如提到的此处

Refresh 分析源文件以检查是否从Eclipse外部进行了任何更改，如果是，则编译已更改的文件。

Refresh analyses the source-files to check if any changes were made from outside Eclipse, and if so, compiles files that were changed.

Clean 会删除所有编译类并强制重新编译整个项目（或工作区）。

Clean on the other hand removes all compiled classes and forces recompilation of the whole project (or workspace).