这个问题是前几天发现的，在电脑上安装虚拟机，然后在上面装了大学时老师给的linux景象。配置好静态地址之后，使用yum安装jdk，发现报了下面的错误：
[root@localhost ~]# yum install java-1.8.0-openjdk* Loaded plugins: fastestmirror, security Loading mirror speeds from cached hostfile YumRepo Error: All mirror URLs are not using ftp, http[s] or file.Eg. Invalid release/ removing mirrorlist with no valid mirrors: /var/cache/yum/base/mirrorlist.txt Error: Cannot find a valid baseurl for repo: base 在网上查遍了各种办法都不奏效，后来把配置文件（/etc/yum.repos.d/CentOS-Base.repo）中的url拷贝到浏览器访问了一下，真的是url无效导致的。
于是直接访问了mirror.centos.org，点击到5.11之后，打开readme，显示如下：
This directory (and version of CentOS) is depreciated. CentOS-5 is now past EOL You can get the last released version of centos 5.11 here: http://vault.centos.org/5.11/ Please NOTE: this is not being maintained for security since moving to Vault. It will have security issues, you should upgrade to a new version instead. 于是把配置文件中所有mirrorlist注释掉，把baseurl都改成：
http://vault.centos.org/5.11/centosplus/$basearch/ 然后就可以了。
最后贴一份完整的配置文件，修改之前记得备份：
# CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # #[base] name=CentOS-5.11 - Base #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=os baseurl=http://vault.centos.org/5.11/os/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5#released updates [updates] name=CentOS-5.11 - Updates #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=updates baseurl=http://vault.centos.org/5.11/updates/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5#packages used/produced in the build but not released [addons] name=CentOS-5.11 - Addons #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=addons baseurl=http://vault.centos.org/5.11/addons/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5#additional packages that may be useful [extras] name=CentOS-5.11 - Extras #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=extras baseurl=http://vault.centos.org/5.11/extras/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5#additional packages that extend functionality of existing packages [centosplus] name=CentOS-5.11 - Plus #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=centosplus baseurl=http://vault.centos.org/5.11/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5#contrib - packages by Centos Users [contrib] name=CentOS-5.11 - Contrib #mirrorlist=http://mirrorlist.centos.org/?release=5.11&arch=$basearch&repo=contrib baseurl=http://vault.centos.org/5.11/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5喜欢本文的朋友不要忘记点一个免费的赞哦，你的赞将是我最大的动力。