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();
     }