工具1：poi
　　poi是常用的读取office文件的开源工具。但是在它正式发布的版本中没有提供得到excel中formula值的功能。
　　这个poi还在开发中的功能。相关信息 请看http://jakarta.apache.org/poi/hssf/eval.html

　　工具2：jexcelapi
java excel api - a java api to read, write, and modify excel spreadsheets
http://jexcelapi.sourceforge.net/
目前的最新版本是2.6 

some features
* reads data from excel 95, 97, 2000, xp, and 2003 workbooks
* reads and writes formulas (excel 97 and later only)
* generates spreadsheets in excel 2000 format
* supports font, number and date formatting
* supports shading, bordering, and coloring of cells
* modifies existing worksheets
* is internationalized, enabling processing in almost any locale, country, language, or character encoding (formulas are currently only supported in english, french, * * spanish, and german, but more can be added if translated)
* supports copying of charts
* supports insertion and copying of images into spreadsheets
* supports logging with jakarta commons logging, log4j, jdk 1.4 logger, etc
...and much more