Reading a 10 MB file in Apache POI - java

The project that I'm working on is trying to read a very large Excel file (a couple hundred columns and around 3000 rows) and recognize patterns in a series of letters. It works just fine on smaller files, but when I try to run it using this file I receive a java.lang.OutOfMemoryError: Java heap space error even when I'm only trying to analyze the first few rows. The error appears to be at Workbook wb = WorkbookFactory.create(new File(filepath));
I've tried a few of the solutions on this website, but have not come across any success. My code is as follows:
import java.awt.List;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import org.apache.poi.EncryptedDocumentException;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class ExcelReader {
public int Reader(File file) throws IOException, EncryptedDocumentException, InvalidFormatException {
String filepath = file.getPath();
Workbook wb = WorkbookFactory.create(new File(filepath));
XSSFSheet sheet = (XSSFSheet) wb.getSheetAt(0);
XSSFRow row;
XSSFCell cell;
ArrayList<Integer> list = new ArrayList<Integer>();
int rows;
int cols = 0;
int temp = 0;
rows = sheet.getPhysicalNumberOfRows();
for (int i = 0; i <= 1; i++) {
row = sheet.getRow(i);
if (row != null) {
temp = sheet.getRow(i).getPhysicalNumberOfCells();
if (temp > cols)
cols = temp;
}
}
for (int r = 0; r <= 60; r++) {
row = sheet.getRow(r);
if (row != null) {
for (int c = 0; c <= cols; c++) {
int numblanks = 0;
cell = row.getCell((short) c);
if (cell != null) {
//System.out.print(cell + "\t\t");
} else {
//System.out.print("\t\t");
}
if (cell != null && cell.getCellType() == XSSFCell.CELL_TYPE_STRING) {
if ("N".equals(cell.getStringCellValue())) {
for (int k = c; k <= cols; k++) {
if ("-".equals(row.getCell(k).getStringCellValue())) {
numblanks++;
continue;
}
if ("S".equals(row.getCell(c + 2 + numblanks).getStringCellValue())
|| "T".equals(row.getCell(c + 2 + numblanks).getStringCellValue())) {
list.add((int) sheet.getRow(1).getCell(c).getNumericCellValue());
break;
}
}
}
}
}
System.out.println();
}
}
System.out.println();
System.out.println("Rows: " + rows);
System.out.println("Columns: " + cols);
System.out.println(list);
return temp;
}
}
Thank you for any help you can give me!

I solved this issue before. My case was to read a 23M Excel file which contains 230k rows.
Increase maximum heap size is not a good solution. Apache poi does not have a streaming mode to read data. This non-streaming mode costs too much memory.
My solution is to convert the data to xml and then use XMLReader to parse the data.
Please check the following sample code:
protected List<Entity> parseData(InputStream in) throws Exception {
OPCPackage pkg = OPCPackage.open(in);
XSSFReader r = new XSSFReader(pkg);
SharedStringsTable sst = r.getSharedStringsTable();
XMLReader parser = fetchSheetParser(sst);
XSSFReader.SheetIterator sheets = (XSSFReader.SheetIterator) r.getSheetsData();
while (sheets.hasNext()) {
InputStream sheet = sheets.next();
InputSource sheetSource = new InputSource(sheet);
parser.parse(sheetSource);
sheet.close();
break; // if only need to process one sheet.
}
return SheetHandler.getRawData();
}
private XMLReader fetchSheetParser(SharedStringsTable sst) throws SAXException {
XMLReader parser =
XMLReaderFactory.createXMLReader();
ContentHandler handler = new SheetHandler(sst);
parser.setContentHandler(handler);
return parser;
}
private static class SheetHandler extends DefaultHandler {
private SharedStringsTable sst;
private String lastContents;
private boolean nextIsString;
private boolean nextIsInlineString;
private boolean nextIsNull;
private SheetHandler(SharedStringsTable sst) {
this.sst = sst;
rawData = new ArrayList<Entity>();
}
public static List<Entity> getRawData() {
return rawData;
}
#Override
public void startElement(String uri, String localName, String name,
Attributes attributes) throws SAXException {
}
#Override
public void endElement(String uri, String localName, String name)
throws SAXException {
}
#Override
public void characters(char[] ch, int start, int length)
throws SAXException {
lastContents += new String(ch, start, length);
}
}
}

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Getting java.lang.NullPointerException while file exists on specified location

I am creating a test script using RestAssured, java & Selenium. I am trying to create multiple users using POST methods by using the data provided in users.xlsx file. I am getting the exception in my utils file given below:
package utils;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class ExcelUtils {
public static FileInputStream fis;
public static FileOutputStream fos;
public static XSSFWorkbook wb;
public static XSSFSheet ws;
public static XSSFRow row;
public static XSSFCell cell;
public static int getRowCount(String xlFile, String xlSheet) throws IOException {
fis = new FileInputStream(xlFile);
wb = new XSSFWorkbook (fis);
ws = wb.getSheet(xlSheet);
int row_count = ws.getLastRowNum();
wb.close();
fis.close();
return row_count;
}
public static int getCellCount(String xlFile, String xlSheet, int row_num) throws IOException {
fis = new FileInputStream(xlFile);
wb = new XSSFWorkbook(fis);
ws = wb.getSheet(xlSheet);
int cell_count = row.getLastCellNum();
wb.close();
fis.close();
return cell_count;
}
public static String getCellData(String xlFile, String xlSheet, int row_num, int column) throws IOException {
fis = new FileInputStream(xlFile);
wb = new XSSFWorkbook(fis);
ws = wb.getSheet(xlSheet);
row = ws.getRow(row_num);
cell= row.getCell(column);
String data;
try{
DataFormatter formatter = new DataFormatter();
String cellData = formatter.formatCellValue(cell);
return cellData;
}catch (Exception e){
data = "";
}
wb.close();
fis.close();
return data;
}
public static void setCellData(String xlFile, String xlSheet, int row_num, int column, String data) throws IOException {
fis = new FileInputStream(xlFile);
wb = new XSSFWorkbook(fis);
ws = wb.getSheet(xlSheet);
row = ws.getRow(row_num);
cell= row.getCell(column);
cell.setCellValue(data);
fos= new FileOutputStream(xlFile);
wb.write(fos);
wb.close();
fis.close();
fos.close();
}
}
This is my code under #DataProvider
#DataProvider(name = "createBulkUsers")
String[][] getUserData() throws IOException {
//Read data from excel
String path = "./src/test/testdata/users.xlsx";
int row_count = getRowCount(path, "Sheet1");
int col_count = getCellCount(path, "Sheet1", 1);
String userData[][] = new String[row_count][col_count];
for (int i = 1; i <= row_count ; i++) { // for rows
for (int j = 0; j < col_count; j++) { // for columns
userData [i-1][j] = getCellData(path, "Sheet1", i, j);
}
}
return userData ;
}
Please suggest.

extracting contents from csv using java

I need a java program that would extract info from a .csv file and run commands on a sql bank.
I've made a program that is working great so far, but I've made it to work with .xsl by mistake and can't make it to work with a csv file
here is the code:
package teste3;
import java.io.File;
import java.io.IOException;
import jxl.Cell;
import jxl.Sheet;
import jxl.Workbook;
import jxl.read.biff.BiffException;
public class Teste3 {
private String inputFile;
String[][] data = null;
String[][] user = null;
public void setInputFile(String inputFile)
{
this.inputFile = inputFile;
}
public String[][] read() throws IOException
{
File inputWorkbook = new File(inputFile);
Workbook w;
try
{
w = Workbook.getWorkbook(inputWorkbook);
Sheet sheet = w.getSheet(0);
data = new String[sheet.getColumns()][sheet.getRows()];
user = new String[sheet.getColumns()][sheet.getRows()];
int j = 11;
int a = 0;
sheet.getColumns();
{
for (int i = 1; i < sheet.getRows(); i++)
{
Cell cell = sheet.getCell(j, i);
data[0][i] = cell.getContents();
System.out.println(cell.getContents());
}
}
j= 9;
for (int i = 1; i < sheet.getRows(); i++)
{
Cell cell = sheet.getCell(j, i);
user[0][i] = cell.getContents();
System.out.println(user[0] [i]);
}
}
catch (BiffException e)
{
}
return data;
}
public static void main(String[] args) throws IOException
{
Teste3 test = new Teste3();
test.setInputFile("C:\\Users\\a0046059\\Documents\\teste.xls");
test.read();
}
}
the program is really simple because of my lack of skills.
Can anyone help me ?
Thank you.

Poi Formula evaluation Error

I am using poi-3.8-20120326.jar and Excel 2007, trying to collect all the cell value in one list.
I am using formula for date increment operation. For example: =(i2+3) for k2 cell.
While evaluating this formula through my java code returns #VALUE! (i2 is a date cell.)
Without source it's hard to guess what's wrong, but I think that are two things that you may forget.
1) FormulaEvaluator
2) DataFormatter
Take a look at example.
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.FormulaEvaluator;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
public class CellReader {
private Workbook workbook;
private DataFormatter formatter;
private FormulaEvaluator evaluator;
private void openWorkbook(String file) throws FileNotFoundException,
IOException, InvalidFormatException {
FileInputStream fis = null;
try {
fis = new FileInputStream(file);
workbook = WorkbookFactory.create(fis);
evaluator = workbook.getCreationHelper().createFormulaEvaluator();
formatter = new DataFormatter(true);
} finally {
if (fis != null) {
fis.close();
}
}
}
private void printXLSX() {
Sheet sheet = null;
Row row = null;
Cell cell = null;
int lastRowNum;
int lastCellNum;
sheet = workbook.getSheetAt(0);
lastRowNum = sheet.getLastRowNum();
for (int j = 0; j <= lastRowNum; j++) {
row = sheet.getRow(j);
if (row == null) {
continue;
}
lastCellNum = row.getLastCellNum();
for (int k = 0; k <= lastCellNum; k++) {
cell = row.getCell(k);
if (cell == null) {
continue;
}
if (cell.getCellType() != Cell.CELL_TYPE_FORMULA) {
System.out.println(formatter.formatCellValue(cell));
} else {
System.out.println(formatter.formatCellValue(cell,evaluator));
}
}
}
}
public static void main(String[] args) {
CellReader converter = null;
try {
converter = new CellReader();
converter.openWorkbook("a.xlsx");
converter.printXLSX();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}

Writing a large resultset to an Excel file using POI

This is sort of inline w/ Writing a large ResultSet to a File but the file in question is an Excel file.
I'm using the Apache POI library to write an Excel file with a large data set retrieved from a ResultSet object. The data could range from a few thousand records to about 1 million; not sure how this translates into file system bytes in Excel format.
The following is a test code I wrote to check out the time taken to write such a large result set and also the performance implication w.r.t CPU & Memory.
protected void writeResultsetToExcelFile(ResultSet rs, int numSheets, String fileNameAndPath) throws Exception {
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(fileNameAndPath));
int numColumns = rs.getMetaData().getColumnCount();
Workbook wb = ExcelFileUtil.createExcelWorkBook(true, numSheets);
Row heading = wb.getSheetAt(0).createRow(1);
ResultSetMetaData rsmd = rs.getMetaData();
for(int x = 0; x < numColumns; x++) {
Cell cell = heading.createCell(x+1);
cell.setCellValue(rsmd.getColumnLabel(x+1));
}
int rowNumber = 2;
int sheetNumber = 0;
while(rs.next()) {
if(rowNumber == 65001) {
log("Sheet " + sheetNumber + "written; moving onto to sheet " + (sheetNumber + 1));
sheetNumber++;
rowNumber = 2;
}
Row row = wb.getSheetAt(sheetNumber).createRow(rowNumber);
for(int y = 0; y < numColumns; y++) {
row.createCell(y+1).setCellValue(rs.getString(y+1));
wb.write(bos);
}
rowNumber++;
}
//wb.write(bos);
bos.close();
}
Not much luck with the above code. The file which is created seems to grow rapidly (~70Mb per sec). So I stopped the execution after about 10 minutes (killed the JVM when the file reaches 7Gb) and tried to open the file in Excel 2007. The moment I open it, the file size becomes 8k(!) and only the header and the first row are created. Not sure what I'm missing here.
Any ideas?
Using SXSSF poi 3.8
package example;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class SXSSFexample {
public static void main(String[] args) throws Throwable {
FileInputStream inputStream = new FileInputStream("mytemplate.xlsx");
XSSFWorkbook wb_template = new XSSFWorkbook(inputStream);
inputStream.close();
SXSSFWorkbook wb = new SXSSFWorkbook(wb_template);
wb.setCompressTempFiles(true);
SXSSFSheet sh = (SXSSFSheet) wb.getSheetAt(0);
sh.setRandomAccessWindowSize(100);// keep 100 rows in memory, exceeding rows will be flushed to disk
for(int rownum = 4; rownum < 100000; rownum++){
Row row = sh.createRow(rownum);
for(int cellnum = 0; cellnum < 10; cellnum++){
Cell cell = row.createCell(cellnum);
String address = new CellReference(cell).formatAsString();
cell.setCellValue(address);
}
}
FileOutputStream out = new FileOutputStream("tempsxssf.xlsx");
wb.write(out);
out.close();
}
}
It requires:
poi-ooxml-3.8.jar,
poi-3.8.jar,
poi-ooxml-schemas-3.8.jar,
stax-api-1.0.1.jar,
xml-apis-1.0.b2.jar,
xmlbeans-2.3.0.jar,
commons-codec-1.5.jar,
dom4j-1.6.1.jar
Useful link
Oh. I think you're writing the workbook out 944,000 times. Your wb.write(bos) call is in the inner loop. I'm not sure this is quite consistent with the semantics of the Workbook class? From what I can tell in the Javadocs of that class, that method writes out the entire workbook to the output stream specified. And it's gonna write out every row you've added so far once for every row as the thing grows.
This explains why you're seeing exactly 1 row, too. The first workbook (with one row) to be written out to the file is all that is being displayed - and then 7GB of junk thereafter.
Unless you have to write formulas or formatting you should consider writing out a .csv file. Infinitely simpler, infinitely faster, and Excel will do the conversion to .xls or .xlsx automatically and correctly by definition.
You can using SXSSFWorkbook implementation of Workbook, if you use style in your excel ,You can caching style by Flyweight Pattern to improve your performance.
You can increase the performance of excel export by following these steps:
1) When you fetch data from database, avoid casting the result set to the list of entity classes. Instead assign it directly to List
List<Object[]> resultList =session.createSQLQuery("SELECT t1.employee_name, t1.employee_id ... from t_employee t1 ").list();
instead of
List<Employee> employeeList =session.createSQLQuery("SELECT t1.employee_name, t1.employee_id ... from t_employee t1 ").list();
2) Create excel workbook object using SXSSFWorkbook instead of XSSFWorkbook and create new row using SXSSFRow when the data is not empty.
3) Use java.util.Iterator to iterate the data list.
Iterator itr = resultList.iterator();
4) Write data into excel using column++.
int rowCount = 0;
int column = 0;
while(itr.hasNext()){
SXSSFRow row = xssfSheet.createRow(rowCount++);
Object[] object = (Object[]) itr.next();
//column 1
row.setCellValue(object[column++]); // write logic to create cell with required style in setCellValue method
//column 2
row.setCellValue(object[column++]);
itr.remove();
}
5) While iterating the list, write the data into excel sheet and remove the row from list using remove method. This is to avoid holding unwanted data from the list and clear the java heap size.
itr.remove();
For now I took #Gian's advice & limited the number of records per Workbook to 500k and rolled over the rest to the next Workbook. Seems to be working decent. For the above configuration, it took me about 10 mins per workbook.
I updated BigGridDemo to support multiple sheets.
BigExcelWriterImpl.java
package com.gdais.common.apache.poi.bigexcelwriter;
import static com.google.common.base.Preconditions.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import org.apache.commons.io.FilenameUtils;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
public class BigExcelWriterImpl implements BigExcelWriter {
private static final String XML_ENCODING = "UTF-8";
#Nonnull
private final File outputFile;
#Nullable
private final File tempFileOutputDir;
#Nullable
private File templateFile = null;
#Nullable
private XSSFWorkbook workbook = null;
#Nonnull
private LinkedHashMap<String, XSSFSheet> addedSheets = new LinkedHashMap<String, XSSFSheet>();
#Nonnull
private Map<XSSFSheet, File> sheetTempFiles = new HashMap<XSSFSheet, File>();
BigExcelWriterImpl(#Nonnull File outputFile) {
this.outputFile = outputFile;
this.tempFileOutputDir = outputFile.getParentFile();
}
#Override
public BigExcelWriter createWorkbook() {
workbook = new XSSFWorkbook();
return this;
}
#Override
public BigExcelWriter addSheets(String... sheetNames) {
checkState(workbook != null, "workbook must be created before adding sheets");
for (String sheetName : sheetNames) {
XSSFSheet sheet = workbook.createSheet(sheetName);
addedSheets.put(sheetName, sheet);
}
return this;
}
#Override
public BigExcelWriter writeWorkbookTemplate() throws IOException {
checkState(workbook != null, "workbook must be created before writing template");
checkState(templateFile == null, "template file already written");
templateFile = File.createTempFile(FilenameUtils.removeExtension(outputFile.getName())
+ "-template", ".xlsx", tempFileOutputDir);
System.out.println(templateFile);
FileOutputStream os = new FileOutputStream(templateFile);
workbook.write(os);
os.close();
return this;
}
#Override
public SpreadsheetWriter createSpreadsheetWriter(String sheetName) throws IOException {
if (!addedSheets.containsKey(sheetName)) {
addSheets(sheetName);
}
return createSpreadsheetWriter(addedSheets.get(sheetName));
}
#Override
public SpreadsheetWriter createSpreadsheetWriter(XSSFSheet sheet) throws IOException {
checkState(!sheetTempFiles.containsKey(sheet), "writer already created for this sheet");
File tempSheetFile = File.createTempFile(
FilenameUtils.removeExtension(outputFile.getName())
+ "-sheet" + sheet.getSheetName(), ".xml", tempFileOutputDir);
Writer out = null;
try {
out = new OutputStreamWriter(new FileOutputStream(tempSheetFile), XML_ENCODING);
SpreadsheetWriter sw = new SpreadsheetWriterImpl(out);
sheetTempFiles.put(sheet, tempSheetFile);
return sw;
} catch (RuntimeException e) {
if (out != null) {
out.close();
}
throw e;
}
}
private static Function<XSSFSheet, String> getSheetName = new Function<XSSFSheet, String>() {
#Override
public String apply(XSSFSheet sheet) {
return sheet.getPackagePart().getPartName().getName().substring(1);
}
};
#Override
public File completeWorkbook() throws IOException {
FileOutputStream out = null;
try {
out = new FileOutputStream(outputFile);
ZipOutputStream zos = new ZipOutputStream(out);
Iterable<String> sheetEntries = Iterables.transform(sheetTempFiles.keySet(),
getSheetName);
System.out.println("Sheet Entries: " + sheetEntries);
copyTemplateMinusEntries(templateFile, zos, sheetEntries);
for (Map.Entry<XSSFSheet, File> entry : sheetTempFiles.entrySet()) {
XSSFSheet sheet = entry.getKey();
substituteSheet(entry.getValue(), getSheetName.apply(sheet), zos);
}
zos.close();
out.close();
return outputFile;
} finally {
if (out != null) {
out.close();
}
}
}
private static void copyTemplateMinusEntries(File templateFile,
ZipOutputStream zos, Iterable<String> entries) throws IOException {
ZipFile templateZip = new ZipFile(templateFile);
#SuppressWarnings("unchecked")
Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) templateZip.entries();
while (en.hasMoreElements()) {
ZipEntry ze = en.nextElement();
if (!Iterables.contains(entries, ze.getName())) {
System.out.println("Adding template entry: " + ze.getName());
zos.putNextEntry(new ZipEntry(ze.getName()));
InputStream is = templateZip.getInputStream(ze);
copyStream(is, zos);
is.close();
}
}
}
private static void substituteSheet(File tmpfile, String entry,
ZipOutputStream zos)
throws IOException {
System.out.println("Adding sheet entry: " + entry);
zos.putNextEntry(new ZipEntry(entry));
InputStream is = new FileInputStream(tmpfile);
copyStream(is, zos);
is.close();
}
private static void copyStream(InputStream in, OutputStream out) throws IOException {
byte[] chunk = new byte[1024];
int count;
while ((count = in.read(chunk)) >= 0) {
out.write(chunk, 0, count);
}
}
#Override
public Workbook getWorkbook() {
return workbook;
}
#Override
public ImmutableList<XSSFSheet> getSheets() {
return ImmutableList.copyOf(addedSheets.values());
}
}
SpreadsheetWriterImpl.java
package com.gdais.common.apache.poi.bigexcelwriter;
import java.io.IOException;
import java.io.Writer;
import java.util.Calendar;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.ss.util.CellReference;
class SpreadsheetWriterImpl implements SpreadsheetWriter {
private static final String XML_ENCODING = "UTF-8";
private final Writer _out;
private int _rownum;
SpreadsheetWriterImpl(Writer out) {
_out = out;
}
#Override
public SpreadsheetWriter closeFile() throws IOException {
_out.close();
return this;
}
#Override
public SpreadsheetWriter beginSheet() throws IOException {
_out.write("<?xml version=\"1.0\" encoding=\""
+ XML_ENCODING
+ "\"?>"
+
"<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">");
_out.write("<sheetData>\n");
return this;
}
#Override
public SpreadsheetWriter endSheet() throws IOException {
_out.write("</sheetData>");
_out.write("</worksheet>");
closeFile();
return this;
}
/**
* Insert a new row
*
* #param rownum
* 0-based row number
*/
#Override
public SpreadsheetWriter insertRow(int rownum) throws IOException {
_out.write("<row r=\"" + (rownum + 1) + "\">\n");
this._rownum = rownum;
return this;
}
/**
* Insert row end marker
*/
#Override
public SpreadsheetWriter endRow() throws IOException {
_out.write("</row>\n");
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, String value, int styleIndex)
throws IOException {
String ref = new CellReference(_rownum, columnIndex).formatAsString();
_out.write("<c r=\"" + ref + "\" t=\"inlineStr\"");
if (styleIndex != -1) {
_out.write(" s=\"" + styleIndex + "\"");
}
_out.write(">");
_out.write("<is><t>" + value + "</t></is>");
_out.write("</c>");
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, String value) throws IOException {
createCell(columnIndex, value, -1);
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, double value, int styleIndex)
throws IOException {
String ref = new CellReference(_rownum, columnIndex).formatAsString();
_out.write("<c r=\"" + ref + "\" t=\"n\"");
if (styleIndex != -1) {
_out.write(" s=\"" + styleIndex + "\"");
}
_out.write(">");
_out.write("<v>" + value + "</v>");
_out.write("</c>");
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, double value) throws IOException {
createCell(columnIndex, value, -1);
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, Calendar value, int styleIndex)
throws IOException {
createCell(columnIndex, DateUtil.getExcelDate(value, false), styleIndex);
return this;
}
#Override
public SpreadsheetWriter createCell(int columnIndex, Calendar value)
throws IOException {
createCell(columnIndex, value, -1);
return this;
}
}

How to read values from an excel file using Apache POI

I am currently working on a project for my computer science class, and I was trying to figure out how to retrieve and print certain values from a file in excel. Such as, how would I go about printing the integer in column J, row 6?
Better yet, is there a way for me to return the row number of a string in column 1? Such as, if I had a string "Phone" in column 1, could I use a command to return the row number of the first instance of "phone"?
I have looked at other questions, none of which sufficiently answered my own.
Here you go refer to this class file for iterating over an excel file
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.text.ParseException;
import java.util.Iterator;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class Test {
private static final String FILE_NAME = "/users/developer/Documents/myFile.xlsx";
public void employeesUpload() {
String fName = "";
String lName = "";
String phoneNumber = "";
String email = "";
String gender = "";
String employeeCode = "";
try {
FileInputStream excelFile = new FileInputStream(new File(FILE_NAME));
Workbook workbook = new XSSFWorkbook(excelFile);
Sheet datatypeSheet = workbook.getSheetAt(0);
Iterator<Row> iterator = datatypeSheet.iterator();
int rowIndex = 0;
DataFormatter formatter = new DataFormatter();
while (iterator.hasNext()) {
Row currentRow = iterator.next();
if (rowIndex > 0) {
Iterator<Cell> cellIterator = currentRow.iterator();
employeeCode = fName = lName = phoneNumber = email = gender = "";
int cellIndex = 0;
while (cellIndex <= 5) {
Cell currentCell = currentRow.getCell(cellIndex);
if (cellIndex == 4) {
employeeCode = formatter.formatCellValue(currentCell).trim();
}
if (cellIndex == 1) {
fName = formatter.formatCellValue(currentCell).trim();
}
if (cellIndex == 2) {
lName = formatter.formatCellValue(currentCell).trim();
}
if (cellIndex == 0) {
email = formatter.formatCellValue(currentCell);
email = email.trim().toLowerCase();
}
if (cellIndex == 3) {
phoneNumber = formatter.formatCellValue(currentCell).trim();
}
cellIndex++;
}
Cell resultCell = currentRow.getCell(7);
if (resultCell == null) {
resultCell = currentRow.createCell(7);
}
Cell employementIdCell = currentRow.getCell(8);
if (employementIdCell == null) {
employementIdCell = currentRow.createCell(8);
}
if (true) {
resultCell.setCellType(Cell.CELL_TYPE_STRING);
employementIdCell.setCellValue("Success");
resultCell.setCellValue(email);
} else {
resultCell.setCellType(Cell.CELL_TYPE_STRING);
resultCell.setCellValue("Error");
}
}
rowIndex++;
}
FileOutputStream outputStream = new FileOutputStream(FILE_NAME);
workbook.write(outputStream);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws ParseException, UnsupportedEncodingException {
Test employeesBulkUpload = new Test();
employeesBulkUpload.employeesUpload();
}
}
Hope this helps :)
user https://github.com/jueyue/easypoi this jar
use annotion to easy read excel
public class ExcelImportNewDateTest {
#Test
public void importTest() {
ImportParams params = new ImportParams();
params.setTitleRows(1);
params.setHeadRows(1);
long start = new Date().getTime();
List<NewDateEntity> list = ExcelImportUtil.importExcel(
new File(FileUtilTest.getWebRootPath("import/ExcelNewDateTest.xlsx")), NewDateEntity.class, params);
System.out.println(new Date().getTime() - start);
Assert.assertEquals(list.size(), 100);
System.out.println(list.size());
System.out.println(ReflectionToStringBuilder.toString(list.get(1)));
}
}

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