POI各Jar包的作用

目前POI的最新发布版本是3.10_FINAL.该版本保护的jar包有：

Maven artifactId	Prerequisites	JAR
poi	commons-logging, commons-codec, log4j	poi-version-yyyymmdd.jar
poi-scratchpad	poi	poi-scratchpad-version-yyyymmdd.jar
poi-ooxml	poi, poi-ooxml-schemas	poi-ooxml-version-yyyymmdd.jar
poi-ooxml-schemas	xmlbeans	poi-ooxml-schemas-version-yyyymmdd.jar
poi-examples	poi, poi-scratchpad, poi-ooxml	poi-examples-version-yyyymmdd.jar
ooxml-schemas	xmlbeans	ooxml-schemas-1.1.jar

很多人都困惑POI那么多Jar到底应该导入哪一个。

实际上很多时候我们只利用POI来操作Excel。甚至只用xls这一种格式。

那么就没有必要全部都导入了。具体应该使用哪个JAR包请参考以下内容：

Component Map

The Apache POI distribution consists of support for many document file formats. This support is provided in several Jar files. Not all of the Jars are needed for every format. The following tables show the relationships between POI components, Maven repository tags, and the project's Jar files.

Component	Application type	Maven artifactId	Notes
POIFS	OLE2 Filesystem	poi	Required to work with OLE2 / POIFS based files
HPSF	OLE2 Property Sets	poi
HSSF	Excel XLS	poi	For HSSF only, if common SS is needed see below
HSLF	PowerPoint PPT	poi-scratchpad
HWPF	Word DOC	poi-scratchpad
HDGF	Visio VSD	poi-scratchpad
HPBF	Publisher PUB	poi-scratchpad
HSMF	Outlook MSG	poi-scratchpad
OpenXML4J	OOXML	poi-ooxml plus one of poi-ooxml-schemas, ooxml-schemas	Only one schemas jar is needed, see below for differences
XSSF	Excel XLSX	poi-ooxml
XSLF	PowerPoint PPTX	poi-ooxml
XWPF	Word DOCX	poi-ooxml
Common SS	Excel XLS and XLSX	poi-ooxml	WorkbookFactory and friends all require poi-ooxml, not just core poi

当我们只要使用xls格式时、只要导入poi-version-yyyymmdd.jar就可以了。
当我们还要使用xlsx格式、还要导入poi-ooxml-version-yyyymmdd.jar。
至于poi-ooxml-schemas-version-yyyymmdd.jar这个jar基本不太会用到的。
当我们需要操作word、ppt、viso、outlook等时需要用到poi-scratchpad-version-yyyymmdd.jar。