Spring boot reading properties file returns null

Question

Hello I have the following project structure.

I want to store my properties file outside my jar , so that if I change any property it will be reflected automatically. My property file contains ip of the other servers, which might change, so that's why I want to keep my properties file outside my jar.

My resources folder contains all my properties file including application.propeties.

I am using following snippet to read from my properties file.

server_1 = new Properties();

server_1.load(PropertyReader.class.getClassLoader().getResourceAsStream("resources/server_1.properties"));

server_2 = new Properties();

server_2.load(PropertyReader.class.getClassLoader().getResourceAsStream("resources/server_2.properties"));

I have also tried

server_2.load(PropertyReader.class.getClassLoader().getResourceAsStream("server_2.properties"));


server_2.load(PropertyReader.class.getClassLoader().getResourceAsStream("/server_2.properties"));

But it gives me following error :

Caused by: java.lang.NullPointerException: null

I have gone through the this link so that's why I have created resources folder at src level still I am not able to understand this behaviour.

Thank you

You are confusing with the article which has absolute path. What your code does is checks for resources folder in the classpath. But your folder is outside your classpath. — Karthik R, May 07 '18 at 05:45
Could you please elaborate more and if the issue is with the class path how it could be resolved. — Salman Shaikh, May 07 '18 at 05:47
Added an answer as it contains bit of code. See if that helps. Note that the property path I have given is subject to your deployment structure and add the classpath entry according to your need. The classpath entry is relative to the jar's location. — Karthik R, May 07 '18 at 05:56
Just noticed that it's a spring boot project. I have updated answer. mention the resources folder as a property and referencing it in application is the neat approach. — Karthik R, May 07 '18 at 06:03

Karthik R · Answer 1 · 2018-05-07T06:02:43.337

To continue from my comment, If this a jar where you are separating resources outside the jar/bundle, you need the resources folder in the classpath of the jar.

For an executable jar in my project, I added a classpath entry(relative to the jar's location) in my jar's manifest entry via maven-jar plugin:

<plugin> 
   <artifactId>maven-jar-plugin</artifactId> 
     <configuration> 
       <archive> 
         <manifest> 
           <addClasspath>true</addClasspath> 
           <mainClass>....</mainClass> 
         </manifest> 
         <manifestEntries> 
           <Class-Path>../resources/</Class-Path> 
         </manifestEntries> 
       </archive> 
    </configuration> 
</plugin>

Check the MANIFEST.MF file for the added entry. Then you can use in your code directly(without resources folder) :

PropertyReader.class.getClassLoader().getResourceAsStream("server_1.properties");

For your unit tests, you can directly provide in src/resources.

UPDATE:

Just noticed that you mentioned it's a spring boot application. Refer to this one. Use profiles to mention location of resources folder. This way it's neater.

Spring Boot Reading Properties Files Based on classpath arg

Spring boot reading properties file returns null

1 Answers1