四舍五入四舍五入四舍五入四舍五入-蒲公英云

四舍五入四舍五入四舍五入四舍五入

叁歲伎倆 2023-10-09 14:37 103阅读 0赞

public class Test {
    public static void main(String[] args) {
        double num = 99.32511;
        BigDecimal bd = new BigDecimal(num);
        //保留两位数字，并且是截断不进行四舍五入
        String d1 = bd.setScale(2, RoundingMode.DOWN).toString();
        System.out.println(d1);
        //保留两位数字，四舍五入
        String d2 = bd.setScale(2, BigDecimal.ROUND_HALF_UP).toString();
        System.out.println(d2);
        // 测试加减乘除
        Test test = new Test();
        System.out.println(test.add(1.1, 2.2));
        System.out.println(test.subtract(3.3, 2.2));
        System.out.println(test.mul(3.3, 2.2));
        System.out.println(test.div(3.3, 2.2, 2));
    }
    // 加法运算
    private double add(double v1, double v2) {
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.add(b2).doubleValue();
    }
    // 减法运算
    private double subtract(double v1, double v2) {
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.subtract(b2).doubleValue();
    }
    // 乘法运算
    public double mul(double d1, double d2){
        BigDecimal b1 = new BigDecimal(Double.toString(d1));
        BigDecimal b2 = new BigDecimal(Double.toString(d2));
        return b1.multiply(b2).doubleValue();
    }
    // 除法运算
    public double div(double d1,double d2,int len) {
        BigDecimal b1 = new BigDecimal(Double.toString(d1));
        BigDecimal b2 = new BigDecimal(Double.toString(d2));
        return b1.divide(b2, len, BigDecimal.ROUND_HALF_UP).doubleValue();
    }
    /**
     * 比较大小
     * @param d1
     * @param d2
     * @return 1,0,-1
     */
    public static int compareTo(double d1, double d2) {
        BigDecimal b1 = new BigDecimal(Double.toString(d1));
        BigDecimal b2 = new BigDecimal(Double.toString(d2));
        return b1.compareTo(b2);
    }
}