四舍五入方法耗时排序

最新推荐文章于 2025-12-14 11:00:57 发布

原创最新推荐文章于 2025-12-14 11:00:57 发布 · 210 阅读

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public static void main(String[] args) {
    double d = (double) 250 / 365;

    long t33 = System.currentTimeMillis();
    String aa33= formatDouble3(d);
    System.out.println("值："+aa33+"；耗时:"+ (System.currentTimeMillis() - t33)+"ms ; :"+ d);
    System.out.println("==============四舍五入耗时排序===================");

    long t3 = System.currentTimeMillis();
    String aa3= formatDouble3(d);
    System.out.println("值："+aa3+"；耗时:"+ (System.currentTimeMillis() - t3)+"ms ; :"+ d);

    long t5 = System.currentTimeMillis();
    String aa5 = formatDouble1(d)+"";
    System.out.println("值："+aa5+"；耗时:"+ (System.currentTimeMillis() - t5)+"ms ; :"+ d);

    long t2 = System.currentTimeMillis();
    String aa2 = formatDouble4(d);
    System.out.println("值："+aa2+"；耗时:"+ (System.currentTimeMillis() - t2)+"ms ; :"+ d);

    long t4 = System.currentTimeMillis();
    String aa4 = formatDouble2(d)+"";
    System.out.println("值："+aa4+"；耗时:"+ (System.currentTimeMillis() - t4)+"ms ; :"+ d);

    long t1 = System.currentTimeMillis();
    String aa = formatDouble5(d);
    System.out.println("值："+aa+"；耗时:"+ (System.currentTimeMillis() - t1)+"ms ; :"+ d);


}

public static double formatDouble1(double d) {
    return (double)Math.round(d*10)/10;
}

public static double formatDouble2(double d) {
    // 新方法，如果不需要四舍五入，可以使用RoundingMode.DOWN
    BigDecimal bg = new BigDecimal(d).setScale(1, RoundingMode.UP);
    return bg.doubleValue();
}

public static String formatDouble3(double d) {
    NumberFormat nf = NumberFormat.getNumberInstance();

    // 保留两位小数
    nf.setMaximumFractionDigits(1);
    // 如果不需要四舍五入，可以使用RoundingMode.DOWN
    nf.setRoundingMode(RoundingMode.UP);
    return nf.format(d);
}

public static String formatDouble4(double d) {
    DecimalFormat df = new DecimalFormat("#.0");
    return df.format(d);
}

public static String formatDouble5(double d) {
    return String.format("%.1f", d);
}