国外网站（http://stackoverflow.com/questions/969782/eclipses-local-history-where-are-files-saved）上：
Every time you modify a file in Eclipse, a copy of the old contents is kept in the local history. At any time, you can compare or replace a file with any older version from the history.
Although this is no replacement for a real code repository, it can help you out when you change or delete a file by accident.
Local history also has an advantage that it wasn’t really designed for: The history can also help you out when your workspace has a catastrophic problem or if you get disk errors that corrupt your workspace files.
As a last resort, you can manually browse the local history folder to find copies of the files you lost, which is a bit like using Google’s cache to browse Web pages that no longer exist.
Each file revision is stored in a separate file with a random file name inside the history folder. The path of the history folder inside your workspace is
.metadata/.plugins/org.eclipse.core.resources/.history/
You can use your operating system’s search tool to locate the files you are looking for.
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Note, if your need to import your local history into a new workspace, you will need both:
.metadata/.plugins/org.eclipse.core.resources/.history
.metadata/.plugins/org.eclipse.core.resources/.project
to have a functional local history in that new workspace.
Eclipse中在导入已有项目时如何将Local History一起导入到新workspace的呢？
如果公司和家里的机器都可以共享这些history文件，这样我们就可以在不同地点同样的查看我们的历史记录，那该多好啊。。。
事实上，我们只要知道eclipse将history记录存到了什么文件中，又放在什么位置就可以了，然后我们就只需要将这个history记录拷贝到新的工作空间中就ok！
根据上面国外的回帖好像是
%eclipse%\workspace\.metadata\.plugins\org.eclipse.core.resources\.history