java - 获取 xls 中嵌入文件的文档名称（Apache POI）

Question

我想保存 .xls（POI 类型：HSSF）文件的所有嵌入文件，无论它是哪种嵌入文件类型。因此，如果我可以保存所有嵌入文件而无需扩展名，我会很高兴。我在 Java 7 上使用 Apache POI 库 3.7。

现在，我在使用createDocumentInputStream(document)时遇到了问题。我不知道如何获得这个预期的参数。谁能帮我？

public static void saveEmbeddedXLS(InputStream fis_param, String outputfile) throws IOException, InvalidFormatException{
    //HSSF - XLS

    int i = 0;
    System.out.println("Starting Embedded Search in xls...");

    POIFSFileSystem fs = new POIFSFileSystem(fis_param);//create FileSystem using fileInputStream
    HSSFWorkbook workbook = new HSSFWorkbook(fs);

    for (HSSFObjectData obj : workbook.getAllEmbeddedObjects()) {

        System.out.println("Objects : "+ obj.getOLE2ClassName());//the OLE2 Class Name of the object
        String oleName = obj.getOLE2ClassName();//Document Type

        DirectoryNode dn = (DirectoryNode) obj.getDirectory();//get Directory Node  


//Trying to create an input Stream with the embedded document, argument of createDocumentInputStream should be: String; Where/How can I get this correct parameter for the function?
        InputStream is = dn.createDocumentInputStream(oleName);//oleName = Document Type, but not it's name (Wrong!)

        FileOutputStream fos = new FileOutputStream(outputfile + "_" + i);//Outputfilepath + Number

        IOUtils.copy(is, fos);//FileInputStream > FileOutput Stream (save File without extension)
        i++;
       } 
    }