Debian Java环境

jdk8下载

wget https://download.oracle.com/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
直接解压在/root下， tar xzvf jdk-8u281-linux-x64.tar.gz
不行就去 官网 下载一个jdk8

安装maven

apt-get install maven
建议先安装maven，因为maven安装过程中依赖java环境，安装完会改java 命令路径

配置环境

#java
update-alternatives --install /usr/bin/java java  /root/jdk1.8.0_281/bin/java 2
update-alternatives --config java
#jar
update-alternatives --install /usr/bin/jar jar /root/jdk1.8.0_281/bin/jar 2
update-alternatives --set jar /root/jdk1.8.0_281/bin/jar
#javac
update-alternatives --install /usr/bin/javac javac /root/jdk1.8.0_281/bin/javac 2
update-alternatives --set javac /root/jdk1.8.0_281/bin/javac

配置 /etc/profile.d/jdk.sh

export J2SDKDIR=/root/jdk1.8.0_281
export J2REDIR=/root/jdk1.8.0_281
export PATH=$PATH:/root/jdk1.8.0_281/bin:/root/jdk1.8.0_281/db/bin
export JAVA_HOME=/root/jdk1.8.0_281
export DERBY_HOME=/root/jdk1.8.0_281/db

source /etc/profile.d/jdk.sh 引入环境变量

参考
https://tecadmin.net/install-oracle-java-on-debian-10-buster/