Java Misc

In Java, reading excel file is not similar to read word file because of cells in excel file. JDK does not provide direct API to read or write Microsoft Excel or Word document. We have to rely on the third-party library that is Apache POI.

What is Apache POI?

Apache POI (Poor Obfuscation Implementation) is a Java API for reading and writing Microsoft Documents in both formats .xls and .xlsx. It contains classes and interfaces. The Apache POI library provides two implementations for reading excel files:

HSSF (Horrible SpreadSheet Format) Implementation: It denotes an API that is working with Excel 2003 or earlier versions.
XSSF (XML SpreadSheet Format) Implementation: It denotes an API that is working with Excel 2007 or later versions.

Interfaces and Classes in Apache POI

Interfaces

Workbook: It represents an Excel Workbook. It is an interface implement by HSSFWorkbook and XSSFWorkbook.
Sheet: It is an interface that represents an Excel worksheet. A sheet is a central structure of a workbook, which represents a grid of cells. The Sheet interface extends java.lang.Iterable.
Row: It is also an interface that represents the row of the spreadsheet. The Row interface extends java.lang.Iterable. There are two concrete classes: HSSFRow and XSSFRow.
Cell: It is an interface. It is a high-level representation of a cell in a row of the spreadsheet. HSSFCell and XSSFCell implement Cell interface.

Classes

XLS Classes

HSSFWorkbook: It is a class representing the XLS file.
HSSFSheet: It is a class representing the sheet in an XLS file.
HSSFRow: It is a class representing a row in the sheet of XLS file.
HSSFCell: It is a class representing a cell in a row of XLS file.

XLSX Classes

XSSFWorkbook: It is a class representing the XLSX file.
XSSFSheet: It is a class representing the sheet in an XLSX file.
XSSFRow: It is a class representing a row in the sheet of XLSX file.
XSSFCell: It is a class representing a cell in a row of XLSX file.

Steps to read data from XLS file

Step 1: Create a simple Java project in eclipse.

Step 2: Now, create a lib folder in the project.

Step 3: Download and add the following jar files in the lib folder:

commons-collections4-4.1.jar Click Here
poi-3.17.jar Click Here
poi-ooxml-3.17.jar Click Here
poi-ooxml-schemas-3.17.jar Click Here
xmlbeans-2.6.0.jar Click Here

Step 4: Set the Class Path:

Right-click on the project ->Build Path ->Add External JARs -> select all the above jar files -> Apply and close.

Step 5: Now create a class file with the name ReadExcelFileDemo and write the following code in the file.

Step 6: Create an excel file with the name "student.xls" and write some data into it.

Step 7: Save and run the program.

Example of reading excel file (.xls) file

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
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.FormulaEvaluator;
import org.apache.poi.ss.usermodel.Row;
public class ReadExcelFileDemo
{
public static void main(String args[]) throws IOException
{
//obtaining input bytes from a file
FileInputStream fis=new FileInputStream(new File("C:\\demo\\student.xls"));
//creating workbook instance that refers to .xls file
HSSFWorkbook wb=new HSSFWorkbook(fis); 
//creating a Sheet object to retrieve the object
HSSFSheet sheet=wb.getSheetAt(0);
//evaluating cell type 
FormulaEvaluator formulaEvaluator=wb.getCreationHelper().createFormulaEvaluator();
for(Row row: sheet)     //iteration over row using for each loop
{
for(Cell cell: row)    //iteration over cell using for each loop
{
switch(formulaEvaluator.evaluateInCell(cell).getCellType())
{
case Cell.CELL_TYPE_NUMERIC:   //field that represents numeric cell type
//getting the value of the cell as a number
System.out.print(cell.getNumericCellValue()+ "\t\t"); 
break;
case Cell.CELL_TYPE_STRING:    //field that represents string cell type
//getting the value of the cell as a string
System.out.print(cell.getStringCellValue()+ "\t\t");
break;
}
}
System.out.println();
}
}
}

Output:

Name        Age        Height		
Swarit      23.0        5"
Puneet      25.0        6'1"
Swastik     22.0        5'5"
Tejas       12.0        4'9"

Reading XLSX File

All steps will remain same except file format.

Table: employee.xslx

Example of read excel file (.xlsx)

In this example we use XSSFWorkbook class.

import java.io.File;
import java.io.FileInputStream;
import java.util.Iterator;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class XLSXReaderExample
{
public static void main(String[] args) 
{
try
{
File file = new File("C:\\demo\\employee.xlsx");   //creating a new file instance
FileInputStream fis = new FileInputStream(file);   //obtaining bytes from the file
//creating Workbook instance that refers to .xlsx file
XSSFWorkbook wb = new XSSFWorkbook(fis); 
XSSFSheet sheet = wb.getSheetAt(0);     //creating a Sheet object to retrieve object
Iterator<Row> itr = sheet.iterator();    //iterating over excel file
while (itr.hasNext()) 				
{
Row row = itr.next();
Iterator<Cell> cellIterator = row.cellIterator();   //iterating over each column
while (cellIterator.hasNext()) 
{
Cell cell = cellIterator.next();
switch (cell.getCellType()) 			
{
case Cell.CELL_TYPE_STRING:    //field that represents string cell type
System.out.print(cell.getStringCellValue() + "\t\t\t");
break;
case Cell.CELL_TYPE_NUMERIC:    //field that represents number cell type
System.out.print(cell.getNumericCellValue() + "\t\t\t");
break;
default:
}
}
System.out.println("");
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

Output:

Employee ID   Employee Name    Salary     Designation          Department	
1223.0         Harsh           20000.0    Marketing Manager    Marketing
3213.0         Vivek           15000.0    Financial Advisor    Finance	
6542.0         Krishna         21000.0    HR Manager           HR		
9213.0         Sarika          34000.0    Sales Manager       Sales

Reading a particular cell value from a excel file (.xlsx)

Table: EmployeeData.xlsx

Example

In the following example, we read the value of the 2^nd row and the 2^nd column. The row and column counting start from 0. So the program returns "Software Engineer."

//reading value of a particular cell
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class ReadCellExample 
{
public static void main(String[] args) 
{
ReadCellExample rc=new ReadCellExample();	//object of the class
//reading the value of 2nd row and 2nd column
String vOutput=rc.ReadCellData(2, 2); 
System.out.println(vOutput);
}
//method defined for reading a cell
public String ReadCellData(int vRow, int vColumn)
{
String value=null;			//variable for storing the cell value
Workbook wb=null;			//initialize Workbook null
try
{
//reading data from a file in the form of bytes
FileInputStream fis=new FileInputStream("C:\\demo\\EmployeeData.xlsx");
//constructs an XSSFWorkbook object, by buffering the whole stream into the memory
wb=new XSSFWorkbook(fis);
}
catch(FileNotFoundException e)
{
e.printStackTrace();
}
catch(IOException e1)
{
e1.printStackTrace();
}
Sheet sheet=wb.getSheetAt(0);	//getting the XSSFSheet object at given index
Row row=sheet.getRow(vRow);	//returns the logical row
Cell cell=row.getCell(vColumn);	//getting the cell representing the given column
value=cell.getStringCellValue();	//getting cell value
return value;				//returns the cell value
}
}

Output: