由输入流读取文件内容
1:获取流

 //--由输入流中读取文件内容   static public String readeFromInputStream(InputStream in){        StringBuffer str = new StringBuffer();        try         {        InputStreamReader is = new InputStreamReader(in);        BufferedReader  br = new BufferedReader(is);        String fieldline = br.readLine();while (fieldline != null){str.append(fieldline+"\n");fieldline = br.readLine();}br.close();        is.close(); //关闭输入流        in.close();}catch (IOException e) {System.out.println("读取输入流失败！");}        return str.toString();    }