My Wiki: How to read a properties file in a web application

How to read a properties file in a web application

The code to do this is pretty simple. But going by the number of people who keep asking this question, i thought i would post the code over here. Let's consider that you have a war file named SampleApp.war which has a properties file named myApp.properties at it's root :

SampleApp.war
|
|-------- myApp.properties
|
|-------- WEB-INF
|
|---- classes
|
|----- org
|------ myApp
|------- MyPropertiesReader.class

Let's assume that you want to read the property named "abc" present in the properties file:

----------------
myApp.properties:
----------------

abc=some value
xyz=some other value

Let's consider that the class org.myApp.MyPropertiesReader present in your application wants to read the property. Here's the code for the same:

view plaincopy to clipboardprint?package org.myapp; import java.io.IOException; import java.io.InputStream; import java.util.Properties; /** * Simple class meant to read a properties file * * @author Jaikiran Pai * */ public class MyPropertiesReader { /** * Default Constructor * */ public MyPropertiesReader() { } /** * Some Method * * @throws IOException * */ public void doSomeOperation() throws IOException { // Get the inputStream InputStream inputStream = this.getClass().getClassLoader() .getResourceAsStream("myApp.properties"); Properties properties = new Properties(); System.out.println("InputStream is: " + inputStream); // load the inputStream using the Properties properties.load(inputStream); // get the value of the property String propValue = properties.getProperty("abc"); System.out.println("Property value is: " + propValue); } }

package org.myapp;

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

/**
* Simple class meant to read a properties file
*
* @author Jaikiran Pai
*
*/
public class MyPropertiesReader {

/**
* Default Constructor
*
*/
public MyPropertiesReader() {

}

/**
* Some Method
*
* @throws IOException
*
*/
public void doSomeOperation() throws IOException {
// Get the inputStream
InputStream inputStream = this.getClass().getClassLoader()
.getResourceAsStream("myApp.properties");

Properties properties = new Properties();

System.out.println("InputStream is: " + inputStream);

// load the inputStream using the Properties
properties.load(inputStream);
// get the value of the property
String propValue = properties.getProperty("abc");

System.out.println("Property value is: " + propValue);
}

}

Pretty straight-forward. Now suppose the properties file is not at the root of the application, but inside a folder (let's name it config) in the web application, something like:

SampleApp.war
|
|-------- config
|           |------- myApp.properties
|
|
|-------- WEB-INF
|
|---- classes
|
|----- org
|------ myApp
|------- MyPropertiesReader.class

There will just be one line change in the above code:

view plaincopy to clipboardprint?public void doSomeOperation() throws IOException {
//Get the inputStream-->This time we have specified the folder name too.
InputStream inputStream = this.getClass().getClassLoader()
.getResourceAsStream("config/myApp.properties");

Properties properties = new Properties();

System.out.println("InputStream is: " + inputStream);

//load the inputStream using the Properties
properties.load(inputStream);
//get the value of the property
String propValue = properties.getProperty("abc");

System.out.println("Property value is: " + propValue);
}

public void doSomeOperation() throws IOException {
//Get the inputStream-->This time we have specified the folder name too.
InputStream inputStream = this.getClass().getClassLoader()
.getResourceAsStream("config/myApp.properties");

Properties properties = new Properties();

System.out.println("InputStream is: " + inputStream);

//load the inputStream using the Properties
properties.load(inputStream);
//get the value of the property
String propValue = properties.getProperty("abc");

System.out.println("Property value is: " + propValue);
}

That's all that is required to get it working.