How to really read text file from classpath in Java

Question

I am trying to read a text file which is set in CLASSPATH system variable. Not a user variable.

I am trying to get input stream to the file as below:

Place the directory of file (D:\myDir)in CLASSPATH and try below:

InputStream in = this.getClass().getClassLoader().getResourceAsStream("SomeTextFile.txt"); InputStream in = this.getClass().getClassLoader().getResourceAsStream("/SomeTextFile.txt"); InputStream in = this.getClass().getClassLoader().getResourceAsStream("//SomeTextFile.txt"); 

Place full path of file (D:\myDir\SomeTextFile.txt)in CLASSPATH and try the same above 3 lines of code.

But unfortunately NONE of them are working and I am always getting null into my InputStream in.

Answer 1

With the directory on the classpath, from a class loaded by the same classloader, you should be able to use either of:

// From ClassLoader, all paths are "absolute" already - there's no context // from which they could be relative. Therefore you don't need a leading slash. InputStream in = this.getClass().getClassLoader()                                 .getResourceAsStream("SomeTextFile.txt"); // From Class, the path is relative to the package of the class unless // you include a leading slash, so if you don't want to use the current // package, include a slash like this: InputStream in = this.getClass().getResourceAsStream("/SomeTextFile.txt"); 

If those aren't working, that suggests something else is wrong.

So for example, take this code:

package dummy;  import java.io.*;  public class Test {     public static void main(String[] args)     {         InputStream stream = Test.class.getResourceAsStream("/SomeTextFile.txt");         System.out.println(stream != null);         stream = Test.class.getClassLoader().getResourceAsStream("SomeTextFile.txt");         System.out.println(stream != null);     } } 

And this directory structure:

code     dummy           Test.class txt     SomeTextFile.txt 

And then (using the Unix path separator as I'm on a Linux box):

java -classpath code:txt dummy.Test 

Results:

true true