UTF-8 byte[] to String

Question

Look at the constructor for String

String str = new String(bytes, StandardCharsets.UTF_8);

And if you're feeling lazy, you can use the Apache Commons IO library to convert the InputStream to a String directly:

String str = IOUtils.toString(inputStream, StandardCharsets.UTF_8);

Java String class has a built-in-constructor for converting byte array to string.

byte[] byteArray = new byte[] {87, 79, 87, 46, 46, 46};

String value = new String(byteArray, "UTF-8");

To convert utf-8 data, you can't assume a 1-1 correspondence between bytes and characters. Try this:

String file_string = new String(bytes, "UTF-8");

(Bah. I see I'm way to slow in hitting the Post Your Answer button.)

To read an entire file as a String, do something like this:

public String openFileToString(String fileName) throws IOException
{
    InputStream is = new BufferedInputStream(new FileInputStream(fileName));

    try {
        InputStreamReader rdr = new InputStreamReader(is, "UTF-8");
        StringBuilder contents = new StringBuilder();
        char[] buff = new char[4096];
        int len = rdr.read(buff);
        while (len >= 0) {
            contents.append(buff, 0, len);
        }
        return buff.toString();
    } finally {
        try {
            is.close();
        } catch (Exception e) {
            // log error in closing the file
        }
    }
}

You can use the String(byte[] bytes) constructor for that. See this link for details. EDIT You also have to consider your plateform's default charset as per the java doc:

Constructs a new String by decoding the specified array of bytes using the platform's default charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the byte array. The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.

You could use the methods described in this question (especially since you start off with an InputStream): Read/convert an InputStream to a String

In particular, if you don't want to rely on external libraries, you can try this answer, which reads the InputStream via an InputStreamReader into a char[] buffer and appends it into a StringBuilder.