如何将一个用utf-8编码的文本用java程序转换成ANSI编码的文本

 1 public static void main(String[] args) {
 2     StringBuffer buffer=new StringBuffer();
 3     try {
 4         FileInputStream fis=new FileInputStream("test.txt");
 5         InputStreamReader isr=new InputStreamReader(fis,"UTF-8");
 6         BufferedReader br=new BufferedReader(isr);
 7         String line=null;
 8         br.skip(1);
 9         while ((line=br.readLine())!=null) {
10             buffer.append(line);
11             buffer.append("\r\n");
12         }
13         buffer.delete(buffer.length()-2,buffer.length());
14         br.close();
15     } catch (Exception e) {
16         e.printStackTrace();
17     }
18     System.out.println(buffer);
19     try {
20         FileOutputStream fos=new FileOutputStream("test1.txt");
21         OutputStreamWriter osw=new OutputStreamWriter(fos);
22         osw.write(buffer.toString());
23         osw.flush();
24         osw.close();
25     } catch (Exception e) {
26         e.printStackTrace();
27     }
28 }