OutputStreamWriter osw, osw.append(buffer); 这样用对吗？

Question

                File fa=new File("E:/a.txt");

FileInputStream fais=new FileInputStream(fa);

InputStreamReader isr=new InputStreamReader(fais,"UTF-8");

StringBuffer sbf=new StringBuffer();

while(isr.ready()){

sbf.append((char)isr.read());

}

isr.close();

fais.close();

File fb=new File("E:/b.txt");

FileOutputStream fbos=new FileOutputStream(fb);

OutputStreamWriter osw=new OutputStreamWriter(fbos,"UTF-8");

osw.append(sbf); //buffer直接带入，能这样写吗？

osw.close();

fbos.close();