code: 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;
  	}
docs: RS算法hash
  
  @param str 字符串
  @return hash值