linux安装多个版本的java如何配置

jenkins 高版本已经不支持java8了，低版本插件安装问题很多。

jenkins 需要java17，研发程序需要使用java8

https://mirrors.tuna.tsinghua.edu.cn/jenkins/war-stable/2.401.1/jenkins.war

https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.tar.gz

https://download.oracle.com/otn/java/jdk/8u211-b12/478a62b7d4e34b78b671c754eaaf38ab/jdk-8u211-linux-x64.tar.gz

[root@vm ~]# tar xf jdk-17_linux-x64_bin.tar.gz
[root@vm ~]# tar xf jdk-8u211-linux-x64.tar.gz
[root@vm ~]# mv jdk1.8.0_211/ /opt/java8
[root@vm ~]# mv jdk-17.0.10 /opt/jdk17
[root@vm ~]# tail /etc/profile   # 先配置一个版本
...
export JAVA_HOME=/opt/jdk17
export PATH=$PATH:$JAVA_HOME/bin
[root@vm ~]# source /etc/profile
[root@vm ~]# java -version
java version "17.0.10" 2024-01-16 LTS# 版本配置
[root@vm ~]# update-alternatives --install /usr/bin/java java  /opt/java17/bin/java 1
[root@vm ~]# update-alternatives --install /usr/bin/java java  /opt/java8/bin/java 2# 选择版本1  java17
[root@vm ~]# update-alternatives --config javaThere are 2 programs which provide 'java'.Selection    Command
-----------------------------------------------1           /opt/java17/bin/java
*+ 2           /opt/java8/bin/javaEnter to keep the current selection[+], or type selection number: 1
[root@vm ~]# java -version
java version "17.0.10" 2024-01-16 LTS# 选择版本2  java8
[root@vm ~]# update-alternatives --config javaThere are 2 programs which provide 'java'.Selection    Command
-----------------------------------------------+ 1           /opt/java17/bin/java
*  2           /opt/java8/bin/javaEnter to keep the current selection[+], or type selection number: 2
[root@vm ~]# java -version
java version "1.8.0_211"# 启动jenkins[root@vm ~]# update-alternatives --config java
Enter to keep the current selection[+], or type selection number: 1[root@vm ~]# yum install fontconfig  #不装会有个小报错
[root@vm ~]# cd /app/
[root@vm app]# nohup java -Dhudson.model.DownloadService.noSignatureChecke=true -DJENKINS_HOME=/app/ -jar /app/jenkins.war &