Java语言怎么将一组小数，按照小数点后的位数分门别类地存放到不同的字典里

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.ArrayList;

public class DecimalDictionary {
    public static void main(String[] args) {
        double[] decimals = {1.234, 2.34567, 3.12, 4.5678, 5.6789, 6.7, 7.8};

        Map<Integer, List<Double>> decimalDict = new HashMap<>();

        for (double num : decimals) {
            int precision = getPrecision(num);
            if (!decimalDict.containsKey(precision)) {
                decimalDict.put(precision, new ArrayList<Double>());
            }
            decimalDict.get(precision).add(num);
        }

        System.out.println(decimalDict);
    }

    public static int getPrecision(double num) {
        String decimalString = String.valueOf(num);
        int dotIndex = decimalString.indexOf(".");
        if (dotIndex == -1) {
            return 0; // 整数
        } else {
            return decimalString.length() - dotIndex - 1;
        }
    }
}