大家帮个忙,怎么解析这个base64编码

/**
* <p>Title: base64编码</p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2006</p>
*
* <p>Company: atdm</p>
*
* @author zhongxun
* @version 1.0
*/
public class BASE64Encoder {

        private static char[] codec_table = { 'A', 'B', 'C', 'D', 'E', 'F', 'G',
                'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
                'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
                'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
                'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6',
                '7', '8', '9', '+', '/' };

        public BASE64Encoder() {

        }

        public String encode(byte[] a) {
            int totalBits = a.length * 8;
            int nn = totalBits % 6;
            int curPos = 0;// process bits
            StringBuffer toReturn = new StringBuffer();
            while (curPos < totalBits) {
                int bytePos = curPos / 8;
                switch (curPos % {
                case 0:
                    toReturn.append(codec_table[(a[bytePos] & 0xfc) >> 2]);
                    break;
                case 2:

                    toReturn.append(codec_table[(a[bytePos] & 0x3f)]);
                    break;
                case 4:
                    if (bytePos == a.length - 1) {
                        toReturn
                                .append(codec_table[((a[bytePos] & 0x0f) << 2) & 0x3f]);
                    } else {
                        int pos = (((a[bytePos] & 0x0f) << 2) | ((a[bytePos + 1] & 0xc0) >>

6)) & 0x3f;
                        toReturn.append(codec_table[pos]);
                    }
                    break;
                case 6:
                    if (bytePos == a.length - 1) {
                        toReturn
                                .append(codec_table[((a[bytePos] & 0x03) << 4) & 0x3f]);
                    } else {
                        int pos = (((a[bytePos] & 0x03) << 4) | ((a[bytePos + 1] & 0xf0) >>

4)) & 0x3f;
                        toReturn.append(codec_table[pos]);
                    }
                    break;
                default:
                    //never hanppen
                    break;
                }
                curPos+=6;
            }
            if(nn==2)
            {
                toReturn.append("==");
            }
            else if(nn==4)
            {
                toReturn.append("=");
            }
            return toReturn.toString();

        }
}

我就是希望在服务器上能把图片文件通过这个方法解析发个服务器后在解析回来,data数组就可以了.服务端解析怎么写,谢谢大家了,希望打家帮个忙.
看不清的话下面有代码.  那个图像是个8的数字

大家帮个忙,怎么解析这个base64编码