tar命令打包Java安裝目錄（通常位于/usr/lib/jvm）：sudo tar -czvf java_install_backup.tar.gz /usr/lib/jvm
/etc/environment或用戶級配置文件（如~/.bashrc）：sudo cp /etc/environment /etc/environment_backup
cp ~/.bashrc ~/.bashrc_backup
java.security、java.properties等配置文件：sudo tar -czvf java_config_backup.tar.gz /usr/lib/jvm/*/lib/security/* /usr/lib/jvm/*/lib/*.properties
sudo tar -xzvf java_install_backup.tar.gz -C /
sudo cp /etc/environment_backup /etc/environment
source /etc/environment
sudo cp java_config_backup.tar.gz /usr/lib/jvm/ # 解壓后覆蓋對應文件
