Cannot read file within jar file

Question

I developped an application using spring-boot, I need to read a csv file that contain emails.

this is a snippet how I do:

public Set readFile         


        

Answer 1

The javadocs for ClassPathResource state:

Supports resolution as java.io.File if the class path resource resides in the file system, but not for resources in a JAR. Always supports resolution as URL.

So when the resource (the CSV file) is in a JAR file, getFile() is going to fail.

The solution is to use getURL() instead, then open the URL as an input stream, etcetera. Something like this:

public Set readFile() {
    Set setOfEmails = new HashSet();

    ClassPathResource cl = new ClassPathResource("myFile.csv");
    URL url = cl.getURL();
    try (BufferedReader br = new BufferedReader(
                             new InputStreamReader(url.openStream()))) {

        Stream stream = br.lines();
        setOfEmails = stream.collect(Collectors.toSet());
    } catch (IOException e) {
        logger.error("file error " + e.getMessage());
    }
    return setOfEmails;
} 

If it still fails check that you are using the correct resource path.