Here's an example of how to use the StreamIterator class from the Apache Commons IO library:

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.StreamIterator;

public class Example {
    public static void main(String[] args) {
        File file = new File("example.txt");
        try {
            StreamIterator it = new StreamIterator(FileUtils.openInputStream(file));
            try {
                while (it.hasNext()) {
                    InputStream stream = it.next();
                    String content = IOUtils.toString(stream, "UTF-8");
                    System.out.println(content);
                }
            } finally {
                it.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, a StreamIterator object is created to read the contents of a file named "example.txt" using the FileUtils.openInputStream(file). The hasNext() method is used to check if there are more stream to read and the next() method is used to read the next stream. The file content is then printed to the console using IOUtils.toString(stream, "UTF-8"). Finally, the close() method is used to close the iterator, suppressing any exceptions that might be thrown.

Note: The StreamIterator class provides an easy way to read a file as a stream of bytes. This class provides a convenient and efficient way of reading a large file as a stream of bytes, without having to load the entire file into memory at once.