This excel chart viewer portlet was developed by XTIVIA, the 2012 Liferay North America Partner of the Year, using Apache POI and a choice charting libraries including Google Charts, FusionCharts, and AnyChart. In the portlet, users can easily configure the data source using Excel files uploaded in the Liferay document library, the data range inside the Excel file and the chart type to be rendered. Multiple instances of this portlet can be added to the portal with each instance configured to point to different Excel files, different worksheets and different cell ranges.

Refer to the following resources to get started with this portlet:
http://blogs.xtivia.com/excel-chart-portlet