把一个字节流转换为字符串的方法

/**
 *  把一个字节流转换为字符串的方法
 *  @param inputStream
 *  @param charset
 *  @return
 *      
 */
private String streamToString(InputStream inputStream, String charset) {
    try {
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream, charset);
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
        String s = null;
        StringBuilder builder = new StringBuilder();
        while ((s = bufferedReader.readLine()) != null) {
            builder.append(s);
        }
        bufferedReader.close();
        return builder.toString();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return  null;
}