java编码

java如何从gbk格式的文件中读取字符串保存为utf8的文件：

读入：        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(fileFrom), Charset.forName("GBK")));

写出：       BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileTo), Charset.forName("UTF-8")));