Question

Does Java has a one line instruction to read to a text file, like what C# has?

I mean, is there something equivalent to this in Java?:

String data = System.IO.File.ReadAllText("path to file");

If not… what is the ‘optimal way’ to do this…?

Edit:

I prefer a way within Java standard libraries… I can not use 3rd party libraries..

Answer 1

Java 11 adds support for this use-case with Files.readString, sample code:

Files.readString(Path.of("/your/directory/path/file.txt"));

Before Java 11, typical approach with standard libraries would be something like this:

public static String readStream(InputStream is) {
    StringBuilder sb = new StringBuilder(512);
    try {
        Reader r = new InputStreamReader(is, "UTF-8");
        int c = 0;
        while ((c = r.read()) != -1) {
            sb.append((char) c);
        }
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
    return sb.toString();
}

Notes:

• in order to read text from file, use FileInputStream
• if performance is important and you are reading large files, it would be advisable to wrap the stream in BufferedInputStream
• the stream should be closed by the caller