Java で文字コード変換コマンドを作る

import java.io.*;

public class enctrans {
    public static void main(String a[])
        throws UnsupportedEncodingException, IOException {
        if(a.length != 3) {
            System.err.println("Usage: java enctrans file in_code out_code");
            System.exit(1);
        }

        InputStreamReader in = new InputStreamReader(
            new BufferedInputStream(new FileInputStream(a[0])),
            a[1]);
        OutputStreamWriter out = new OutputStreamWriter(
            new BufferedOutputStream(System.out),
            a[2]);

        int c;
        while(true) {
            if((c = in.read()) < 0) break;
            out.write(c);
        }
        in.close();
        out.flush();
        out.close();
    }
}