java读取excel文件

使用到的包： poi-ooxml-3.14.jar;  poi-ooxml.jar;

1. 在网上查找相关文件，最多的答案就是使用 HSSFWorkbook 进行读取：　　

POIFSFileSystem poifsFileSystem = new POIFSFileSystem(new FileInputStream(file));
HSSFWorkbook workbook = new HSSFWorkbook(poifsFileSystem);

　结果：对xlsx文件识别不了；

2.专门针对xlsx文件找解决方案，得到用 XSSFWorkbook 进行处理；　　　　

XSSFWorkbook workbook = new XSSFWorkbook(new BufferedInputStream(stream)); 

　结果：可以识别xlsx文件；

3.需要对文件进行判定，什么情况用 HSSFWorkbook，什么情况下用XSSFWorkbook 

if(!inp.markSupported())
　　inp = new PushbackInputStream(inp, 8);
if(NPOIFSFileSystem.hasPOIFSHeader(IOUtils.peekFirst8Bytes(inp))){
　　NPOIFSFileSystem fs = new NPOIFSFileSystem(inp);
}else if(POIXMLDocument.hasOOXMLHeader(inp))
　　return new XSSFWorkbook(OPCPackage.open(inp));
else
　　throw new InvalidFormatException("你的excel版本目前poi解析不了");

　ok，看似完美解决问题，但其实在WorkbookFactory里已经有了对excel 的相关操作方法

4. 借用工具类 WorkbookFactory　　

/** 
 * Creates the appropriate HSSFWorkbook / XSSFWorkbook from 
 *  the given InputStream. 
 * Your input stream MUST either support mark/reset, or 
 *  be wrapped as a {@link PushbackInputStream}! 
 */  
 public static Workbook create(InputStream inp) throws IOException, InvalidFormatException {  
    // If clearly doesn't do mark/reset, wrap up  
    if(! inp.markSupported()) {  
        inp = new PushbackInputStream(inp, 8);  
    }  
          
    if(POIFSFileSystem.hasPOIFSHeader(inp)) {  
        return new HSSFWorkbook(inp);  
    }  
    if(POIXMLDocument.hasOOXMLHeader(inp)) {  
        return new XSSFWorkbook(OPCPackage.open(inp));  
    }  
    throw new IllegalArgumentException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");  
  }  

5. 终极版　

Workbook workbook = WorkbookFactory.create(new FileInputStream(file));

　一行代码搞定，^_^；