原文网址：http://blog.chinaunix.net/uid-15041-id-4821715.html
一、编辑更新源文件：/etc/apt/sources.list
二、更新源索引文件：apt-get update
三、国内的更新源：
搜狐源：
deb http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
网易163源：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
oschina源：
deb http://mirrors.oschina.net/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.oschina.net/ubuntu/ trusty-backports main restricted universe multiverse
deb http://mirrors.oschina.net/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.oschina.net/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.oschina.net/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.oschina.net/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.oschina.net/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.oschina.net/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.oschina.net/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.oschina.net/ubuntu/ trusty-updates main restricted universe multiverse
原文网址：http://blog.chinaunix.net/uid-29970837-id-4571602.html
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这是在下现在正使用的ubuntu14.04 trusty的源，对！你没有看错就是14.04虽然还未发布还在开发当中，但为了体现一下奉献精神在下就当了一回小白鼠14.04计划一推出我就立上立马上马的换成14.04 trusty的源了。 各位用ubuntu的linuxer不妨也踊跃的换成14.04的源慢慢滚动着升级到14.04正式版，因为经在下亲测我的ubuntu完全没问题（我是从13.10的测试版升的，别的版本不敢保证）。好了下面就把我用的几个源奉上吧：
#------------------ubuntu14.04 trusty(sohu#山东网通用户强烈建议#)-----------------------#
deb http://mirrors.sohu.com/ubuntu/ trusty multiverse universe restricted main
deb http://mirrors.sohu.com/ubuntu/ trusty-updates multiverse universe restricted main
deb http://mirrors.sohu.com/ubuntu/ trusty-backports multiverse universe restricted main
deb http://mirrors.sohu.com/ubuntu/ trusty-security multiverse universe restricted main
deb http://mirrors.sohu.com/ubuntu/ trusty-proposed multiverse universe restricted main
#-------------ubuntu14.04 trusty(163#网易电信网通双线接入网速杆杆的#)-----------------#
deb http://mirrors.163.com/ubuntu/ trusty main multiverse restricted universe
deb http://mirrors.163.com/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirrors.163.com/ubuntu/ trusty-updates main multiverse restricted universe
deb http://mirrors.163.com/ubuntu/ trusty-proposed universe restricted multiverse main
deb http://mirrors.163.com/ubuntu/ trusty-backports main multiverse restricted universe
#-------------------ubuntu14.04 trusty(taiwan)--------------------------#
# deb http://tw.archive.ubuntu.com/ubuntu/ trusty multiverse universe restricted main
# deb http://tw.archive.ubuntu.com/ubuntu/ trusty-security multiverse universe restricted main
# deb http://tw.archive.ubuntu.com/ubuntu/ trusty-updates multiverse universe restricted main
# deb http://tw.archive.ubuntu.com/ubuntu/ trusty-proposed multiverse universe restricted main
# deb http://tw.archive.ubuntu.com/ubuntu/ trusty-backports multiverse universe restricted main
#-------------------ubuntu14.04 trusty(上海交通大学)--------------------------#
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty universe restricted multiverse main
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-security universe restricted multiverse main
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-updates universe restricted multiverse main
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-proposed universe restricted multiverse main
deb http://ftp.sjtu.edu.cn/ubuntu/ trusty-backports universe restricted multiverse main
#-------------------ubuntu14.04 trusty(北京交通大学)--------------------------#
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty universe restricted multiverse main
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-security universe restricted multiverse main
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-updates universe restricted multiverse main
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-proposed universe restricted multiverse main
deb http://mirror.bjtu.edu.cn/ubuntu/ trusty-backports universe restricted multiverse main
原文网址：http://www.cnblogs.com/krazysky/p/3683991.html
网友可自己访问： http://mirrors.163.com/.help/ubuntu.html 里面详细说明， 支持最新的 Ubuntu 14.04。
以trusty(14.04)为例, 编辑/etc/apt/sources.list文件, 在文件最前面添加以下条目(操作前请做好相应备份)：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
然后执行 sudo apt-get update 获取新的软件列表。下载一个 open jdk，比原来的快很多， 几分钟就下完了。