IPath IFile IProject IWorkspace
String filePath = "\testP\src\context\test.html";
IPath path = new Path(filePath);
IWorkspaceRoot = root = ResourcesPlugin.getWorkspace().getRoot();
IProject ps[] = root.getProjects();
org.eclipse.core.resources.IFile
file = root.getFileForLocation(path
);
IProject = file.getProject();
root 是整個Workspace的根容器，它可以獲取到子目錄的文件。
和java.io.File不同的是IFile通常是get出來的，不是new出來的。
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