Jenkins automated deployment has been used for a long time, but has never been deployed by itself
I have configured it in the past two days, just make a record
wget -q -O - https://pkg.jenkins.io/debian/jenkins-ci.org.key | sudo apt-key add - sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list' sudo apt-get update sudo apt-get install jenkins
Download and install jenkins first
start jenkins
sudo systemctl start jenkins
Jenkins default port is 8080
Then you can enter. Start by logging in and registering, then install some plugins, and that’s it.
Now we need to install a few more important plugins
maven git jdk
We already have git and jdk installed by default before.
So just install maven and it's ok
Then start configuring system settings
Install git, maven, jdk The installation path here is the installation path of your server
In the case of git, it is said on the Internet that the path should go to the execution directory, but in fact this is already the execution directory.
Then you can start configuring the project
When you enter the git path at the beginning of this block, an error will be reported because ssh is not configured
Clicking on the add 
block requires you to copy the private key of the ssh configured by the server, which is the one in the rsa file, and then just name it.
Then the error is resolved
Then step by step 
this is also bothering me for a long time root pom This must be the path of your project pom
Then because I deployed jetty, I added the above. If it is deployed by tomcat, it needs to be reset.
Click on the project to build now and it's successful
Main reference articles
http://www.linuxidc.com/Linux/2016-12/138290.htm
http://www.linuxdiyf.com/linux/21547.html