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

Is there any utility that helps to read a text file in the resource into a String. I suppose this is a popular requirement, but I couldn't find any utility after Googling.

Solution 1:

Yes, Guava provides this in the Resources class. For example:

URL url = Resources.getResource("foo.txt");
String text = Resources.toString(url, StandardCharsets.UTF_8);

Solution 2:

You can use the old Stupid Scanner trick oneliner to do that without any additional dependency like guava:

String text = new Scanner(AppropriateClass.class.getResourceAsStream("foo.txt"), "UTF-8").useDelimiter("\\A").next();

Guys, don't use 3rd party stuff unless you really need that. There is a lot of functionality in the JDK already.

Solution 3:

For java 7:

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

Solution 4:

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 :-)

Solution 5:

Guava has a "toString" method for reading a file into a String:

import com.google.common.base.Charsets;
import com.google.common.io.Files;

String content = Files.toString(new File("/home/x1/text.log"), Charsets.UTF_8);

This method does not require the file to be in the classpath (as in Jon Skeet previous answer).