MD5加密JAVA实现代码

public class MD5 {
        static final int S11 = 7;
        static final int S12 = 12;
        static final int S13 = 17;
        static final int S14 = 22;

        static final int S21 = 5;
        static final int S22 = 9;
        static final int S23 = 14;
        static final int S24 = 20;

        static final int S31 = 4;
        static final int S32 = 11;
        static final int S33 = 16;
        static final int S34 = 23;

        static final int S41 = 6;
        static final int S42 = 10;
        static final int S43 = 15;
        static final int S44 = 21;

        static final byte[] PADDING = { -128,0 };

        private long[] state = new long[4];  // state (ABCD)
        private long[] count = new long[2];  // number of bits,modulo 2^64 (lsb first)
        private byte[] buffer = new byte[64]; // input buffer

        public String digestHexStr;

        private byte[] digest = new byte[16];

        public String getMD5ofStr(String inbuf) {
                md5Init();
                md5Update(inbuf.getBytes(),inbuf.length());
                md5Final();
                digestHexStr = "";
                for (int i = 0; i < 16; i++) {
                        digestHexStr += byteHEX(digest[i]);
                }
                return digestHexStr;

        }

        public MD5() {
                md5Init();

                return;
        }

        private void md5Init() {
                count[0] = 0L;
                count[1] = 0L;
                ///* Load magic initialization constants.

                state[0] = 0x67452301L;
                state[1] = 0xefcdab89L;
                state[2] = 0x98badcfeL;
                state[3] = 0x10325476L;

                return;
        }

        private long F(long x,long y,long z) {
                return (x & y) | ((~x) & z);

        }
        private long G(long x,long z) {
                return (x & z) | (y & (~z));

        }
        private long H(long x,long z) {
                return x ^ y ^ z;
        }

        private long I(long x,long z) {
                return y ^ (x | (~z));
        }

        private long FF(long a,long b,long c,long d,long x,long s,long ac) {
                a += F (b,c,d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }

        private long GG(long a,long ac) {
                a += G (b,d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }
        private long HH(long a,long ac) {
                a += H (b,d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }
        private long II(long a,long ac) {
                a += I (b,d) + x + ac;
                a = ((int) a << s) | ((int) a >>> (32 - s));
                a += b;
                return a;
        }
        private void md5Update(byte[] inbuf,int inputLen) {

                int i,index,partLen;
                byte[] block = new byte[64];
                index = (int)(count[0] >>> 3) & 0x3F;
                // /* Update number of bits */
                if ((count[0] += (inputLen << 3)) < (inputLen << 3))
                        count[1]++;
                count[1] += (inputLen >>> 29);

                partLen = 64 - index;

                // Transform as many times as possible.
                if (inputLen >= partLen) {
                        md5Memcpy(buffer,inbuf,partLen);
                        md5Transform(buffer);

                        for (i = partLen; i + 63 < inputLen; i += 64) {

                                md5Memcpy(block,i,64);
                                md5Transform (block);
                        }
                        index = 0;

                } else

                        i = 0;

                ///* Buffer remaining input */
                md5Memcpy(buffer,inputLen - i);

        }

        private void md5Final () {
                byte[] bits = new byte[8];
                int index,padLen;

                ///* Save number of bits */
                Encode (bits,count,8);

                ///* Pad out to 56 mod 64.
                index = (int)(count[0] >>> 3) & 0x3f;
                padLen = (index < 56) ? (56 - index) : (120 - index);
                md5Update (PADDING,padLen);

                ///* Append length (before padding) */
                md5Update(bits,8);

                ///* Store state in digest */
                Encode (digest,state,16);

        }

        private void md5Memcpy (byte[] output,byte[] input,int outpos,int inpos,int len)
        {
                int i;

                for (i = 0; i < len; i++)
                        output[outpos + i] = input[inpos + i];
        }

        private void md5Transform (byte block[]) {
                long a = state[0],b = state[1],c = state[2],d = state[3];
                long[] x = new long[16];

                Decode (x,block,64);

                /* Round 1 */
                a = FF (a,b,d,x[0],S11,0xd76aa478L); /* 1 */
                d = FF (d,a,x[1],S12,0xe8c7b756L); /* 2 */
                c = FF (c,x[2],S13,0x242070dbL); /* 3 */
                b = FF (b,x[3],S14,0xc1bdceeeL); /* 4 */
                a = FF (a,x[4],0xf57c0fafL); /* 5 */
                d = FF (d,x[5],0x4787c62aL); /* 6 */
                c = FF (c,x[6],0xa8304613L); /* 7 */
                b = FF (b,x[7],0xfd469501L); /* 8 */
                a = FF (a,x[8],0x698098d8L); /* 9 */
                d = FF (d,x[9],0x8b44f7afL); /* 10 */
                c = FF (c,x[10],0xffff5bb1L); /* 11 */
                b = FF (b,x[11],0x895cd7beL); /* 12 */
                a = FF (a,x[12],0x6b901122L); /* 13 */
                d = FF (d,x[13],0xfd987193L); /* 14 */
                c = FF (c,x[14],0xa679438eL); /* 15 */
                b = FF (b,x[15],0x49b40821L); /* 16 */

                /* Round 2 */
                a = GG (a,S21,0xf61e2562L); /* 17 */
                d = GG (d,S22,0xc040b340L); /* 18 */
                c = GG (c,S23,0x265e5a51L); /* 19 */
                b = GG (b,S24,0xe9b6c7aaL); /* 20 */
                a = GG (a,0xd62f105dL); /* 21 */
                d = GG (d,0x2441453L); /* 22 */
                c = GG (c,0xd8a1e681L); /* 23 */
                b = GG (b,0xe7d3fbc8L); /* 24 */
                a = GG (a,0x21e1cde6L); /* 25 */
                d = GG (d,0xc33707d6L); /* 26 */
                c = GG (c,0xf4d50d87L); /* 27 */
                b = GG (b,0x455a14edL); /* 28 */
                a = GG (a,0xa9e3e905L); /* 29 */
                d = GG (d,0xfcefa3f8L); /* 30 */
                c = GG (c,0x676f02d9L); /* 31 */
                b = GG (b,0x8d2a4c8aL); /* 32 */

                /* Round 3 */
                a = HH (a,S31,0xfffa3942L); /* 33 */
                d = HH (d,S32,0x8771f681L); /* 34 */
                c = HH (c,S33,0x6d9d6122L); /* 35 */
                b = HH (b,S34,0xfde5380cL); /* 36 */
                a = HH (a,0xa4beea44L); /* 37 */
                d = HH (d,0x4bdecfa9L); /* 38 */
                c = HH (c,0xf6bb4b60L); /* 39 */
                b = HH (b,0xbebfbc70L); /* 40 */
                a = HH (a,0x289b7ec6L); /* 41 */
                d = HH (d,0xeaa127faL); /* 42 */
                c = HH (c,0xd4ef3085L); /* 43 */
                b = HH (b,0x4881d05L); /* 44 */
                a = HH (a,0xd9d4d039L); /* 45 */
                d = HH (d,0xe6db99e5L); /* 46 */
                c = HH (c,0x1fa27cf8L); /* 47 */
                b = HH (b,0xc4ac5665L); /* 48 */

                /* Round 4 */
                a = II (a,S41,0xf4292244L); /* 49 */
                d = II (d,S42,0x432aff97L); /* 50 */
                c = II (c,S43,0xab9423a7L); /* 51 */
                b = II (b,S44,0xfc93a039L); /* 52 */
                a = II (a,0x655b59c3L); /* 53 */
                d = II (d,0x8f0ccc92L); /* 54 */
                c = II (c,0xffeff47dL); /* 55 */
                b = II (b,0x85845dd1L); /* 56 */
                a = II (a,0x6fa87e4fL); /* 57 */
                d = II (d,0xfe2ce6e0L); /* 58 */
                c = II (c,0xa3014314L); /* 59 */
                b = II (b,0x4e0811a1L); /* 60 */
                a = II (a,0xf7537e82L); /* 61 */
                d = II (d,0xbd3af235L); /* 62 */
                c = II (c,0x2ad7d2bbL); /* 63 */
                b = II (b,0xeb86d391L); /* 64 */

                state[0] += a;
                state[1] += b;
                state[2] += c;
                state[3] += d;

        }

        private void Encode (byte[] output,long[] input,int len) {
                int i,j;

                for (i = 0,j = 0; j < len; i++,j += 4) {
                        output[j] = (byte)(input[i] & 0xffL);
                        output[j + 1] = (byte)((input[i] >>> 8) & 0xffL);
                        output[j + 2] = (byte)((input[i] >>> 16) & 0xffL);
                        output[j + 3] = (byte)((input[i] >>> 24) & 0xffL);
                }
        }

        private void Decode (long[] output,j += 4)
                        output[i] = b2iu(input[j]) |
                                (b2iu(input[j + 1]) << 8) |
                                (b2iu(input[j + 2]) << 16) |
                                (b2iu(input[j + 3]) << 24);

                return;
        }

        public static long b2iu(byte b) {
                return b < 0 ? b & 0x7F + 128 : b;
        }

        public static String byteHEX(byte ib) {
                char[] Digit = { '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F' };
                char [] ob = new char[2];
                ob[0] = Digit[(ib >>> 4) & 0X0F];
                ob[1] = Digit[ib & 0X0F];
                String s = new String(ob);
                return s;
        }

        public static void main(String args[]) {

                MD5 m = new MD5();

                String tmp =  m.getMD5ofStr("1");
                System.out.println(tmp);

        }

}