字节流转换为字符串的方法

private String streamToString(InputStream inputStream, String charset) {

    try {
        //转换流,将字节流转字符串,并转换编码
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream, charset);
        //字符缓冲流
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
        //字符串缓冲区
        StringBuilder stringBuilder = new StringBuilder();
        //
        String len = null;
        //按行读
        while((len=bufferedReader.readLine())!=null){
            //追加到字符串缓冲区存放
            stringBuilder.append(len);
        }
        //将字符串返回
        return stringBuilder.toString();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}