JDK8 installation and jenkins installation

1. Download
jdk-8u144-linux-x64.tar.gz and extract it to the jvm directory
2. Extract it to the server directory
cd /usr/lib/jvm/
tar -zxvf jdk-8u144-linux-x64.tar.gz
3. Edit the configuration File
vi /etc/profile

export JAVA_HOME=/usr/lib/jvm/jdk1.8.0_144
export CLASSPATH=.:$JAVA_HOME/lib
export PATH=$JAVA_HOME/bin:$PATH

source /etc/profile

4. Change the default JDK version
Since there may be other default versions of JDK in the system, in order to set the JDK we installed as the default JDK version, the following work is required. (note the path specified)
update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.8.0_144/bin/java 300 
update-alternatives --install /usr/bin/javac javac /usr /lib/jvm/jdk1.8.0_144/bin/javac 300 
update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.8.0_144/bin/jar 300  
update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/jdk1.8.0_144/bin/javah 300  
update-alternatives --install /usr/bin/javap javap /usr/lib/jvm/jdk1 .8.0_144/bin/javap 300 
Execute the following command to set the default version. After this command is executed, the system will list the various JDK versions currently existing, and you will be prompted to select
5. Jenkins (unified build) Update installation
(1), Download
wget http://updates.jenkins-ci.org/download/war/2.32.2/jenkins.war
(2), install tomcat, configure port 9080 and set URIEncoding="UTF-8"
(3), configure catalina. sh
JENKINS_HOME="/mnt/jenkins"
or set JENKINS_HOME="/mnt/jenkins" in
/etc/profile
(4), update all recommended plugins