无法在Ubuntu 18.04.2 LTS上安装tomcat7
ubuntu@ip-10-0-xx-xxx:~$ sudo apt-get -q -y -o DPkg::Options::=--force-confold install tomcat7
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package tomcat7
ubuntu@ip-10-0-xx-xxx:~$
如何显式添加存储库？