[Java] - Resource loader

ResourceReader.java

package com.example.util;

import java.io.File;
import java.io.InputStream;

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class ResourceReader {
	private static final Logger LOG = LoggerFactory.getLogger(ResourceReader.class);
	
	/** default file encoding */
	private static final String FILE_ENCODING = "UTF-8";
	
	private ResourceReader() {
	}
	
	/**
	 * Retrieve InputStream for the file located in resources
	 * @param filename - must be without leading slash
	 * @return InputStream
	 */
	public static InputStream getResourceAsStream(String filename) {
		LOG.debug("getResourceAsStream() START, filename={}", filename);
		
		InputStream inputStream = ResourceReader.class.getClassLoader().getResourceAsStream(filename);
		if (inputStream == null) {
			throw new RuntimeException("Can't find resource: " + filename);
		}
		LOG.debug("getResourceAsStream() END.");
		return inputStream;
	}

	/**
	 * Retrieve File for the file located in resources
	 * @param filename - must be without leading slash
	 * @return File
	 */
	public static File getResourceAsFile(String filename) {
		LOG.debug("getResourceAsFile() START, filename={}", filename);
		
		if (ResourceReader.class.getClassLoader().getResource(filename) == null) {
			throw new RuntimeException("Can't find resource: " + filename);
		}
		LOG.debug("getResourceAsFile() END, path={}", ResourceReader.class.getClassLoader().getResource(filename).getFile());
		return new File(ResourceReader.class.getClassLoader().getResource(filename).getFile());
	}
	
	/**
	 * Retrieve byte[] for the file located in resources
	 * @param filename - must be without leading slash
	 * @return File
	 */
	public static byte[] getResourceAsByteArray(String filename) {
		LOG.debug("getResourceAsByteArray() executing for filename={}", filename);
		try {
			return IOUtils.toByteArray(ResourceReader.getResourceAsStream(filename));
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	/**
	 * Retrieve String for the file located in resources
	 * @param filename - must be without leading slash
	 * @return File
	 */
	public static String getResourceAsString(String filename) {
		LOG.debug("getResourceAsString() executing for filename={}", filename);
		try {
			return IOUtils.toString((ResourceReader.getResourceAsStream(filename)), FILE_ENCODING );
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
	
}