Utils to read resource text file to String (Java) [closed]

Answer 1

For java 7:

new String(Files.readAllBytes(Paths.get(getClass().getResource("foo.txt").toURI())));

Answer 2

Pure and simple, jar-friendly, Java 8+ solution

This simple method below will do just fine if you're using Java 8 or greater:

/**
 * Reads given resource file as a string.
 *
 * @param fileName path to the resource file
 * @return the file's contents
 * @throws IOException if read fails for any reason
 */
static String getResourceFileAsString(String fileName) throws IOException {
    ClassLoader classLoader = ClassLoader.getSystemClassLoader();
    try (InputStream is = classLoader.getResourceAsStream(fileName)) {
        if (is == null) return null;
        try (InputStreamReader isr = new InputStreamReader(is);
             BufferedReader reader = new BufferedReader(isr)) {
            return reader.lines().collect(Collectors.joining(System.lineSeparator()));
        }
    }
}

And it also works with resources in jar files.

About text encoding: InputStreamReader will use the default system charset in case you don't specify one. You may want to specify it yourself to avoid decoding problems, like this:

new InputStreamReader(isr, StandardCharsets.UTF_8);

---

Avoid unnecessary dependencies

Always prefer not depending on big, fat libraries. Unless you are already using Guava or Apache Commons IO for other tasks, adding those libraries to your project just to be able to read from a file seems a bit too much.

"Simple" method? You must be kidding me

I understand that pure Java does not do a good job when it comes to doing simple tasks like this. For instance, this is how we read from a file in Node.js:

const fs = require("fs");
const contents = fs.readFileSync("some-file.txt", "utf-8");

Simple and easy to read (although people still like to rely on many dependencies anyway, mostly due to ignorance). Or in Python:

with open('some-file.txt', 'r') as f:
    content = f.read()

It's sad, but it's still simple for Java's standards and all you have to do is copy the method above to your project and use it. I don't even ask you to understand what is going on in there, because it really doesn't matter to anyone. It just works, period :-)

Answer 3

public static byte[] readResoureStream(String resourcePath) throws IOException {
    ByteArrayOutputStream byteArray = new ByteArrayOutputStream();
    InputStream in = CreateBffFile.class.getResourceAsStream(resourcePath);

    //Create buffer
    byte[] buffer = new byte[4096];
    for (;;) {
        int nread = in.read(buffer);
        if (nread <= 0) {
            break;
        }
        byteArray.write(buffer, 0, nread);
    }
    return byteArray.toByteArray();
}

Charset charset = StandardCharsets.UTF_8;
String content = new   String(FileReader.readResoureStream("/resource/...*.txt"), charset);
String lines[] = content.split("\\n");

Answer 4

I'm using the following for reading resource files from the classpath:

import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.util.Scanner;

public class ResourceUtilities
{
    public static String resourceToString(String filePath) throws IOException, URISyntaxException
    {
        try (InputStream inputStream = ResourceUtilities.class.getClassLoader().getResourceAsStream(filePath))
        {
            return inputStreamToString(inputStream);
        }
    }

    private static String inputStreamToString(InputStream inputStream)
    {
        try (Scanner scanner = new Scanner(inputStream).useDelimiter("\\A"))
        {
            return scanner.hasNext() ? scanner.next() : "";
        }
    }
}

No third party dependencies required.

Answer 5

package test;

import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try {
            String fileContent = getFileFromResources("resourcesFile.txt");
            System.out.println(fileContent);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //USE THIS FUNCTION TO READ CONTENT OF A FILE, IT MUST EXIST IN "RESOURCES" FOLDER
    public static String getFileFromResources(String fileName) throws Exception {
        ClassLoader classLoader = Main.class.getClassLoader();
        InputStream stream = classLoader.getResourceAsStream(fileName);
        String text = null;
        try (Scanner scanner = new Scanner(stream, StandardCharsets.UTF_8.name())) {
            text = scanner.useDelimiter("\\A").next();
        }
        return text;
    }
}

Answer 6

I've written readResource() methods here, to be able to do it in one simple invocation. It depends on the Guava library, but I like JDK-only methods suggested in other answers and I think I'll change these that way.