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How to read Properties file and writing it to Excel file in Java using Apache Poi API ?.


Program to demonstrate how to read Properties file and writing it to Excel file in Java using Apache Poi API.

Note :- Please include poi-3.2-FINAL.jar into the classpath of your ide before running the below program.

package com.hubberspot.code;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Properties;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
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.hssf.util.HSSFColor;

public class ReadWriteXlsProperties {

	// Create a HashMap which will store the properties  
	HashMap< String, String > propMap = new HashMap< String, String >();


	public static void main(String[] args) {

		// Create object of ReadWriteXlsProperties
		ReadWriteXlsProperties readWriteXlsDemo = new ReadWriteXlsProperties();

		// Call method readProperties() it take path to properties file 
		readWriteXlsDemo.readProperties("config.properties");

		// Call method writeToExcel() it will take path to excel file
		readWriteXlsDemo.writeToExcel("test.xls");

	}


	private void readProperties(String propertiesFilePath) {

		// Create a File object taking in path of properties 
		// file
		File propertiesFile = new File(propertiesFilePath);

		// If properties file is a file do below stuff
		if(propertiesFile.isFile())
		{
			try
			{
				// Create a FileInputStream for loading the properties file
				FileInputStream fisProp = new FileInputStream(propertiesFile);

				// Create a Properties object and load 
				// properties key and value to it through FileInputStream
				Properties properties = new Properties();                  
				properties.load(fisProp);

				// Create a object of Enumeration and call keys()
				// method over properties object created above
				// it will return us back with a Enumeration types
				Enumeration< Object > keysEnum = properties.keys();

				// Looping over the elements of Enumeration
				while(keysEnum.hasMoreElements())
				{
					// Extracting the key and respective values from it.
					String propKey = (String)keysEnum.nextElement();
					String propValue = (String)properties.getProperty(propKey);

					// After extracting the key and value from the properties file
					// we will store the values in a HashMap.
					propMap.put( propKey.toLowerCase().trim(),propValue.toLowerCase().trim());

				}    

				// printing the HashMap and closing the file FileInputStream
				System.out.println("Properties Map ... \n" +  propMap);
				fisProp.close();

			}
			catch(FileNotFoundException e)
			{                      
				e.printStackTrace();
			}
			catch(IOException e)
			{                   
				e.printStackTrace();
			}

		}

	}

	private void writeToExcel(String excelPath) {

		// Create a Workbook using HSSFWorkbook object
		HSSFWorkbook workBook = new HSSFWorkbook();

		// Create a sheet with name "properties" by 
		// the createSheet method of the Workbook
		HSSFSheet worksheet = workBook.createSheet("Properties");

		// Create a row by calling createRow method of the 
		// Worksheet
		HSSFRow row = worksheet.createRow((short) 0);

		// Create a cell style by calling createCellStyle()
		// from the workbook
		HSSFCellStyle cellStyle = workBook.createCellStyle();

		// setting of the foreground and fill pattern by calling methods
		// of HSSFCellStyle as setFillForegroundColor() and setFillPattern()

		cellStyle.setFillForegroundColor(HSSFColor.GOLD.index);
		cellStyle.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);

		// Create a HSSFCell from the row object created above 
		HSSFCell cell1 = row.createCell(0);

		// Setting the value of the cell as the keys by calling 
		// setCellValue() method over the HSSFCell
		cell1.setCellValue(new HSSFRichTextString("Keys"));

		// Giving it the style created above.
		cell1.setCellStyle(cellStyle);

		HSSFCell cell2 = row.createCell(1);
		cell2.setCellValue(new HSSFRichTextString("Values"));                 
		cell2.setCellStyle(cellStyle);

		// Create a Iterator and as  propMap is a HashMap 
		// it is converted to a HashSet by calling keySet() method 
		// which will return with Set.
		// Iterator object is pointed to keys of Set
		Iterator< String > iterator = propMap.keySet().iterator();

		// Looping across the elements of Iterator
		while(iterator.hasNext())
		{          
			// Creating a new row from the worksheet
			// at the last used row + 1 location
			HSSFRow rowOne = worksheet.createRow(worksheet.getLastRowNum()+1);

			// Creating two cells in the row at 0 and 1 position.
			HSSFCell cellZero = rowOne.createCell(0);
			HSSFCell cellOne = rowOne.createCell(1);

			// extracting key and value from the map and set
			String key = (String) iterator.next();
			String value = (String) propMap.get(key);

			// setting the extracted keys and values in the cells 
			cellZero.setCellValue(new HSSFRichTextString(key));
			cellOne.setCellValue(new HSSFRichTextString(value));

		}          

		try{

			FileOutputStream fosExcel =null;         

			// Creating a xls File
			File fileExcel = new File(excelPath);                

			// Setting the File to FileOutputStream
			fosExcel = new FileOutputStream(fileExcel);

			// Writing the contents of workbook to the xls
			workBook.write(fosExcel);

			// Flushing the FileOutputStream
			fosExcel.flush();
			// Closing the FileOutputStream
			fosExcel.close();

		}catch(Exception e){

			e.printStackTrace();

		}
	}
}



 
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