Develop Reference

Apache poi : setting custom properties at worksheet level using apache poi

public static void main(String[] args) {
try {
FileInputStream file = new FileInputStream(new File("D://New Microsoft Excel Worksheet.xlsx"));
XSSFWorkbook wb = new XSSFWorkbook(file);
XSSFSheet sheet = wb.createSheet("newsheet5");
CTWorksheet ctSheet = sheet.getCTWorksheet();
CTCustomProperties props = ctSheet.addNewCustomProperties();
props.addNewCustomPr().setId("APACHE POI");
props.addNewCustomPr().setName("Tender no = 48");
props.addNewCustomPr().setId("APACHE POI 2");
props.addNewCustomPr().setName("tender no = 58");
ctSheet.setCustomProperties(props);
FileOutputStream out = new FileOutputStream("D://New Microsoft Excel Worksheet.xlsx");
wb.write(out);
out.close();
wb.close();
} catch (Exception e) {
e.printStackTrace();
}
}
Xlsx file is corrupted after writing custom properties at sheet level.
I'm getting an error message as 'excel cannot open the file because the file format or file extension is not valid . Vefiry that the file has not been corrupted and the file extension matches the format of the file' when tried open the excel file.

Sheet custom properties only are useable using VBA. They are stored in the Excel file but the values are within binary document parts customProperty1.bin, customProperty2.bin, ... This is nothing what apache poi provides access to until now.
Using XSSF one needs creating the binary document part, then getting the relation Id to that binary document part. Then set CTCustomProperties - CTCustomProperty. There the Id points to the binary document part containing the value and the name is the property name.
Following complete example shows this. It is tested and works using current apache poi 4.1.2. It needs ooxml-schemas-1.4.jar being in class path because default poi-ooxml-schemas-4.1.2.jar does not contain all needed low level CT*-classes.
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.IOException;
import org.apache.poi.xssf.usermodel.*;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.*;
import org.apache.poi.openxml4j.opc.*;
import org.apache.poi.ooxml.POIXMLDocumentPart;
import java.nio.charset.StandardCharsets;
class CreateExcelSheetCustomProperties {
static void setSheetCustomProperty(XSSFSheet sheet, String customPropertyName, String customPropertyValue) throws Exception {
OPCPackage opcpackage = sheet.getWorkbook().getPackage();
int i = opcpackage.getUnusedPartIndex("/customProperty#.bin");
PackagePartName partname = PackagingURIHelper.createPartName("/customProperty" + i + ".bin");
PackagePart part = opcpackage.createPart(partname, "application/vnd.openxmlformats-officedocument.spreadsheetml.customProperty");
POIXMLDocumentPart customProperty = new POIXMLDocumentPart(part) {
#Override
protected void commit() throws IOException {
PackagePart part = getPackagePart();
OutputStream out = part.getOutputStream();
try {
out.write(customPropertyValue.getBytes(StandardCharsets.UTF_16LE));
out.close();
} catch (Exception ex) {
ex.printStackTrace();
};
}
};
String rId = sheet.addRelation(null, XSSFRelation.CUSTOM_PROPERTIES, customProperty).getRelationship().getId();
CTWorksheet ctSheet = sheet.getCTWorksheet();
CTCustomProperties props = ctSheet.getCustomProperties();
if (props == null) props = ctSheet.addNewCustomProperties();
CTCustomProperty prop = props.addNewCustomPr();
prop.setId(rId);
prop.setName(customPropertyName);
}
public static void main(String[] args) throws Exception {
try (XSSFWorkbook workbook = new XSSFWorkbook();
FileOutputStream fileout = new FileOutputStream("./Excel.xlsx") ) {
XSSFSheet sheet = workbook.createSheet();
setSheetCustomProperty(sheet, "APACHE POI", "Tender no = 48");
setSheetCustomProperty(sheet, "APACHE POI 2", "tender no = 58");
workbook.write(fileout);
}
}
}

I've been struggling with the same issue and found a way to make it work, but it's far from optimal. Here it is anyway and hopefully you or someone else can come up with a better method.
package temp.temp;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.poi.ooxml.POIXMLDocumentPart;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCustomProperties;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCustomProperty;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTWorksheet;
public class Temp2 {
public static void main(String[] args) {
File inputFile = new File("C:\\myspreadsheet.xlsx");
try (BufferedInputStream fis = new BufferedInputStream(new FileInputStream(inputFile))) {
XSSFWorkbook wb = new XSSFWorkbook(fis);
for (int i = 0; i < wb.getNumberOfSheets(); i++) {
XSSFSheet sheet = wb.getSheetAt(i);
System.out.println("\nSheetName=" + sheet.getSheetName());
CTWorksheet ctSheet = sheet.getCTWorksheet();
CTCustomProperties props = ctSheet.getCustomProperties();
if (props != null) {
List<CTCustomProperty> propList = props.getCustomPrList();
propList.stream().forEach((prop) -> {
POIXMLDocumentPart rel = sheet.getRelationById(prop.getId());
if (rel != null) {
try (InputStream inp = rel.getPackagePart().getInputStream()) {
byte[] inBytes = inp.readAllBytes();
// By experimentation, byte array has two bytes per character with least
// significant in first byte which is UTF-16LE encoding. Don't know why!
String value = new String(inBytes, "UTF-16LE");
System.out.println(" " + prop.getName() + "=" + value);
} catch (IOException ioe) {
//Error
}
}
});
}
}
wb.close();
} catch (Exception e) {
System.out.println(e);
}
System.out.println("End");
}
}
Note that CTWorksheet comes from poi-ooxml-schemas-xx.jar and CustomProperties from ooxml-schemas-yy.jar, so both have to be on the classpath. If you're using modules (as I am), this gives big problems! Good Luck

Read Excel and get the row number and file extension for embedded objects

I am using Apache POI with Java 1.8 in my application. In my application, I try to read Excel and get the embedded objects.
I need to know how to get the row number and file extensions for each embedded OLE object.
Workbook workbook = WorkbookFactory.create(new File(path));
XSSFWorkbook fWorkbook = (XSSFWorkbook) workbook;
List<PackagePart> embeddedDocs = fWorkbook.getAllEmbedds();
To get embeddedDocs.getContentType Which returns the application/vnd.openxmlformats-officedocument.oleObject.
But is there anyway where we can get the file extensions (i.e pdf,ppt,mp3) as which is returned by the MimeType. And which way to get row number of embedded objects. Any ideas / Coding logic to resolve this will be very useful.

The following is working for - I guess - the usual suspects. I've tested it with .xls/x on the POI trunk, which will be POI 4.1.0, but should work with POI 4.0.1 too.
Known issues are:
an object wasn't embedded based on a file, then you don't get a filename. This probably also applies to most .xls files.
a .xlsx only contains a vmlDrawing*.xml, then the DrawingPatriach can't be extracted and no shapes can be determined
a shape in a .xlsx wasn't anchored via twoCellAnchor, then you don't get a ClientAnchor
Code:
import java.io.FileInputStream;
import java.io.IOException;
import org.apache.poi.hpsf.ClassIDPredefined;
import org.apache.poi.poifs.filesystem.DirectoryEntry;
import org.apache.poi.ss.usermodel.ChildAnchor;
import org.apache.poi.ss.usermodel.ClientAnchor;
import org.apache.poi.ss.usermodel.Drawing;
import org.apache.poi.ss.usermodel.ObjectData;
import org.apache.poi.ss.usermodel.Shape;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.junit.Test;
public class TestEmbed {
#Test
public void extract() throws IOException {
// String xlsName = "test-data/spreadsheet/WithEmbeddedObjects.xls";
String xlsName = "embed.xlsx";
try (FileInputStream fis = new FileInputStream(xlsName);
Workbook xls = WorkbookFactory.create(fis)) {
for (Sheet s : xls) {
Drawing<?> dp = s.getDrawingPatriarch();
if (dp != null) {
for (Shape sh : dp) {
if (sh instanceof ObjectData) {
ObjectData od = (ObjectData)sh;
String filename = od.getFileName();
String ext = null;
if (filename != null && !filename.isEmpty()) {
int i = filename.lastIndexOf('.');
ext = (i > 0) ? filename.substring(i) : ".bin";
} else {
String ct = null;
try {
DirectoryEntry de = od.getDirectory();
if (de != null) {
ClassIDPredefined ctcls = ClassIDPredefined.lookup(de.getStorageClsid());
if (ctcls != null) {
ext = ctcls.getFileExtension();
}
}
} catch (Exception ignore) {
}
}
if (ext == null) {
ext = ".bin";
}
ChildAnchor chAnc = sh.getAnchor();
if (chAnc instanceof ClientAnchor) {
ClientAnchor anc = (ClientAnchor) chAnc;
System.out.println("Rows: " + anc.getRow1() + " to " + anc.getRow2() + " - filename: "+filename+" - ext: "+ext);
}
}
}
}
}
}
}
}

gettting exception while reading duplicate column name excel file using sparkexcel library. How to overcome this issue

I am using spark-excel(com.crealytics.spark.excel) library to read excel file. If no duplicate column in excel file, the library working fine. If any duplicate column name occurs in excel file, throwing below exception.
How to overcome this error?
Is there any workaround solution to overcome this?
Exception in thread "main" org.apache.spark.sql.AnalysisException: Found duplicate column(s) in the data schema: `net territory`;
at org.apache.spark.sql.util.SchemaUtils$.checkColumnNameDuplication(SchemaUtils.scala:85)

Using spark excel API getting exception .
StructType schema = DataTypes.createStructType(new StructField[]{DataTypes.createStructField("CGISAI", DataTypes.StringType, true), DataTypes.createStructField("SALES TERRITORY", DataTypes.StringType, true)});
SQLContext sqlcxt = new SQLContext(jsc);
Dataset<Row> df = sqlcxt.read()
.format("com.crealytics.spark.excel")
.option("path", "file:///"+siteinfofile)
.option("useHeader", "true")
.option("spark.read.simpleMode", "true")
.option("treatEmptyValuesAsNulls", "true")
.option("inferSchema", "false")
.option("addColorColumns", "False")
.option("sheetName", "sheet1")
.option("startColumn", 22)
.option("endColumn", 23)
//.schema(schema)
.load();
return df;
This is the code I am using. I am using sparkexcel library from com.crealytics.spark.excel.
I want the solution to identify whether excel file has duplicate columns or not. if have duplicate columns, how to rename/eliminate the duplicate columns.
WorkAround is as below:
convert .xlsx file into .csv . using spark default csv api that can handle duplicate column names by renaming them automatically.
Below is the code to convert from xlsx to csv file.
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.huawei.java.tools;
/**
*
* #author Nanaji Jonnadula
*/
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackageAccess;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.util.CellAddress;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.util.SAXHelper;
import org.apache.poi.xssf.eventusermodel.ReadOnlySharedStringsTable;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler;
import org.apache.poi.xssf.model.StylesTable;
import org.apache.poi.xssf.usermodel.XSSFComment;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import javax.xml.parsers.ParserConfigurationException;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import static org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler.SheetContentsHandler;
public class ExcelXlsx2Csv {
private static class SheetToCSV implements SheetContentsHandler {
private boolean firstCellOfRow = false;
private int currentRow = -1;
private int currentCol = -1;
private StringBuffer lineBuffer = new StringBuffer();
/** * Destination for data */
private FileOutputStream outputStream;
public SheetToCSV(FileOutputStream outputStream) {
this.outputStream = outputStream;
}
#Override
public void startRow(int rowNum) {
/** * If there were gaps, output the missing rows: * outputMissingRows(rowNum - currentRow - 1); */
// Prepare for this row
firstCellOfRow = true;
currentRow = rowNum;
currentCol = -1;
lineBuffer.delete(0, lineBuffer.length()); //clear lineBuffer
}
#Override
public void endRow(int rowNum) {
lineBuffer.append('\n');
try {
outputStream.write(lineBuffer.substring(0).getBytes());
} catch (IOException e) {
System.out.println("save date to file error at row number: {}"+ currentCol);
throw new RuntimeException("save date to file error at row number: " + currentCol);
}
}
#Override
public void cell(String cellReference, String formattedValue, XSSFComment comment) {
if (firstCellOfRow) {
firstCellOfRow = false;
} else {
lineBuffer.append(',');
}
// gracefully handle missing CellRef here in a similar way as XSSFCell does
if (cellReference == null) {
cellReference = new CellAddress(currentRow, currentCol).formatAsString();
}
int thisCol = (new CellReference(cellReference)).getCol();
int missedCols = thisCol - currentCol - 1;
if (missedCols > 1) {
lineBuffer.append(',');
}
currentCol = thisCol;
if (formattedValue.contains("\n")) {
formattedValue = formattedValue.replace("\n", "");
}
formattedValue = "\"" + formattedValue + "\"";
lineBuffer.append(formattedValue);
}
#Override
public void headerFooter(String text, boolean isHeader, String tagName) {
// Skip, no headers or footers in CSV
}
}
private static void processSheet(StylesTable styles, ReadOnlySharedStringsTable strings,
SheetContentsHandler sheetHandler, InputStream sheetInputStream) throws Exception {
DataFormatter formatter = new DataFormatter();
InputSource sheetSource = new InputSource(sheetInputStream);
try {
XMLReader sheetParser = SAXHelper.newXMLReader();
ContentHandler handler = new XSSFSheetXMLHandler(
styles, null, strings, sheetHandler, formatter, false);
sheetParser.setContentHandler(handler);
sheetParser.parse(sheetSource);
} catch (ParserConfigurationException e) {
throw new RuntimeException("SAX parser appears to be broken - " + e.getMessage());
}
}
public static void process(String srcFile, String destFile,String sheetname_) throws Exception {
File xlsxFile = new File(srcFile);
OPCPackage xlsxPackage = OPCPackage.open(xlsxFile.getPath(), PackageAccess.READ);
ReadOnlySharedStringsTable strings = new ReadOnlySharedStringsTable(xlsxPackage);
XSSFReader xssfReader = new XSSFReader(xlsxPackage);
StylesTable styles = xssfReader.getStylesTable();
XSSFReader.SheetIterator iter = (XSSFReader.SheetIterator) xssfReader.getSheetsData();
int index = 0;
while (iter.hasNext()) {
InputStream stream = iter.next();
String sheetName = iter.getSheetName();
System.out.println(sheetName + " [index=" + index + "]");
if(sheetName.equals(sheetname_)){
FileOutputStream fileOutputStream = new FileOutputStream(destFile);
processSheet(styles, strings, new SheetToCSV(fileOutputStream), stream);
fileOutputStream.flush();
fileOutputStream.close();
}
stream.close();
++index;
}
xlsxPackage.close();
}
public static void main(String[] args) throws Exception {
ExcelXlsx2Csv.process("D:\\data\\latest.xlsx", "D:\\data\\latest.csv","sheet1"); //source , destination, sheetname
}
}

Error in opening an mail attached excel file created using Apache POI

I am creating an excel sheet using Apache POI and then sending the same file using Java GWT.The file created is all right.Now in the mail there are two options- Save or open.When I save the file in machine it is working fine but when I try to open ,it opens in notepad.In the suggestion too it is not showing excel. Here is my code to create the excel sheet:
package com.ericsson.egi.sxs.utils;
import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import com.ericsson.egi.sxs.persistence.entity.AssetOrder;
public class CreateExcelFile {
int rownum = 0;
HSSFSheet firstSheet;
Collection<File> files;
HSSFWorkbook workbook;
CreateExcelFile() {
}
public File createWeeklyReport(List<AssetOrder> tempOrderList) throws Exception {
workbook = new HSSFWorkbook();
firstSheet = workbook.createSheet("FIRST SHEET");
List<String> headerRow = new ArrayList<String>();
headerRow.add("Name of Supplier/Vendor");
headerRow.add("Description of Contract");
headerRow.add("Initiator");
headerRow.add("Type Of Contract");
headerRow.add("Template Source");
headerRow.add("Savings");
headerRow.add("Payment Term");
headerRow.add("Code of Conduct Signed by Supplier");
headerRow.add("RoHS clause Included");
headerRow.add("Agreement No");
headerRow.add("Agreement Validity From ");
headerRow.add("Agreement Validity To");
headerRow.add("Sanctioned Parties List Screening");
headerRow.add("Sanctioned Parties List Screening Reasons in case no answer NO");
headerRow.add("Registered in CLM");
headerRow.add("Registered in CLM reasons if answer NO");
headerRow.add("Current State");
headerRow.add("Next State");
headerRow.add("TAT for L1");
headerRow.add("TAT for L2");
headerRow.add("TAT for L3");
headerRow.add("TAT for L4");
headerRow.add("Current State Comments");
List<List> recordToAdd = new ArrayList<List>();
recordToAdd.add(headerRow);
for (AssetOrder order : tempOrderList ) {
List<String> row = new ArrayList<String>();
row.add(order.getSourcingDetails().getVendorName());
row.add(order.getSourcingDetails().getContractDescription());
row.add(order.getSourcingDetails().getInitiatorName());
row.add(order.getSourcingDetails().getContractType());
row.add(order.getSourcingDetails().getTemplateSource());
row.add(order.getSourcingDetails().getSavings());
row.add(order.getSourcingDetails().getPaymentTerm());
if (order.getSourcingDetails().getIsCOCSigned()) {
row.add("YES");
} else {
row.add("NO");
}
if (order.getSourcingDetails().getIsROHSIncluded()) {
row.add("YES");
} else {
row.add("NO");
}
row.add(order.getSourcingDetails().getAgreementNo());
row.add(order.getSourcingDetails().getValidityFrom().toString());
row.add(order.getSourcingDetails().getValidityTo().toString());
if (order.getSourcingDetails().getIsSPLScreening()) {
row.add("YES");
} else {
row.add("NO");
}
row.add(order.getSourcingDetails().getReasonsForSPL());
if (order.getSourcingDetails().getIsRegisteredInCLM()) {
row.add("YES");
} else {
row.add("NO");
}
row.add(order.getSourcingDetails().getReasonsForCLM());
row.add(order.getStatusMaster().getStatusName());
row.add(null);
row.add(null);
row.add(null);
row.add(null);
row.add(null);
row.add(order.getComments());
recordToAdd.add(row);
}
CreateExcelFile cls = new CreateExcelFile(recordToAdd);
File file = cls.createExcelFile(tempOrderList.get(0).getOrderRequesterSignum());
return file;
}
File createExcelFile(String requesterSignum) {
FileOutputStream fos = null;
File file = new File("/tmp/" + requesterSignum + "_StatusReport.xls");
try {
fos=new FileOutputStream(file);
HSSFCellStyle hsfstyle=workbook.createCellStyle();
hsfstyle.setBorderBottom((short) 1);
hsfstyle.setFillBackgroundColor((short)245);
workbook.write(fos);
} catch (Exception e) {
e.printStackTrace();
}
return file;
}
CreateExcelFile(List<List> l1) throws Exception {
try {
workbook = new HSSFWorkbook();
firstSheet = workbook.createSheet("FIRST SHEET");
for (int j = 0; j < l1.size(); j++) {
Row row = firstSheet.createRow(rownum);
List<String> l2= l1.get(j);
for(int k=0; k<l2.size(); k++)
{
Cell cell = row.createCell(k);
cell.setCellValue(l2.get(k));
}
rownum++;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
}

Try with other Excel Extension as per your Excel version installed on your machine.
--EDIT--
May be the issue is related to Content Type. Please confirm what are you using for this?
response.setContentType("APPLICATION/OCTET-STREAM");
// try this one if above doesn't work
//response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-disposition", "attachment;filename=myExcel.xls");

Read embedded Object in excel using java

I want to make one excel sheet which I need to send other for filling it.
In the excel sheet , the other person fill his information and can also attach text/doc file with excel sheet....
I need to access that text/doc file .. Please provide me a solution .
I am using Apache POI - HSSF api.
Thanks in advance.
package excelExchange;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Iterator;
import java.util.Vector;
import org.apache.poi.hslf.HSLFSlideShow;
import org.apache.poi.hslf.usermodel.SlideShow;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFObjectData;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hwpf.HWPFDocument;
import org.apache.poi.poifs.filesystem.DirectoryNode;
//import org.apache.poi.h;
import org.apache.poi.poifs.filesystem.*;
public class ReadEmbeddedObject {
public static void main(String[] args) throws IOException {
String fileName = "C:\\Mayur\\NewsLetter\\files\\projectInfo.xls";
//Vector dataHolder =
ReadCSV(fileName);
}
public static void ReadCSV(String fileName) throws IOException{
Vector cellVectorHolder = new Vector();
FileInputStream myInput = new FileInputStream(fileName);
// myFileSystem=fs
//myWorkBook=workbook
POIFSFileSystem fs = new POIFSFileSystem(myInput);
HSSFWorkbook workbook = new HSSFWorkbook(fs);
for (HSSFObjectData obj : workbook.getAllEmbeddedObjects()) {
//the OLE2 Class Name of the object
System.out.println("Objects : "+ obj.getOLE2ClassName()+ " 2 .");
String oleName = obj.getOLE2ClassName();
if (oleName.equals("Worksheet")) {
System.out.println("Worksheet");
DirectoryNode dn = (DirectoryNode) obj.getDirectory();
HSSFWorkbook embeddedWorkbook = new HSSFWorkbook(dn, fs, false);
System.out.println(oleName+": " + embeddedWorkbook.getNumberOfSheets());
System.out.println("Information :--- ");
System.out.println(" name " + embeddedWorkbook.getSheetName(0));
//System.out.println(entry.getName() + ": " + embeddedWorkbook.getNumberOfSheets());
} else if (oleName.equals("Document")) {
System.out.println("Document");
DirectoryNode dn = (DirectoryNode) obj.getDirectory();
HWPFDocument embeddedWordDocument = new HWPFDocument(dn,fs);
System.out.println("Doc : " + embeddedWordDocument.getRange().text());
} else if (oleName.equals("Presentation")) {
System.out.println("Presentation");
DirectoryNode dn = (DirectoryNode) obj.getDirectory();
SlideShow embeddedPowerPointDocument = new SlideShow(new HSLFSlideShow(dn, fs));
//Entry entry = (Entry) entries.next();
System.out.println(": " + embeddedPowerPointDocument.getSlides().length);
} else {
System.out.println("Else part ");
if(obj.hasDirectoryEntry()){
// The DirectoryEntry is a DocumentNode. Examine its entries to find out what it is
DirectoryNode dn = (DirectoryNode) obj.getDirectory();
for (Iterator entries = dn.getEntries(); entries.hasNext();) {
Entry entry = (Entry) entries.next();
System.out.println(oleName + "." + entry.getName());
}
} else {
// There is no DirectoryEntry
// Recover the object's data from the HSSFObjectData instance.
byte[] objectData = obj.getObjectData();
}
}
}
}
}
</code>

POI has APIs to iterate over embedded objects. (HSSFWorkbook .getAllEmbeddedObjects or XSSFWorkbook.getAllEmbedds ). Examples here http://poi.apache.org/spreadsheet/quick-guide.html#Embedded

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.ArrayList;
/**
* Demonstrates how you can extract embedded data from a .xlsx file
*/
public class GetEmbedded {
public static void main(String[] args) throws Exception {
String path = "SomeExcelFile.xlsx"
XSSFWorkbook workbook = new XSSFWorkbook(new FileInputStream(new File(path)));
for (PackagePart pPart : workbook.getAllEmbedds()) {
String contentType = pPart.getContentType();
if (contentType.equals("application/vnd.ms-excel")) { //This is to read xls workbook embedded to xlsx file
HSSFWorkbook embeddedWorkbook = new HSSFWorkbook(pPart.getInputStream());
int countOfSheetXls=embeddedWorkbook.getNumberOfSheets();
}
else if (contentType.equals("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")) { //This is to read xlsx workbook embedded to xlsx file
if(pPart.getPartName().getName().equals("/xl/embeddings/Microsoft_Excel_Worksheet12.xlsx")){
//"/xl/embeddings/Microsoft_Excel_Worksheet12.xlsx" - Can read an Excel from a particular sheet
// This is the worksheet from the Parent Excel-sheet-12
XSSFWorkbook embeddedWorkbook = new XSSFWorkbook(pPart.getInputStream());
int countOfSheetXlsx=embeddedWorkbook.getNumberOfSheets();
ArrayList<String> sheetNames= new ArrayList<String>();
for(int i=0;i<countOfSheetXlsx;i++){
String name=workbook.getSheetName(i);
sheetNames.add(name);
}
}
}
}
}
}