What is most appropriate way to read all data from a text file in one go?

Question

I have a text file and I want to read the entire contents of it into a String variable. The file is being opened as an InputStream as I am using Android's assetManager.open() method.

What is the best practise way to read the entire contents into a String? I am currently wrapping the InputStream with an InputStreamReader and then a BufferedReader and using a while loop I read in the text line by line with the readLine() method.

Is there a better way of reading in this text considering I there is no requirement to read it in line by line, I'd like to get it all in one go if possible

Answer 1

This is what Java 7 Files.readAllLines method does - I would expect it to be a very good way of doing it (it uses a try-with-resources syntax which is easily transposable to work on android):

public static List<String> readAllLines(Path path, Charset cs) throws IOException {
    try (BufferedReader reader = newBufferedReader(path, cs)) {
        List<String> result = new ArrayList<String>();
        for (;;) {
            String line = reader.readLine();
            if (line == null)
                break;
            result.add(line);
        }
        return result;
    }
}

In your case, you could append the strings to a StringBuilder instead of adding them to a list.

Answer 2

One normally should not reinvent the wheel, so use the apache commons library, if the overhead is bearable on Android. Use org.apache.commons.io.IOUtils.toString.

InputStream in = new FileInputStream(new File("a.txt"));
String s = IOUtils.toString(in, "UTF-8");