How to load resource from jar file packaged in a war file? [duplicate]

Answer 1

You can access any resource on the standard classpath from a given instance

this.getClass().getResourceAsStream("name");

for example from your "myservlet" class (Bad naming).

getServletContext().getResourceAsStream() accesses content in the context of the web application base directory.

It seems bad style to incldue a WEB-INF directory in a jar - you would cause confusion. Can't you find a better name?

Answer 2

This is what I have found and it worked for me. The help provided by @BalusC worked for me. I have collated what I have found and how I have verified that it is working.

I have got a maven project with following structure as shown below

Now when I build this project; the jar looks like

and here queries.properties moves under "META-INF" folder. Now if this jar has a class which is trying to utilize this property file using Thread.currentThread().getContextClassLoader().getResourceAsStream("queries.properties")

thinking that the same file can still be accessed under resources folder as shown in project structure, that is wrong. The correct way is to access via META-INF folder

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream is = classLoader.getResourceAsStream("META-INF/queries.properties");

How did I verified

Just create a simple java project and include the jar you have just created into its build path and create an instance of class which is having ClassLoader statements as mentioned above. Your code in this new java project should look like

public static void main(String[] args){
        new Queries();
    }

where Queries is a class in jar you have just included in your build path.

Answer 3

Put it in root of the JAR and get it by context classloader instead of servletcontext.

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("test.properties");
// ...

The /WEB-INF folder convention is specific to WAR files, not to JAR files. Get rid of it. If you really need a separate JAR folder which is to be part of the classpath, use /META-INF instead.

ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("META-INF/test.properties");
// ...