Properties file reading and writing example with Java

java_properties_example.java

package com.morenoamor.tutorials;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

/**
 * Properties file reading and writing example
 * 
 * @author Jesús Moreno Amor <[email protected]>
 */
public class PropertiesFile
{
  public static void main(String[] args)
  {
    String properties_file_path = "/path/to/file/properties_file.properties";

    FileInputStream input_stream = null;
    FileOutputStream output_stream = null;

    try
    {
      Properties properties = new Properties();

      // Loading from INI format
      input_stream = new FileInputStream(properties_file_path);
      properties.load(input_stream);
      input_stream.close();

      // Loading from XML fromat
      input_stream = new FileInputStream(properties_file_path);
      properties.loadFromXML(input_stream);
      input_stream.close();
      
      // Gettng value of a property
      System.out.println("The value of key_name key is: " + properties.getProperty("key_name"));

      // Setting value of a property
      properties.setProperty("keyA", "value1");
      properties.setProperty("keyB", "value2");
      properties.setProperty("keyC", "value3");

      // Storing to INI format
      output_stream = new FileOutputStream(properties_file_path);
      properties.store(output_stream, "Comments");
      output_stream.close();

      // Storing to XML format
      output_stream = new FileOutputStream(properties_file_path);
      properties.storeToXML(output_stream, "Comments");
      output_stream.close();
      
    } catch (FileNotFoundException ex) {
      ex.printStackTrace();
    } catch (IOException ex) {
      ex.printStackTrace();
    }
  }
}