local/apr --with-ssl=/usr/local/openssl 
   make
   make install
   
   catalina.sh：
   JAVA_OPTS="$JAVA_OPTS -Djava.library.path=/usr/local/apr/lib
   注意：开启了apr之后，jvm用到的native内存会增大，因此要适当调大Metaspace空间,添加JVM选项：-XX:MetaspaceSize=128m
   JAVA_OPTS="-server -Xms2048M -Xmx2048M -XX:MetaspaceSize=128M -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=$CATALINA_HOME/logs/heap.dump"
   
   server.xml：
   <Connector port="8080" protocol="org.apache.coyote.http11.Http11AprProtocol"
   connectionTimeout="20000"
   redirectPort="8443" />
   
   <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="off" />