本文实例讲述了Java常用HASH算法。分享给大家供大家参考，具体如下：

/**

* Hash算法大全

* 推荐使用FNV1算法

* @algorithm None

* @author Goodzzp 2006-11-20

* @lastEdit Goodzzp 2006-11-20

* @editDetail Create

*/

public class HashAlgorithms

{

/**//**

* 加法hash

* @param key 字符串

* @param prime 一个质数

* @return hash结果

*/

public static int additiveHash(String key,int prime)

{

int hash,i;

for (hash = key.length(),i = 0; i < key.length(); i++)

hash += key.charAt(i);

return (hash % prime);

}

/**//**

* 旋转hash

* @param key 输入字符串

* @param prime 质数

* @return hash值

*/

public static int rotatingHash(String key,i;

for (hash=key.length(),i=0; i

hash = (hash<<4)^(hash>>28)^key.charAt(i);

return (hash % prime);

// return (hash ^ (hash>>10) ^ (hash>>20));

}

// 替代：

// 使用：hash = (hash ^ (hash>>10) ^ (hash>>20)) & mask;

// 替代：hash %= prime;

/**//**

* MASK值，随便找一个值，最好是质数

*/

static int M_MASK = 0x8765fed1;

/**//**

* 一次一个hash

* @param key 输入字符串

* @return 输出hash值

*/

public static int oneByOneHash(String key)

{

int hash,i;

for (hash=0,i=0; i

{

hash += key.charAt(i);

hash += (hash << 10);

hash ^= (hash >> 6);

}

hash += (hash << 3);

hash ^= (hash >> 11);

hash += (hash << 15);

// return (hash & M_MASK);

return hash;

}

/**//**

* Bernstein's hash

* @param key 输入字节数组

* @param level 初始hash常量

* @return 结果hash

*/

public static int bernstein(String key)

{

int hash = 0;

int i;

for (i=0; i

return hash;

}

//

/**/ Pearson's Hash

// char pearson(char[]key,ub4 len,char tab[256])

// {

// char hash;

// ub4 i;

// for (hash=len,i=0; i

// hash=tab[hash^key[i]];

// return (hash);

// }

/**/ CRC Hashing，计算crc,具体代码见其他

// ub4 crc(char *key,ub4 mask,ub4 tab[256])

// {

// ub4 hash,i;

// for (hash=len,i=0; i

// hash = (hash >> 8) ^ tab[(hash & 0xff) ^ key[i]];

// return (hash & mask);

// }

/**//**

* Universal Hashing

*/

public static int universal(char[]key,int mask,int[] tab)

{

int hash = key.length,i,len = key.length;

for (i=0; i

{

char k = key[i>>3];

if ((k&0x01) == 0) hash ^= tab[i+0];

if ((k&0x02) == 0) hash ^= tab[i+1];

if ((k&0x04) == 0) hash ^= tab[i+2];

if ((k&0x08) == 0) hash ^= tab[i+3];

if ((k&0x10) == 0) hash ^= tab[i+4];

if ((k&0x20) == 0) hash ^= tab[i+5];

if ((k&0x40) == 0) hash ^= tab[i+6];

if ((k&0x80) == 0) hash ^= tab[i+7];

}

return (hash & mask);

}

/**//**

* Zobrist Hashing

*/

public static int zobrist( char[] key,int[][] tab)

{

int hash,i;

for (hash=key.length,i=0; i

hash ^= tab[i][key[i]];

return (hash & mask);

}

// LOOKUP3

// 见Bob Jenkins(3).c文件

// 32位FNV算法

static int M_SHIFT = 0;

/**//**

* 32位的FNV算法

* @param data 数组

* @return int值

*/

public static int FNVHash(byte[] data)

{

int hash = (int)2166136261L;

for(byte b : data)

hash = (hash * 16777619) ^ b;

if (M_SHIFT == 0)

return hash;

return (hash ^ (hash >> M_SHIFT)) & M_MASK;

}

/**//**

* 改进的32位FNV算法1

* @param data 数组

* @return int值

*/

public static int FNVHash1(byte[] data)

{

final int p = 16777619;

int hash = (int)2166136261L;

for(byte b:data)

hash = (hash ^ b) * p;

hash += hash << 13;

hash ^= hash >> 7;

hash += hash << 3;

hash ^= hash >> 17;

hash += hash << 5;

return hash;

}

/**//**

* 改进的32位FNV算法1

* @param data 字符串

* @return int值

*/

public static int FNVHash1(String data)

{

final int p = 16777619;

int hash = (int)2166136261L;

for(int i=0;i

hash = (hash ^ data.charAt(i)) * p;

hash += hash << 13;

hash ^= hash >> 7;

hash += hash << 3;

hash ^= hash >> 17;

hash += hash << 5;

return hash;

}

/**//**

* Thomas Wang的算法，整数hash

*/

public static int intHash(int key)

{

key += ~(key << 15);

key ^= (key >>> 10);

key += (key << 3);

key ^= (key >>> 6);

key += ~(key << 11);

key ^= (key >>> 16);

return key;

}

/**//**

* RS算法hash

* @param str 字符串

*/

public static int RSHash(String str)

{

int b = 378551;

int a = 63689;

int hash = 0;

for(int i = 0; i < str.length(); i++)

{

hash = hash * a + str.charAt(i);

a = a * b;

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of RS Hash Function */

/**//**

* JS算法

*/

public static int JSHash(String str)

{

int hash = 1315423911;

for(int i = 0; i < str.length(); i++)

{

hash ^= ((hash << 5) + str.charAt(i) + (hash >> 2));

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of JS Hash Function */

/**//**

* PJW算法

*/

public static int PJWHash(String str)

{

int BitsInUnsignedInt = 32;

int ThreeQuarters = (BitsInUnsignedInt * 3) / 4;

int OneEighth = BitsInUnsignedInt / 8;

int HighBits = 0xFFFFFFFF << (BitsInUnsignedInt - OneEighth);

int hash = 0;

int test = 0;

for(int i = 0; i < str.length();i++)

{

hash = (hash << OneEighth) + str.charAt(i);

if((test = hash & HighBits) != 0)

{

hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));

}

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of P. J. Weinberger Hash Function */

/**//**

* ELF算法

*/

public static int ELFHash(String str)

{

int hash = 0;

int x = 0;

for(int i = 0; i < str.length(); i++)

{

hash = (hash << 4) + str.charAt(i);

if((x = (int)(hash & 0xF0000000L)) != 0)

{

hash ^= (x >> 24);

hash &= ~x;

}

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of ELF Hash Function */

/**//**

* BKDR算法

*/

public static int BKDRHash(String str)

{

int seed = 131; // 31 131 1313 13131 131313 etc..

int hash = 0;

for(int i = 0; i < str.length(); i++)

{

hash = (hash * seed) + str.charAt(i);

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of BKDR Hash Function */

/**//**

* SDBM算法

*/

public static int SDBMHash(String str)

{

int hash = 0;

for(int i = 0; i < str.length(); i++)

{

hash = str.charAt(i) + (hash << 6) + (hash << 16) - hash;

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of SDBM Hash Function */

/**//**

* DJB算法

*/

public static int DJBHash(String str)

{

int hash = 5381;

for(int i = 0; i < str.length(); i++)

{

hash = ((hash << 5) + hash) + str.charAt(i);

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of DJB Hash Function */

/**//**

* DEK算法

*/

public static int DEKHash(String str)

{

int hash = str.length();

for(int i = 0; i < str.length(); i++)

{

hash = ((hash << 5) ^ (hash >> 27)) ^ str.charAt(i);

}

return (hash & 0x7FFFFFFF);

}

/**//* End Of DEK Hash Function */

/**//**

* AP算法

*/

public static int APHash(String str)

{

int hash = 0;

for(int i = 0; i < str.length(); i++)

{

hash ^= ((i & 1) == 0) ? ( (hash << 7) ^ str.charAt(i) ^ (hash >> 3)) :

(~((hash << 11) ^ str.charAt(i) ^ (hash >> 5)));

}

// return (hash & 0x7FFFFFFF);

return hash;

}

/**//* End Of AP Hash Function */

/**//**

* JAVA自己带的算法

*/

public static int java(String str)

{

int h = 0;

int off = 0;

int len = str.length();

for (int i = 0; i < len; i++)

{

h = 31 * h + str.charAt(off++);

}

return h;

}

/**//**

* 混合hash算法，输出64位的值

*/

public static long mixHash(String str)

{

long hash = str.hashCode();

hash <<= 32;

hash |= FNVHash1(str);

return hash;

}

}

希望本文所述对大家java程序设计有所帮助。

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