public double normalise(String str) {
		double d = getProbability(str);
		d = d / str.length(); //词有长有短,乘以一个系数
		return d;
	}
public double normalise ( String str ) { double d = getProbability ( str ) ; d = d / str . length ( ) ; return d ; }
str的概率/length
@param str
@return