#先准备一个脚本
[root@hadoop /]#vi /root/test.sh
#里面加上内容
echo "" > ~/.bashrc
cat <<EOF > ~/.bashrc
# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
  . /etc/bashrc
fi

# Uncomment the following line if you don't like systemctl's auto-paging feature:
# export SYSTEMD_PAGER=

# User specific aliases and functions

export JAVA_HOME=/usr/lib/jdk-11
export PATH=$JAVA_HOME/bin:$PATH
EOF

#root用户下执行命令
[root@hadoop /]#java -version
openjdk version "1.8.0_282"
OpenJDK Runtime Environment (build 1.8.0_282-b08)
OpenJDK 64-Bit Server VM (build 25.282-b08, mixed mode)

#查询到当前hadoop用户的java环境变量为1.8
[root@hadoop /]#su - hadoop -c "java -version"
openjdk version "1.8.0_282"
OpenJDK Runtime Environment (build 1.8.0_282-b08)
OpenJDK 64-Bit Server VM (build 25.282-b08, mixed mode)

#执行改变环境变量的脚本
[root@hadoop /]#su - hadoop -c "bash /root/test.sh"

#再次查询到jdk变11了
[root@hadoop /]#su - hadoop -c "java -version"
ls: cannot access /usr/lib/spark-current/yarn/spark-*-yarn-shuffle.jar: No such file or directory
java version "11.0.10" 2021-01-19 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.10+8-LTS-162)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.10+8-LTS-162, mixed mode)