//写入操作 方法1

    OutputStream f = new FileOutputStream("C:/j/j.txt");

           f.write("aaaaaaa".getBytes());

           f.close();

        //写入操作 方法2

        File fi = new File("C:/j/j2.txt");

        OutputStream fo = new FileOutputStream(fi);

        fo.write("this is abc".getBytes());

        //读取数据方法1

        //InputStream f3 = new FileInputStream("C:/j/j2.txt");

        //读取数据方法2

        File f4 = new File("C:/j/j2.txt");

        InputStream  f3 = new FileInputStream(f4);

        int size = f3.available();

        for(int i=0; i< size; i++){

            System.out.print((char)f3.read() + "  ");

        }

        f3.close();