base64使用

public static void main(String args[]) throws Exception {
        InputStream in = null;
        byte[] data = null;
        in = new FileInputStream("C:\\Users\\HP\\Pictures\\unicom.jpg");
        data = new byte[in.available()];
        in.read(data);
        in.close();
        BASE64Encoder encoder = new BASE64Encoder();
        // 对字节数组Base64第一次编码
        String base64Encode1 = encoder.encode(data);
        // 对字节数组Base64再次编码
        String base64Encode2 = encoder.encode(base64Encode1.getBytes());
        System.out.println(base64Encode2);

        BASE64Decoder decoder = new BASE64Decoder();
        //base64第一次解码
        byte[] base64Decode1 = decoder.decodeBuffer(base64Encode2);
        //Base64再次解码
        byte[] base64Decode2 = decoder.decodeBuffer(new String(base64Decode1));
        //  System.out.println("解码完成");
        for(int i=0;i<base64Decode2.length;++i)
        {
            if(base64Decode2[i]<0)
            {//调整异常数据
                base64Decode2[i]+=256;
            }
        }
        //生成jpg图片
        OutputStream out = new FileOutputStream("C:\\Users\\HP\\Pictures\\unicom2.jpg");
        out.write(base64Decode2);
        out.flush();
        out.close();
    }