hash algorithm modulo

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hash algorithm modulo

1. taken hashcode

 int hashcode = key.hashCode();这里的返回值可正可负
 只要key不变，hash值一定不变

2. ToTadashi

 由于取余后，只能是正整数，所以需要对hash值取正
 方式一：int absHash = Math.abs(hashcode);
 方式二：int result = hashcode&Integer.MAX_VALUE;
 经过方式二（效率高），任意数都会变为正

3. Remainder

 int num = result%3;
 得到一个0、1、2的任意数，此余数和redis的编号匹配