Property File

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Update Specific Values in Java Properties File: Step-by-Step Guide

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What is a Properties File in Java?

In Java, a properties file is a simple text-based file used to store configuration or settings in key-value pairs. It provides a convenient way to externalize application-specific parameters that can be easily modified without modifying the source code.

Properties File always stores information about the configuration parameters such as project configuration data such as URL, username, password, and project settings config like browser name, environment, and so on.

Properties files have a “.properties” extension.

How to modify specific value in a Properties File without overwriting all the existing values

Imagine we want to update the value of a particular key in the existing properties file.

Below is an example of userCreated.properties.

We want to replace the password from Admin to Admin123.

Java API has java.util.Properties class, and it has utility stores() methods to store properties in Text format.

You can write properties to a properties file using the Properties class. Create a Properties object and use the load() method to load the existing properties from the file.

 Properties properties = new Properties();

 FileInputStream fileInputStream = new FileInputStream("src/test/resources/userCreated.properties");
 properties.load(fileInputStream);

Modify the specific value by using the “setProperty()” method to update the key-value pair in the “Properties” object.

properties.setProperty("password", "Admin123");

Save the changes back to the file. Create a “FileOutputStream” object and specify the same file path. Use the “store()” method to save the modified properties back to the file.

FileOutputStream fileOutputStream = new FileOutputStream("src/test/resources/userCreated.properties");

// store() method is used to write the properties into properties file
properties.store(fileOutputStream, "File is modified");

Below is a complete example:

package org.example;

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

public class ModifyPropertiesExample {

    public static void main(String args[]) {

        // Creating properties files from Java program
        Properties properties = new Properties();

        try {
            FileInputStream fileInputStream = new FileInputStream("src/test/resources/userCreated.properties");
            properties.load(fileInputStream);
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        properties.setProperty("password", "Admin123");
        try {
            FileOutputStream fileOutputStream = new FileOutputStream("src/test/resources/userCreated.properties");

            // store() method is used to write the properties into properties file
            properties.store(fileOutputStream, "File is modified");

            fileOutputStream.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

The updated userCreated.properties file is shown below:

Thank you for completing this tutorial! I’m glad you found it helpful. Happy learning and cheers to your success! 

vibssingh

Java Properties: Storing and Writing Data in XML Format

HOME

What is a Properties File in Java?

In Java, a properties file is a simple text-based file used to store configuration or settings in key-value pairs. It provides a convenient way to externalize application-specific parameters that can be easily modified without modifying the source code.

Properties File always stores information about the configuration parameters such as project configuration data such as URL, username, password, and project settings config like browser name, environment, and so on.

Properties files have a “.properties” extension.

How to write data in a Properties File in XML Format?

Java API got java.util.Properties class and it has several utility stores() methods to store properties in either Text or XML format. In order to store property in text format, Store() method can be used. storeToXML() is used to make  in XML format.

You can write properties to a properties file using the Properties class. Create a Properties object and set the key-value pairs

Properties properties = new Properties();
properties.setProperty("username", "Vibha");
properties.setProperty("password", "XML");

Specify the output file path and create an FileOutputStream object.

 FileOutputStream fileOutputStream = new FileOutputStream("src/test/resources/userCreatedXML.xml");

Write the properties to the output stream in XML format

properties.storeToXML(fileOutputStream, "Sample XML Properties file created");

Below is a complete example:

package org.example;

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

public class WritePropertiesXMLExample {

    public static void main(String args[]) {

        Properties properties = new Properties();
        properties.setProperty("username", "Vibha");
        properties.setProperty("password", "XML");

        try {
            // userCreated.properties is created at the mentioned path
            FileOutputStream fileOutputStream = new FileOutputStream("src/test/resources/userCreatedXML.xml");

            // storeToXML() method is used to write the properties into properties xml file
            properties.storeToXML(fileOutputStream, "Sample XML Properties file created");
            fileOutputStream.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

FileOutputStream: This class is used to create or overwrite the existing property file.

Pass this stream into the “storeToXML()” method of “Properties”, which writes the contents of the “Properties” object into the file in XML Format.

The output of the above execution is

userCreatedXML.xml file is created in src/test/resources.

The userCreatedXML.xml file is shown below:

Thank you for completing this tutorial! I’m glad you found it helpful. Happy learning and cheers to your success! 

vibssingh

How to Create and Modify Properties File in Java

HOME

What is a Properties File in Java?

In Java, a properties file is a simple text-based file used to store configuration or settings in key-value pairs. It provides a convenient way to externalize application-specific parameters that can be easily modified without modifying the source code.

Properties File always stores information about the configuration parameters such as project configuration data such as URL, username, password, and project settings config like browser name, environment, and so on.

Properties files have a “.properties” extension.

Why do we need a Properties File?

Properties files provide a convenient way to store configuration settings or parameters that can be easily modified without modifying the source code. It is not always a best practice to store the values as hardcoded in the project.

With properties files, you can have different versions of the file tailored for specific environments (e.g., development, testing, production). Each environment can have its own set of configurations while sharing a common structure and keys.

How to write data in a Properties File?

You can write properties to a properties file using the Properties class. Below is an example of how to do this:

package org.example;

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

public class WritePropertiesExample {

    public static void main(String args[]) {

        // Creating properties files from Java program
        Properties properties = new Properties();

        try {
            // userCreated.properties is created at the mentioned path
            FileOutputStream fileOutputStream = new FileOutputStream("src/test/resources/userCreated.properties");

            properties.setProperty("username", "Vibha");
            properties.setProperty("password", "Admin");

            // store() method is used to write the properties into properties file
            properties.store(fileOutputStream, "Sample way of creating Properties file from Java program");

            fileOutputStream.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

FileOutputStream: This class is used to create or overwrite the existing property file.

Pass this stream into the “store()” method of “Properties”, which writes the contents of the “Properties” object into the file.

The output of the above execution is

userCreated.properties file is created in src/test/resources.

The userCreated.properties file is shown below:

Thank you for completing this tutorial! I’m glad you found it helpful. Happy learning and cheers to your success! 

vibssingh

How to read property file in Java

HOME

What is a Properties File in Java?

In Java, a properties file is a simple text-based file used to store configuration or settings in key-value pairs. It provides a convenient way to externalize application-specific parameters that can be easily modified without modifying the source code.

Properties File is always storing information about the configuration parameters such as project configuration data such as URL, username, password, and project settings config like browser name, environment, and so on.

Properties files have a “.properties” extension.

Why do we need Properties File?

Properties files provide a convenient way to store configuration settings or parameters that can be easily modified without modifying the source code. It is not always a best practice to store the values as hard coded in the project.

With properties files, you can have different versions of the file tailored for specific environments (e.g., development, testing, production). Each environment can have its own set of configurations while sharing common structure and keys.

How to read data in a Properties File?

Steps to implement:

  1. Let us create a properties file (name it as config.properties)
  2. Add configuration data to the properties file.
  3. Create a java class to read the config file (name it as ConfigFileReader)

1.Create a Property File

Create a text file with the “.properties“ extension and define key-value pairs in it. For example, create a file named “config.properties”.

2. Add configuration data to the properties file.

We have added the configuration data to the property file in key-value pairs :

database.baseUrl = https://localhost
database.port = 8080
database.username = admin
database.password = Admin123

3. Create a java class to read the config file

You can load and read properties from this file using the Properties class. Below is an example of how to do this:

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class ReadPropertiesExample {

    public static void main(String[] args) {

        Properties properties = new Properties();
        try {
            InputStream inputStream = new FileInputStream("src/test/resources/config.properties");

            // Load the properties file
            properties.load(inputStream);

            // Access properties
            String dbUrl = properties.getProperty("database.baseUrl");
            String dbPort = properties.getProperty("database.port");
            String dbUser = properties.getProperty("database.username");
            String dbPassword = properties.getProperty("database.password");

            // Print properties to verify
            System.out.println("Database URL: " + dbUrl);
            System.out.println("Database Port: " + dbPort);
            System.out.println("Database User: " + dbUser);
            System.out.println("Database Password: " + dbPassword);

        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

FileInputStream: This class is used to read data from a file in the form of a sequence of bytes.load Method: The load method of the Properties class is used to read a properties file from an input stream.

The output of the above execution is

Congratulations on making it through this tutorial and hope you found it useful! Happy Learning!! Cheers!!