eclipse安装STS插件失败

使用Eclipse Neon安装Spring Tool Suite报错：

安装STS插件时，停止到49%总会报错，无论重复安装多少次，都是同样的步骤。

Cannot complete the install because one or more required items could not be found.
  Software being installed: Spring IDE OSGi Extension (optional) 3.8.3.201612191259-RELEASE (org.springframework.ide.eclipse.osgi.feature.feature.group 3.8.3.201612191259-RELEASE)
  Missing requirement: Spring IDE Live Beans Graph 3.8.3.201612191259-RELEASE (org.springframework.ide.eclipse.beans.ui.livegraph 3.8.3.201612191259-RELEASE) requires 'bundle org.eclipse.zest.core [1.0.0,2.0.0)' but it could not be found
  Cannot satisfy dependency:
    From: Spring IDE Core (required) 3.8.3.201612191259-RELEASE (org.springframework.ide.eclipse.feature.feature.group 3.8.3.201612191259-RELEASE)
    To: org.springframework.ide.eclipse.beans.ui.livegraph [3.8.3.201612191259-RELEASE]
  Cannot satisfy dependency:
    From: Spring IDE OSGi Extension (optional) 3.8.3.201612191259-RELEASE (org.springframework.ide.eclipse.osgi.feature.feature.group 3.8.3.201612191259-RELEASE)
    To: org.springframework.ide.eclipse.feature.feature.group 0.0.0

原因是没有安装STS依赖的GEF插件
解决办法：
启动eclipse，点击window——>preferences——>install/update——>available software sites，点击Add
添加如下信息：
GEF

http://download.eclipse.org/tools/gef/updates/releases/
安装GEF插件

然后再重新安装sts插件