如何将Reader转换为InputStream,将Writer转换为OutputStream？

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;

public class ReaderWriterConverter {

    public static InputStream convertReaderToInputStream(Reader reader) {
        InputStream inputStream = new InputStream() {
            private final BufferedReader bufferedReader = new BufferedReader(reader);

            @Override
            public int read() throws IOException {
                return bufferedReader.read();
            }
        };
        return inputStream;
    }

    public static OutputStream convertWriterToOutputStream(Writer writer) {
        OutputStream outputStream = new OutputStream() {
            private final BufferedWriter bufferedWriter = new BufferedWriter(writer);

            @Override
            public void write(int b) throws IOException {
                bufferedWriter.write(b);
            }
        };
        return outputStream;
    }
}