How to Load a Classpath Resource into a Byte Array in Java?

How can I easily load a classpath resource into a byte array in Java?

byte[] data = ResourceUtils.getResourceAsBytes("/assets/myAsset.bin");

Loading classpath resources as byte arrays is a common requirement in Java applications. While you can manually read an InputStream into a byte array, there are convenient methods provided by popular libraries that streamline this process.

import org.springframework.core.io.Resource; 
import org.springframework.core.io.ResourceLoader; 
import java.io.IOException; 
import java.nio.file.Files;

public byte[] loadResourceAsBytes(String resourcePath) throws IOException { 
    Resource resource = resourceLoader.getResource(resourcePath); 
    return Files.readAllBytes(resource.getFile().toPath()); 
}

Causes

• Need to read binary files from the classpath.
• Inadequate handling of InputStream to byte array conversion.
• Desire for simpler, more maintainable code.

Solutions

• Use Spring's ResourceUtils to load resources as byte arrays.
• Utilize Apache Commons IO's IOUtils to convert InputStream to byte arrays.

Mistake: Forgetting to close the InputStream after reading.

Solution: Always use a try-with-resources statement or ensure the InputStream is closed in a finally block.

Mistake: Not handling IOException while reading the resource.

Solution: Implement appropriate exception handling to manage IOExceptions.