Streamtostring工具类

public class Streamtosring {    public static String tostring(InputStream s){        StringBuilder sb=new StringBuilder();        BufferedReader br=new BufferedReader(new InputStreamReader(s));        String con;        try {            while((con=br.readLine())!=null){                sb.append(con);            }            return sb.toString();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }}