import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;

public class RateCalculate {

    public static void main(String[] args) {
        double divisorData = 73;
        double dividendData = 85;
        System.out.println(rateUtil(dividendData, divisorData,2));
        double rate = 76.356;
        System.out.println(rateUtil(rate,2));
    }

    /**
     * 求百分率
     * @param divisorData 除数
     * @param dividendData 被除数
     * @param num 小数位数
     * @return String
     */

    public static String rateUtil(Double divisorData,Double dividendData,Integer num){

        return getDecimalFormat(num).format(calculateRate(divisorData,dividendData))+ "%";
    }

    public static String rateUtil(Double rateData,Integer num){

        return getDecimalFormat(num).format(rateData)+ "%";
    }
    private static DecimalFormat getDecimalFormat(Integer num){
        DecimalFormat decimalFormat = (DecimalFormat) NumberFormat.getInstance();
        // 可以设置精确几位小数
        decimalFormat.setMaximumFractionDigits(num);
        // 模式 例如四舍五入
        decimalFormat.setRoundingMode(RoundingMode.HALF_UP);
        return decimalFormat;
    }
    public static double calculateRate(Double divisorData,Double dividendData){
        if (divisorData!=0&&divisorData!=null&&dividendData!=null){
            return dividendData/divisorData*100;
        }
        return 0;
    }

}

结果