Introduction to Tomcat
Tomcat is a core project in the Jakarta project of the Apache Software Foundation, developed jointly by Apache, Sun and some other companies and individuals.
The website written by the java program uses tomcat+jdk to run
Tomcat is a middleware that really works, and it is jdk that parses the java script
JDK (java development kit) is the core of the entire java. It contains the java runtime environment, a bunch of java-related tools and java basic libraries.
The most mainstream jdk is the jdk released by sun company. In addition, IBM has also released JDK. You can also use yum to install openjdk on CentOS.
install jdk
jdk version 1.6, 1.7, 1.8
Official website download address http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Download jdk8 and put it in the /usr/local/src/ directory
cd /usr/local/src/
tar zxvf jdk-8u151-linux-x64.tar.gz
mv jdk1.8.0_151 /usr/local/jdk1.8
vi /etc/profile //Add at the end
JAVA_HOME=/usr/local/jdk1.8/
JAVA_BIN=/usr/local/jdk1.8/bin
JRE_HOME=/usr/local/jdk1.8/jre
PATH=$PATH:/usr/local/jdk1.8/bin:/usr/local/jdk1.8/jre/bin
CLASSPATH=/usr/local/jdk1.8/jre/lib:/usr/local/jdk1.8/lib:/usr/local/jdk1.8/jre/lib/charsets.ja
[root @localhost src]# source /etc/profile // After saving the file, make it effective
[root @localhost src]# java -version // Check whether the settings are correct
java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)
install tomcat
cd /usr/local/src
wget https://mirrors.tuna.tsinghua.edu.cn/apache/tomcat/tomcat-8/v8.5.24/bin/apache-tomcat-8.5.24.tar.gz
tar zxvf apache-tomcat-8.5.24.tar.gz
mv apache-tomcat-8.5.24 /usr/local/tomcat
/usr/local/tomcat/bin/startup.sh
（/usr/local/tomcat/bin/shutdown.sh）
ps aux|grep tomcat
netstat -lntp | grep java
The three ports 8080 are the ports for providing web services, 8005 is the management port, and port 8009 is the port for third-party service calls. For example, it will be used when httpd and Tomcat are combined.
iptables -nvL
[root@localhost src]# systemctl stop firewalld
[root@localhost src]# systemctl disable firewalld
Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.