tomcat 简介

Tomcat是一款我们平时开发过程中最常用到的Servlet容器。本系列博客会记录Tomcat(以Tomcat 7为列)的整体架构、核心组件、IO线程模型、请求在Tomcat内部的流转过程以及一些Tomcat调优的相关知识点。力求能达到以下几个目的：

更加熟悉Tomcat的工作机制，工作中遇到Tomcat相关问题能够快速定位，从源头来解决；
对于一些高并发场景能够对Tomcat进行调优；
通过对Tomcat源码的分析，吸收一些Tomcat的设计的理念，应用到自己的软件开发过程中。

tomcat 是什么

tomcat就是传说中的中间件之一，tomcat本身是一个容器，专门用来运行java程序，java语言开发的网页.jsp就应该运行于tomcat中。而tomcat本身的运行也依赖于jdk环境。

tomcat官网

tomcat项目部署

准备工作
// 关闭防火墙和selinux
[root@localhost bin]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost bin]# setenforce 0

安装java环境
[root@localhost ~]# cd /usr/src
[root@localhost src]# ls
debug  kernels
[root@localhost src]# yum -y install java-11-openjdk*

// 下载tomcat
[root@localhost src]# wget https://archive.apache.org/dist/tomcat/tomcat-9/v9.0.53/bin/apache-tomcat-9.0.53.tar.gz

// 解压
[root@localhost src]# tar xf apache-tomcat-9.0.53.tar.gz -C /usr/local/
[root@localhost src]# cd /usr/local/
[root@localhost local]# ls
apache-tomcat-9.0.53  bin  etc  games  include  lib  lib64  libexec  sbin  share  src
// 更改名字
[root@localhost local]# mv apache-tomcat-9.0.53 tomcat

// 写一个java页面
[root@localhost local]# cd
[root@localhost ~]# cat > index.jsp <<EOF
> <html>
> <head>
>         <title>test page</title>
> </head>
> <body>
>         <%
>           out.println("Hello Java");
>         %>
> </body>
> </html>
> EOF
[root@localhost ~]# mkdir /usr/local/tomcat/webapps/amu
[root@localhost ~]# cp index.jsp /usr/local/tomcat/webapps/amu/

// 启动、停止tomcat脚本
[root@localhost ~]# cd /usr/local/tomcat/bin/
[root@localhost bin]# ls
bootstrap.jar                 makebase.sh
catalina-tasks.xml            setclasspath.bat
catalina.bat                  setclasspath.sh
catalina.sh                   shutdown.bat
ciphers.bat                   shutdown.sh
ciphers.sh                    startup.bat
commons-daemon-native.tar.gz  startup.sh
commons-daemon.jar            tomcat-juli.jar
configtest.bat                tomcat-native.tar.gz
configtest.sh                 tool-wrapper.bat
daemon.sh                     tool-wrapper.sh
digest.bat                    version.bat
digest.sh                     version.sh
makebase.bat

// 启动tomcat
[root@localhost bin]# /usr/local/tomcat/bin/startup.sh start
Using CATALINA_BASE:   /usr/local/tomcat
Using CATALINA_HOME:   /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.
[root@localhost bin]# ss -antl
State  Recv-Q Send-Q      Local Address:Port   Peer Address:Port                        Process                         
LISTEN 0      128               0.0.0.0:22          0.0.0.0:*                                                           
LISTEN 0      1      [::ffff:127.0.0.1]:8005              *:*         //必须有8085端口才可以用脚本停止服务                                                  
LISTEN 0      100                     *:8080              *:*                                                           
LISTEN 0      128                  [::]:22             [::]:*

查看web页面

web页面管理

// 修改配置文件
[root@localhost bin]# cd /usr/local/tomcat/conf/
[root@localhost conf]# ls
Catalina             jaspic-providers.xml  tomcat-users.xml
catalina.policy      jaspic-providers.xsd  tomcat-users.xsd
catalina.properties  logging.properties    web.xml
context.xml          server.xml
[root@localhost conf]# vim tomcat-users.xml 
// 末尾加三行
[root@localhost conf]# tail -5 tomcat-users.xml 
-->
<role rolename="admin-gui"/>    // 加这一行
<role rolename="manager-gui"/>  // 加这一行
<user username="tomcat" password="tomcat" roles="manager-gui, admin-gui"/>  // 加这一行
</tomcat-users>

[root@localhost conf]# cd /usr/local/tomcat/webapps/
[root@localhost webapps]# ls
ROOT  amu  docs  examples  host-manager  manager
[root@localhost webapps]# cd manager/
[root@localhost manager]# ls
META-INF  css     index.jsp   xform.xsl
WEB-INF   images  status.xsd
[root@localhost manager]# vim META-INF/context.xml 

<Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="192\.168\.91\.\d+|127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />  // 加入本机网段
  <Manager sessionAttributeValueClassNameFilter="java\.lang\
  
// 重启服务
[root@localhost manager]# /usr/local/tomcat/bin/shutdown.sh
Using CATALINA_BASE:   /usr/local/tomcat
Using CATALINA_HOME:   /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
NOTE: Picked up JDK_JAVA_OPTIONS:  --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED
[root@localhost manager]# ss -antl
State  Recv-Q Send-Q Local Address:Port   Peer Address:Port Process                                                     
LISTEN 0      128          0.0.0.0:22          0.0.0.0:*                                                                
LISTEN 0      128             [::]:22             [::]:*                                                                
[root@localhost manager]# /usr/local/tomcat/bin/startup.sh start
Using CATALINA_BASE:   /usr/local/tomcat
Using CATALINA_HOME:   /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.
[root@localhost manager]# ss -antl
State  Recv-Q Send-Q      Local Address:Port   Peer Address:Port                        Process                         
LISTEN 0      128               0.0.0.0:22          0.0.0.0:*                                                           
LISTEN 0      1      [::ffff:127.0.0.1]:8005              *:*                                                           
LISTEN 0      100                     *:8080              *:*                                                           
LISTEN 0      128                  [::]:22             [::]:*