字节流转换字符流

public static 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;
    }