如果你使用低于4.0版本eclipse，在线安装egit，会提示失败，因为线上的是支持eclipse4.0以上的egit。
所以请参照这个列表，自己选择url，进行安装。
比如我现在使用的是eclipse3.7版本。
所以我选择：
http://download.eclipse.org/egit/updates-1.3 进行在线更新 这样就没问题了。
EGIT和Eclipse对应关系：
| EGit | released for | Supported Version of Eclipse |
|---|---|---|
| 3.1.0.201310021548-r | N/A | Eclipse 3.8.2/4.2.2 + (Juno) |
| 3.0.3.201309161630-r | 4.3.1 (Kepler SR1) | Eclipse 3.8.2/4.2.2 + (Juno) |
| 3.0.1.201307141637-r | 4.3.0 (Kepler) | Eclipse 3.8.2/4.2.2 + (Juno) |
| 2.3.1.201302201838-r | 3.8.2/4.2.2 (Juno SR2) | Eclipse 3.7.2+ (Indigo) (except EGit Import Support feature, which is optional) |
| 2.2.0.201212191850-r | 3.8.1/4.2.1 (Juno SR1) | Eclipse 3.7.2+ (Indigo) (except EGit Import Support feature, which is optional) |
| 2.1.0.201209190230-r | 3.8.1/4.2.1 (Juno SR1) | Eclipse 3.5.2+ (Galileo) (except EGit Import Support feature, which is optional) |
| 2.0.0.201206130900-r | 3.8/4.2 (Juno) | Eclipse 3.5.2+ (Galileo) (except EGit Import Support feature, which is optional) |
| 1.3.0.201202151440-r | 3.7.2 (Indigo SR2) | Eclipse 3.5.2+ (Galileo) |
| 1.2.0.201112221803-r | 3.7.2 (Indigo SR2) | Eclipse 3.5.2+ (Galileo) |
| 1.1.0.201109151100-r | 3.7.1 (Indigo SR1) | Eclipse 3.5.2+ (Galileo) |
| 1.0.0.201106090707-r | 3.7.0 (Indigo) | Eclipse 3.5.2+ (Galileo) |
EGIT下载地址：
| Release Version | p2 repository URL | browse p2 repository |
|---|---|---|
| 3.1.0.201310021548-r (latest release) | http://download.eclipse.org/egit/updates-3.1 | updates-3.1 |
| 3.0.3.201309161630-r | http://download.eclipse.org/egit/updates-3.0.3 | updates-3.0.3 |
| 3.0.1.201307141637-r | http://download.eclipse.org/egit/updates-3.0.1 | updates-3.0.1 |
| 3.0.0.201306101825-r | http://download.eclipse.org/egit/updates-3.0 | updates-3.0 |
| 2.3.1.201302201838-r | http://download.eclipse.org/egit/updates-2.3 | updates-2.3 |
| 2.2.0.201212191850-r | http://download.eclipse.org/egit/updates-2.2 | updates-2.2 |
| 2.1.0.201209190230-r | http://download.eclipse.org/egit/updates-2.1 | updates-2.1 |
| 2.0.0.201206130900-r | http://download.eclipse.org/egit/updates-2.0 | updates-2.0 |
| 1.3.0.201202151440-r | http://download.eclipse.org/egit/updates-1.3 | updates-1.3 |
| 1.2.0.201112221803-r | http://download.eclipse.org/egit/updates-1.2 | updates-1.2 |
| 1.1.0.201109151100-r | http://download.eclipse.org/egit/updates-1.1 | updates-1.1 |
| 1.0.0.201106090707-r | http://download.eclipse.org/egit/updates-1.0 | updates-1.0 |
| 0.12.1 (Incubation) | http://download.eclipse.org/egit/updates-0.12 | updates-0.12 |
| 0.11.3 (Incubation) | http://download.eclipse.org/egit/updates-0.11 | updates-0.11 |
| 0.10.1 (Incubation) | http://download.eclipse.org/egit/updates-0.10 | updates-0.10 |
| 0.9.3 (Incubation) | http://download.eclipse.org/egit/updates-0.9 | updates-0.9 |
| 0.8.4 (Incubation) | http://download.eclipse.org/egit/updates-0.8 | updates-0.8 |