How to read/write data from/to .properties file in Java?

The .properties is an extension in java which is used to store configurable application. It is represented by the Properties class in Java, you can store a properties file and read from it using the methods of this class. This class inherits the HashTable class.

Creating a .properties file −

To create a properties file −

• Instantiate the Properties class.

• Populate the created Properties object using the put() method.

• Instantiate the FileOutputStream class by passing the path to store the file, as a parameter.

Example

The Following Java program creates a properties file in the path D:/ExampleDirectory/

 Live Demo

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
public class CreatingPropertiesFile {
   public static void main(String args[]) throws IOException {
      //Instantiating the properties file
      Properties props = new Properties();
      //Populating the properties file
      props.put("Device_name", "OnePlus7");
      props.put("Android_version", "9");
      props.put("Model", "GM1901");
      props.put("CPU", "Snapdragon855");
      //Instantiating the FileInputStream for output file
      String path = "D:\ExampleDirectory\myFile.properties";
      FileOutputStream outputStrem = new FileOutputStream(path);
      //Storing the properties file
      props.store(outputStrem, "This is a sample properties file");
      System.out.println("Properties file created......");
   }
}

Output

Properties file created......

If you observe the output file you can see the created contents as −

Storing properties file in XML format

You can store the properties file in XML format using the stored XML() method.

Example

 Live Demo

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
public class CreatingPropertiesFile {
   public static void main(String args[]) throws IOException {
      //Instantiating the properties file
      Properties props = new Properties();
      //Populating the properties file
      props.put("Device_name", "OnePlus7");
      props.put("Android_version", "9");
      props.put("Model", "GM1901");
      props.put("CPU", "Snapdragon855");
      //Instantiating the FileInputStream for output file
      String outputPath = "D:\ExampleDirectory\myFile.xml";
      FileOutputStream outputStrem = new FileOutputStream(outputPath);
      //Storing the properties file in XML format
      props.storeToXML(outputStrem, "This is a sample properties file");
      System.out.println("Properties file created......");
   }
}

Output

Properties file created......