当我的班级和文本文件位于可执行JAR中时，如何编写代码访问文本文件？

Question

I know this question has been asked many, many times before, but the answers don't seem to help me. Here is my specific issue:

I have a class "TaQL" that accesses two text files from within its void main(String args[]) method. The two text files are in the same package as this class: package "taql". The following code runs fine within Eclipse (Mars) IDE:

    String stoplist = TaQL.class.getResource(stoplist).toURI().getPath();
    String input = TaQL.class.getResource(input).toURI().getPath();

When I output these two strings I get the correct path to the resource and the code hums along.

However, when I use this method after packaging everything up in a JAR, both strings return "null".

Here is what my code does with each of these text files in the non-JAR version

1. Get filename string for each text file.
2. create a new File object from one string and a new FileReader object from the other.
3. These are fed into a stoplist function and a data input iterator, respectively.

What I really need to be able to do is to seamlessly access these two text files once they are all in a JAR and then use some reference to these to create a File and FileReader object.

Here is some diagnostic code I put in my main method. It will show what the JAR file is seeing as far as files (note that both input and stoplist are filename strings):

    System.out.println("intput argument" + input);

    System.out.println("Resource path"+TaQL.class.getResource(stoplist));

    stoplist = TaQL.class.getResource(stoplist).toURI().getPath();
    input = TaQL.class.getResource(input).toURI().getPath();

    System.out.println("Path"+stoplist);
    System.out.println("Input path" + input);

command line output from running the JAR version of my program (note that this code works perfectly fine when I run from Eclipse)

Answer 1

To actually access the bytes of those files that may be in a jar file you need to use Class#getResourceAsStream(stopList). The URI will give you a path that cannot be used with File or FileInputStream. It's working in your IDE because the IDE has not yet packaged up the files, therefore the #getPath finds an actual file path.

So try this instead:

try (Reader inputReader = 
        new InputStreamReader(
            TaQL.class.getResourceAsStream(input))) {

    BufferedReader in = new BufferedReader(inputReader);

    for (String line; (line = in.readLine()) != null;) {
        // do something with the line
    }
}