IOUtils.java

import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;

/**
 * @author Aleks Sander
 */
@SuppressWarnings("WeakerAccess")
public final class IOUtils {

    private static final String UTF_8 = "UTF-8";
    private static final int BUFFER_SIZE = 4096;

    private IOUtils() {
        //empty
    }

    @Nullable
    public static String getStringFrom(@Nullable InputStream inputStream) throws IOException {
        String result = null;
        try {
            if (inputStream != null) {
                result = writeStreamToString(inputStream);
            }
        } finally {
            closeQuietly(inputStream);
        }
        return result;
    }

    public static String writeStreamToString(@NonNull InputStream inputStream) throws IOException {
        String result;
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        try {
            result = readStreamAndConvert(inputStream, outputStream);
        } finally {
            closeQuietly(outputStream);
        }
        return result;
    }

    private static String readStreamAndConvert(@NonNull InputStream inputStream, @NonNull ByteArrayOutputStream outputStream) throws IOException {
        String result;
        byte[] buffer = new byte[BUFFER_SIZE];
        int length;
        while ((length = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, length);
        }
        result = outputStream.toString(UTF_8);
        return result;
    }

    public static void closeQuietly(Closeable stream) {
        try {
            if (stream != null) {
                stream.close();
            }
        } catch (Exception ex) {
            Log.E(ex);
        }
    }
}