Cannot complete the install because one or more required items could not be found解决办法

Eclipse安装springide，出现如下所示的错误：

Cannot complete the install because one or more required items could not be found.
  Software being installed: Spring IDE Security Extension (optional) 3.7.3.201602250914-RELEASE (org.springframework.ide.eclipse.security.feature.feature.group 3.7.3.201602250914-RELEASE)
  Missing requirement: Spring IDE Live Beans Graph 3.7.3.201602250914-RELEASE (org.springframework.ide.eclipse.beans.ui.livegraph 3.7.3.201602250914-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) 3.7.3.201602250914-RELEASE (org.springframework.ide.eclipse.feature.feature.group 3.7.3.201602250914-RELEASE)
    To: org.springframework.ide.eclipse.beans.ui.livegraph [3.7.3.201602250914-RELEASE]
  Cannot satisfy dependency:
    From: Spring IDE Security Extension (optional) 3.7.3.201602250914-RELEASE (org.springframework.ide.eclipse.security.feature.feature.group 3.7.3.201602250914-RELEASE)
    To: org.springframework.ide.eclipse.feature.feature.group 0.0.0

解决办法：Window->Preferences->Install/Update->Available Software Sites->Add:

Name:GEF
Location:http://download.eclipse.org/tools/gef/updates/releases/

再次安装springide即可成功。