How to read properties file from web inf resource folder using classloader in java

Question

Any suggestions to read properties file kept inside WEB-INF/resource using class loader. Something like :-

String fileName = "/WEB-INF/resource/my.properties";
InputStream input =MyClass.class.getClassLoader().getResourceAsStream(fileName);
properties = new Properties(); 
properties.load(input);

(Note- I don't want to read using servletcontext)

Find the error for above code:-

java.lang.NullPointerException
at java.util.Properties$LineReader.readLine(Unknown Source)
at java.util.Properties.load0(Unknown Source)
at java.util.Properties.load(Unknown Source)

Answer 1

use ServletContext to access your web resources not the class loader

http://docs.oracle.com/javaee/6/api/javax/servlet/ServletContext.html#getResourceAsStream(java.lang.String)

servletContext.getResourceAsString("/WEB-INF/resource/my.properties");

Answer 2

When you're using getResourceAsStream() you're defaulting into the resources folder. Unless your WEB-INF is in the resources folder, it's won't find it because it doesn't exist.

If your source folder is src/main/com/mycompany/myapp/ and that's where web-inf is located, your path should be something like

String sourcePath = "../WEB-INF/resource/my.properties"

As you have to go back one folder (into the project root) and up into the WEB-INF folder.

Answer 3

I used this approach

public class HibernateConfig {

    public static final Properties HIBERNATE_PROPERTIES = readProperties();

    private static final String HIBERNATE_PROPERTIES_RESOURCE = "hibernate.properties";


    private static Properties readProperties() {
        try (BufferedInputStream is = new BufferedInputStream(ClassLoader.getSystemResourceAsStream(HIBERNATE_PROPERTIES_RESOURCE))) {
            Properties properties = new Properties();
            properties.load(is);
            return properties;
        } catch (IOException e) {
            throw new RuntimeException("Failed to read properties from scr/properties.");
        }
    }
}