CentOS yum源

1.如何设置CentOS 5的yum源为上海交通大学网站

修改/etc/yum.repos.d/CentOS-Base.repo为:
CentOS-Base.repo
[base]
name=CentOS-5 - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever5&arch=$basearch&
repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
baseurl=http://ftp.sjtu.edu.cn/centos/5.0/os/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

#released updates
[update]
name=CentOS-5 - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=updates
baseurl=http://ftp.sjtu.edu.cn/centos/5.0/updates/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

#packages used/produced in the build but not released
[addons]
name=CentOS-5 - Addons
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=addons

baseurl=http://ftp.sjtu.edu.cn/centos/5.0/addons/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

#additional packages that may be useful
[extras]
name=CentOS-5 - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=extras

baseurl=http://ftp.sjtu.edu.cn/centos/5.0/extras/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-5 - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=centosplus
baseurl=http://ftp.sjtu.edu.cn/centos/5.0/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

#contrib - packages by Centos Users
[contrib]
name=CentOS-5 - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=contrib
baseurl=http://ftp.sjtu.edu.cn/centos/5.0/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5

2.中科大yum源
http://mirrors.ustc.edu.cn/centos/5/os/i386/