读取帮助类（StreamTools）

public class StreamTools {
    public static String readStreamTools(InputStream is){
        try {
            ByteArrayOutputStream baos=new ByteArrayOutputStream();
            byte[] buffer=new byte[1024];
            int len=0;
            while ((len=is.read(buffer))!=-1){
                baos.write(buffer,0,len);
            }
            return baos.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}