java生成16位的MD5值

   这是java实现16位的MD5值的代码。很基础的东西。保存一下。

package com.thinkive.util;



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, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
      0, 0, 0, 0
  };
  private long state[];
  private long count[];
  private byte buffer[];
  private byte digest[];
  
  private static final MD5 instance=new MD5();

  /**
   * Constructs a new MD5 instance.
   */
  private MD5() {
      state = new long[4];
      count = new long[2];
      buffer = new byte[64];
      digest = new byte[16];
  }
  
  public static MD5 getInstance() {
    return instance;
  }

  /**
   * Returns a new String of MD5 for input String.<br>
   * Encrypts one password to 16bits MD5 password.<br>
   * If you want 32 bits MD5 password, change the code from "for(int i = 0; i<8; i++)" to "for(int i = 0; i < 16; i++)", and recompile this file, and change the length of password's column of table author.
   * @param str input String for translate.
   * @return the new String has been translated to MD5 of input string.
   */
  public synchronized String getMD5(String str) {
      md5Init();
      md5Update(str.getBytes(), str.length());
      md5Final();
      StringBuffer sb=new StringBuffer();
      for(int i = 0; i < 8; i++) {
    	  // 8-->16
        sb.append(byteHEX(digest[i]));
      }
      return sb.toString();
  }

  private void md5Init() {
      count[0] = 0L;
      count[1] = 0L;
      state[0] = 0x67452301L;
      state[1] = 0xefcdab89L;
      state[2] = 0x98badcfeL;
      state[3] = 0x10325476L;
  }

  private long F(long l, long l1, long l2) {
      return l & l1 | ~l & l2;
  }

  private long G(long l, long l1, long l2) {
      return l & l2 | l1 & ~l2;
  }

  private long H(long l, long l1, long l2) {
      return l ^ l1 ^ l2;
  }

  private long I(long l, long l1, long l2) {
      return l1 ^ (l | ~l2);
  }

  private long FF(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
      l += F(l1, l2, l3) + l4 + l6;
      l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
      l += l1;
      return l;
  }

  private long GG(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
      l += G(l1, l2, l3) + l4 + l6;
      l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
      l += l1;
      return l;
  }

  private long HH(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
      l += H(l1, l2, l3) + l4 + l6;
      l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
      l += l1;
      return l;
  }

  private long II(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
      l += I(l1, l2, l3) + l4 + l6;
      l = (int)l << (int)l5 | (int)l >>> (int)(32L - l5);
      l += l1;
      return l;
  }

  private void md5Update(byte abyte0[], int i) {
      byte abyte1[] = new byte[64];
      int k = (int)(count[0] >>> 3) & 0x3f;
      if((count[0] += i << 3) < (long)(i << 3))
          count[1]++;
      count[1] += i >>> 29;
      int l = 64 - k;
      int j;
      if(i >= l) {
          md5Memcpy(buffer, abyte0, k, 0, l);
          md5Transform(buffer);
          for(j = l; j + 63 < i; j += 64) {
              md5Memcpy(abyte1, abyte0, 0, j, 64);
              md5Transform(abyte1);
          }

          k = 0;
      }
      else {
          j = 0;
      }
      md5Memcpy(buffer, abyte0, k, j, i - j);
  }

  private void md5Final() {
      byte abyte0[] = new byte[8];
      Encode(abyte0, count, 8);
      int i = (int)(count[0] >>> 3) & 0x3f;
      int j = i >= 56 ? 120 - i : 56 - i;
      md5Update(PADDING, j);
      md5Update(abyte0, 8);
      Encode(digest, state, 16);
  }

  private void md5Memcpy(byte abyte0[], byte abyte1[], int i, int j, int k) {
      for(int l = 0; l < k; l++)
          abyte0[i + l] = abyte1[j + l];

  }

  private void md5Transform(byte abyte0[]) {
      long l = state[0];
      long l1 = state[1];
      long l2 = state[2];
      long l3 = state[3];
      long al[] = new long[16];
      Decode(al, abyte0, 64);
      l = FF(l, l1, l2, l3, al[0], 7L, 0xd76aa478L);
      l3 = FF(l3, l, l1, l2, al[1], 12L, 0xe8c7b756L);
      l2 = FF(l2, l3, l, l1, al[2], 17L, 0x242070dbL);
      l1 = FF(l1, l2, l3, l, al[3], 22L, 0xc1bdceeeL);
      l = FF(l, l1, l2, l3, al[4], 7L, 0xf57c0fafL);
      l3 = FF(l3, l, l1, l2, al[5], 12L, 0x4787c62aL);
      l2 = FF(l2, l3, l, l1, al[6], 17L, 0xa8304613L);
      l1 = FF(l1, l2, l3, l, al[7], 22L, 0xfd469501L);
      l = FF(l, l1, l2, l3, al[8], 7L, 0x698098d8L);
      l3 = FF(l3, l, l1, l2, al[9], 12L, 0x8b44f7afL);
      l2 = FF(l2, l3, l, l1, al[10], 17L, 0xffff5bb1L);
      l1 = FF(l1, l2, l3, l, al[11], 22L, 0x895cd7beL);
      l = FF(l, l1, l2, l3, al[12], 7L, 0x6b901122L);
      l3 = FF(l3, l, l1, l2, al[13], 12L, 0xfd987193L);
      l2 = FF(l2, l3, l, l1, al[14], 17L, 0xa679438eL);
      l1 = FF(l1, l2, l3, l, al[15], 22L, 0x49b40821L);
      l = GG(l, l1, l2, l3, al[1], 5L, 0xf61e2562L);
      l3 = GG(l3, l, l1, l2, al[6], 9L, 0xc040b340L);
      l2 = GG(l2, l3, l, l1, al[11], 14L, 0x265e5a51L);
      l1 = GG(l1, l2, l3, l, al[0], 20L, 0xe9b6c7aaL);
      l = GG(l, l1, l2, l3, al[5], 5L, 0xd62f105dL);
      l3 = GG(l3, l, l1, l2, al[10], 9L, 0x2441453L);
      l2 = GG(l2, l3, l, l1, al[15], 14L, 0xd8a1e681L);
      l1 = GG(l1, l2, l3, l, al[4], 20L, 0xe7d3fbc8L);
      l = GG(l, l1, l2, l3, al[9], 5L, 0x21e1cde6L);
      l3 = GG(l3, l, l1, l2, al[14], 9L, 0xc33707d6L);
      l2 = GG(l2, l3, l, l1, al[3], 14L, 0xf4d50d87L);
      l1 = GG(l1, l2, l3, l, al[8], 20L, 0x455a14edL);
      l = GG(l, l1, l2, l3, al[13], 5L, 0xa9e3e905L);
      l3 = GG(l3, l, l1, l2, al[2], 9L, 0xfcefa3f8L);
      l2 = GG(l2, l3, l, l1, al[7], 14L, 0x676f02d9L);
      l1 = GG(l1, l2, l3, l, al[12], 20L, 0x8d2a4c8aL);
      l = HH(l, l1, l2, l3, al[5], 4L, 0xfffa3942L);
      l3 = HH(l3, l, l1, l2, al[8], 11L, 0x8771f681L);
      l2 = HH(l2, l3, l, l1, al[11], 16L, 0x6d9d6122L);
      l1 = HH(l1, l2, l3, l, al[14], 23L, 0xfde5380cL);
      l = HH(l, l1, l2, l3, al[1], 4L, 0xa4beea44L);
      l3 = HH(l3, l, l1, l2, al[4], 11L, 0x4bdecfa9L);
      l2 = HH(l2, l3, l, l1, al[7], 16L, 0xf6bb4b60L);
      l1 = HH(l1, l2, l3, l, al[10], 23L, 0xbebfbc70L);
      l = HH(l, l1, l2, l3, al[13], 4L, 0x289b7ec6L);
      l3 = HH(l3, l, l1, l2, al[0], 11L, 0xeaa127faL);
      l2 = HH(l2, l3, l, l1, al[3], 16L, 0xd4ef3085L);
      l1 = HH(l1, l2, l3, l, al[6], 23L, 0x4881d05L);
      l = HH(l, l1, l2, l3, al[9], 4L, 0xd9d4d039L);
      l3 = HH(l3, l, l1, l2, al[12], 11L, 0xe6db99e5L);
      l2 = HH(l2, l3, l, l1, al[15], 16L, 0x1fa27cf8L);
      l1 = HH(l1, l2, l3, l, al[2], 23L, 0xc4ac5665L);
      l = II(l, l1, l2, l3, al[0], 6L, 0xf4292244L);
      l3 = II(l3, l, l1, l2, al[7], 10L, 0x432aff97L);
      l2 = II(l2, l3, l, l1, al[14], 15L, 0xab9423a7L);
      l1 = II(l1, l2, l3, l, al[5], 21L, 0xfc93a039L);
      l = II(l, l1, l2, l3, al[12], 6L, 0x655b59c3L);
      l3 = II(l3, l, l1, l2, al[3], 10L, 0x8f0ccc92L);
      l2 = II(l2, l3, l, l1, al[10], 15L, 0xffeff47dL);
      l1 = II(l1, l2, l3, l, al[1], 21L, 0x85845dd1L);
      l = II(l, l1, l2, l3, al[8], 6L, 0x6fa87e4fL);
      l3 = II(l3, l, l1, l2, al[15], 10L, 0xfe2ce6e0L);
      l2 = II(l2, l3, l, l1, al[6], 15L, 0xa3014314L);
      l1 = II(l1, l2, l3, l, al[13], 21L, 0x4e0811a1L);
      l = II(l, l1, l2, l3, al[4], 6L, 0xf7537e82L);
      l3 = II(l3, l, l1, l2, al[11], 10L, 0xbd3af235L);
      l2 = II(l2, l3, l, l1, al[2], 15L, 0x2ad7d2bbL);
      l1 = II(l1, l2, l3, l, al[9], 21L, 0xeb86d391L);
      state[0] += l;
      state[1] += l1;
      state[2] += l2;
      state[3] += l3;
  }

  private void Encode(byte abyte0[], long al[], int i) {
      int j = 0;
      for(int k = 0; k < i; k += 4) {
          abyte0[k] = (byte)(int)(al[j] & 255L);
          abyte0[k + 1] = (byte)(int)(al[j] >>> 8 & 255L);
          abyte0[k + 2] = (byte)(int)(al[j] >>> 16 & 255L);
          abyte0[k + 3] = (byte)(int)(al[j] >>> 24 & 255L);
          j++;
      }

  }

  private void Decode(long al[], byte abyte0[], int i) {
      int j = 0;
      for(int k = 0; k < i; k += 4) {
          al[j] = b2iu(abyte0[k]) | b2iu(abyte0[k + 1]) << 8 | b2iu(abyte0[k + 2]) << 16 | b2iu(abyte0[k + 3]) << 24;
          j++;
      }

  }

  public static long b2iu(byte byte0) {
      return byte0 >= 0 ? byte0 : byte0 & 0xff;
  }

  public static String byteHEX(byte byte0) {
      char ac[] = {
          '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
          'A', 'B', 'C', 'D', 'E', 'F'
      };
      char ac1[] = new char[2];
      ac1[0] = ac[byte0 >>> 4 & 0xf];
      ac1[1] = ac[byte0 & 0xf];
      String s = new String(ac1);
      return s;
  }

  /**
   * Tests a String to MD5.<br>
   * Usage: java net.lybbs.util.MD5<br>
   * or java net.lybbs.util.MD5 "some test String"
   * @param args input a test String, no input string for default value.
   */
  public static void main(String args[]) {
      MD5 md5 = MD5.getInstance();
	  String resultMd5=md5.getMD5("888888");
     System.out.println("jmhou=====>"+resultMd5);
  }
}