How to access text file in Maven Project using ClassPathResource in Java?

Question

I am trying to access file "raw_sentences.txt" file using "ClassPathResource" in Maven java project. My file is located in the "\\src\\main\\resources\\com\\thesis\\work\\raw_sentences.txt". I have tried many ways but it always returning with an error NullPointerExcepetion. I can access the file from

File testf = new File( obj.getClass().getResource( "raw_sentences.txt" ).toURI() );

But ClassPathResrouce is not working i don't know why, please help!

package com.thesis.work;

import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.core.io.ClassPathResource;

public class App 
{
static final Logger logger = Logger.getLogger("MyLog");  

public static void main( String[] args ) throws IOException, URISyntaxException
{   
    App obj = new App();
    File testf = new File( obj.getClass().getResource( "raw_sentences.txt" ).toURI() );
    logger.log(Level.INFO, "File: ", testf.getPath()); // Works!

    logger.log(Level.INFO, "Load data...\n");
    ClassPathResource resource = new ClassPathResource("raw_sentences.txt");
    logger.log(Level.INFO, "File loaded : ", resource.getPath()); // not Working!
}

static void print(String nd){
    System.out.println(nd);
}}

Exception in thread "main" java.io.FileNotFoundException: class path resource [raw_sentences.txt] cannot be opened because it does not exist at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:157) at com.thesis.work.App.main(App.java:24)

Answer 1

尝试ClassPathResource resource = new ClassPathResource("com/thesis/work/raw_sentences.txt");

Answer 2

They both shall be right.

Suppose there is the java file com/a/b/App.java , and the resource directory is com/a/b/test.test .

Then,

both

ClassPathResource resource = new ClassPathResource("/com/a/b/test.dat");

and

ClassPathResource resource = new ClassPathResource("test.dat");

should be fine.

The deep reason is that, maven would copy the contents of resource to target/classes/ .

Therefore, the test.dat is in the same directory with App.class , and test.dat or /com/a/b/test.dat both are right.

Here is the file structure in target :

  target
    |__
     classes
        └── a
            └── b
                |__
                   test.dat
                   App.class